TY  - THES
A1  - Patyniak, Magda
T1  - Seismotectonic segmentation, paleoearthquakes and style of deformation along the Northern Pamir thrust system, South Kyrgyzstan
T1  - Seismotektonische Segmentierung, Paläoerdbeben und Art der Deformation entlang des nördlichen Pamir-Überschiebungssystems, Südkirgisistan
N2  - The Pamir Frontal Thrust (PFT) located in the Trans Alai range in Central Asia is the principal active fault of the intracontinental India-Eurasia convergence zone and constitutes the northernmost boundary of the Pamir orogen at the NW edge of this collision zone. Frequent seismic activity and ongoing crustal shortening reflect the northward propagation of the Pamir into the intermontane Alai Valley. Quaternary deposits are being deformed and uplifted by the advancing thrust front of the Trans Alai range. The Alai Valley separates the Pamir range front from the Tien Shan mountains in the north; the Alai Valley is the vestige of a formerly contiguous basin that linked the Tadjik Depression in the west with the Tarim Basin in the east. GNSS measurements across the Central Pamir document a shortening rate of ~25 mm/yr, with a dramatic decrease of ~10-15 mm over a short distance across the northernmost Trans Alai range. This suggests that almost half of the shortening in the greater Pamir – Tien Shan collision zone is absorbed along the PFT. The short-term (geodetic) and long-term (geologic) shortening rates across the northern Pamir appear to be at odds with an apparent slip-rate discrepancy along the frontal fault system of the Pamir. Moreover, the present-day seismicity and historical records have not revealed great Mw > 7 earthquakes that might be expected with such a significant slip accommodation. In contrast, recent and historic earthquakes exhibit complex rupture patterns within and across seismotectonic segments bounding the Pamir mountain front, challenging our understanding of fault interaction and the seismogenic potential of this area, and leaving the relationships between seismicity and the geometry of the thrust front not well understood.
In this dissertation I employ different approaches to assess the seismogenic behavior along the PFT. Firstly, I provide paleoseismic data from five trenches across the central PFT segment (cPFT) and compute a segment-wide earthquake chronology over the past 16 kyr. This novel dataset provides important insights into the recurrence, magnitude, and rupture extent of past earthquakes along the cPFT. I interpret five, possibly six paleoearthquakes that have ruptured the Pamir mountain front since ∼7 ka and 16 ka, respectively. My results indicate that at least three major earthquakes ruptured the full-segment length and possibly crossed segment boundaries with a recurrence interval of ∼1.9 kyr and potential magnitudes of up to Mw 7.4. Importantly, I did not find evidence for great (i.e., Mw ≥8) earthquakes.
Secondly, I combine my paleoseimic results with morphometric analyses to establish a segment-wide distribution of the cumulative vertical separation along offset fluvial terraces and I model a long-term slip rate for the cPFT. My investigations reveal discrepancies between the extents of slip and rupture during apparent partial segment ruptures in the western half of the cPFT. Combined with significantly higher fault scarp offsets in this sector of the cPFT, the observations indicate a more mature fault section with a potential for future fault linkage. I estimate an average rate of horizontal motion for the cPFT of 4.1 ± 1.5 mm/yr during the past ∼5 kyr, which does not fully match the GNSS-derived present-day shortening rate of ∼10 mm/yr. This suggests a complex distribution of strain accumulation and potential slip partitioning between the cPFT and additional faults and folds within the Pamir that may be associated with a partially locked regional décollement.
The third part of the thesis provides new insights regarding the surface rupture of the 2008 Mw 6.6 Nura earthquake that ruptured along the eastern PFT sector. I explore this rupture in the context of its structural complexity by combining extensive field observations with high-resolution digital surface models. I provide a map of the rupture extent, net slip measurements, and updated regional geological observations. Based on this data I propose a tectonic model in this area associated with secondary flexural-slip faulting along steeply dipping bedding of folded Paleogene sedimentary strata that is related to deformation along a deeper blind thrust. Here, the strain release seems to be transferred from the PFT towards older inherited basement structures within the area of advanced Pamir-Tien Shan collision zone.
The extensive research of my dissertation results in a paleoseismic database of the past 16 ~kyr, which contributes to the understanding of the seismogenic behavior of the PFT, but also to that of segmented thrust-fault systems in active collisional settings. My observations underscore the importance of combining different methodological approaches in the geosciences, especially in structurally complex tectonic settings like the northern Pamir. Discrepancy between GNSS-derived present-day deformation rates and those from different geological archives in the central part, as well as the widespread distribution of the deformation due to earthquake triggered strain transfer in the eastern part reveals the complexity of this collision zone and calls for future studies involving multi-temporal and interdisciplinary approaches.
N2  - Die Pamir-Frontüberschiebung (PFT) des Trans-Alai-Gebirges in Zentralasien ist die wichtigste aktive Verwerfung der intrakontinentalen indisch-eurasischen Konvergenzzone und bildet die nördlichste Grenze des Pamir-Orogens am NW-Rand dieser Kollisionszone. Die intensive Seismizität und die fortschreitende Krustenverkürzung spiegeln die nach Norden gerichtete Verlagerung des Pamir in das intermontane Alai-Tal wider. Quartäre Ablagerungen werden durch die vorstoßende Überschiebungsfront des Trans-Alai-Gebirges sukzessive deformiert und angehoben. Das Alai-Tal trennt das Pamir-Gebirge vom Südrand des Tien Shan-Gebirges und verkörpert die Überreste eines ehemals zusammenhängenden Beckens, welches früher die Tadjik-Senke im Westen mit dem Tarim-Becken im Osten verband. GNSS-Messungen südlich der PFT im Bereich des Zentralpamirs dokumentieren eine Verkürzungsrate von 25 mm/Jahr, welche über
eine kurze Strecke zur nördlichen Front des Trans-Alai-Gebirges hin drastisch um 10-15 mm abnimmt. Dies lässt darauf schließen, dass fast die Hälfte der Einengung entlang der PFT absorbiert wird, welche sich in der Kollisionszone zwischen dem Pamir und dem Tien Shan befindet. Eine offensichtliche Abweichung zwischen den kurzfristigen (geodätischen) und langfristigen (geologischen) Verkürzungsraten im nördlichen Pamir weist auf eine Diskrepanz in den Versatzraten entlang des nördlichen frontalen Verwerfungssystems hin. Darüber hinaus weisen weder die heutige Seismizität noch die historischen Aufzeichnungen auf große Erdbeben der Stärke Mw > 7 hin, wie sie bei einer solch signifikanten Verschiebung zu erwarten wären. Stattdessen zeigen rezente und historische Erdbeben komplexe Bruchmuster innerhalb und quer zu seismotektonisch definierten Segmenten, die die Pamir-Gebirgsfront begrenzen,
was unser Verständnis der Verwerfungsinteraktion und des seismogenen Potenzials dieses Gebiets herausfordert. Die Wechselwirkungen zwischen Seismizität und der Geometrie der Überschiebungsfront sind somit nicht gut verstanden.
In dieser Dissertation verwende ich verschiedene Verfahren, um das seismogene Verhalten entlang der PFT zu bestimmen. Dazu werden zunächst paläoseismische Daten aus fünf Schürfgräben entlang des zentralen Segmentes der PFT (cPFT) erhoben und eine segmentweite Erdbebenchronologie zusammengestellt. Dieser neue Datensatz liefert wichtige Erkenntnisse über die Häufigkeit, die Stärke und das Bruchausmaß vergangener Erdbeben entlang der cPFT. Darauf basierend wurden fünf bzw. sechs Paläoerdbeben interpretiert, die sich entlang der nördlichen Pamir-Gebirgsfront in den letzten ∼7 ka bzw. ~16 ka ereigneten. Meine Ergebnisse deuten darauf hin, dass davon mindestens drei große Erdbeben die gesamte Länge des zentralen Segments durchbrochen haben und der Bruch möglicherweise sogar die Segmentgrenzen überschritten hat, mit einem Wiederholungsintervall von ∼1,9 kyr und potenziellen Magnituden von bis
zu Mw 7,4. Entscheidend an dieser Stelle ist, dass ich keine Hinweise auf sehr große (d.h. Mw ≥ 8) Erdbeben gefunden habe.
Meine paläoseismischen Ergebnisse werden anschließend mit morphometrischen Analysen entlang des zentralen PFT-Segmentes verknüpft, um eine segmentweite Verteilung der kumulativ versetzten Geländestufe entlang fluvialer Terrassen zu ermitteln. Aus dieser Verteilung wird eine langzeitliche Versatzrate für die cPFT modelliert. In der westlichen Hälfte der cPFT zeigen meine Untersuchungen deutliche Unstimmigkeiten zwischen dem Versatz und der Ausdehnung des Oberflächenbruchs auf. In Anbetracht der deutlich höheren Geländestufen im westlichen Bereich deuten die Beobachtungen auf einen reiferen Verwerfungsabschnitt hin. Somit besteht Potenzial für zukünftige Verbindung der Segmente und potenziell stärke Erdbeben.
Mit meinen Daten konnte ich eine mittlere horizontale Bewegungsrate von 4,1 ± 1,5 mm/Jahr während der letzten ∼5 kyr für die cPFT ermitteln, welche nicht vollständig mit der von GNSS abgeleiteten heutigen Verkürzungsrate von ∼10 mm/Jahr übereinstimmt. Dies deutet auf eine komplexe Verteilung des Spannungsaufbaus und eine potenzielle Aufteilung dieser Spannungen zwischen der cPFT und den übrigen Verwerfungen und Falten innerhalb des Pamirs hin, welche möglicherweise mit einem teilweise blockierten regionalen Décollement einhergehen.
Der letzte Teil der Arbeit liefert neue Erkenntnisse über den Oberflächenbruch des Nura-Erdbebens der Stärke 6,6 (Mw) aus dem Jahr 2008, das sich entlang der östlichen PFT ereignete. Ich untersuche diesen Bruch im Hinblick auf seine strukturelle Komplexität, indem ich umfangreiche Feldbeobachtungen mit hochauflösenden digitalen Oberflächenmodellen verknüpfe. Ich erstelle eine Karte der Bruchausdehnung, des gemessenen Gesamtversatzes und aktualisiere regionale geologische Beobachtungen. Auf der Grundlage dieser Daten entwickle ich für dieses Gebiet Szenarien für ein tektonisches Modell, das mit Biegegleitfalten in mesozoischen und känozoischen Sedimentschichten im Zusammenhang steht. Ich zeige, dass diese Formen mit älteren, kumulativ versetzten seismogenen Strukturen übereinzustimmen scheinen und auf eine wiederkehrende, langfristige Deformationsgeschichte entlang dieses Sektors der
nördlichen Pamir-Gebirgsfront hinweisen.
Die umfangreichen Forschungsarbeiten meiner Dissertation resultieren in einer paleoseismischen Datenbasis der letzten ~16,000 Jahre, welche zum Verständnis des seismogenen Verhaltens der PFT, aber auch zu dem von segmentierten Überschiebungssystemen in aktiven Kollisionsgebieten beitragen. Meine Beobachtungen unterstreichen, wie wichtig die Kombination verschiedener methodischer Ansätze in den Geowissenschaften ist, insbesondere in strukturell komplexen tektonischen Gebieten wie dem nördlichen Pamir. Die Diskrepanz zwischen den von GNSS abgeleiteten heutigen Deformationsraten und denen aus verschiedenen geologischen Archiven im zentralen Teil, und die weite Verbreitung der Deformation durch erdbebenbedingten Dehnungstransfer im östlichen Teil offenbart die Komplexität dieser Kollisionszone und erfordert künftige Studien mit multitemporalen und interdisziplinären Ansätzen.
KW  - paleoseismology
KW  - Paleoseismologie
KW  - Neotektonik
KW  - Strukturgeologie
KW  - quartäre Geochronologie
KW  - Zentral Asien
Y1  - 2022
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-577141
ER  - 
TY  - JOUR
A1  - Singh, Manudeo
A1  - Sinha, Rajiv
A1  - Mishra, Arjit
A1  - Babu, Suresh
T1  - Wetlandscape (dis)connectivity and fragmentation in a large wetland (Haiderpur) in west Ganga plains, India
JF  - Earth surface processes and landforms : the journal of the British Geomorphological Research Group
N2  - Wetlands are dynamic ecosystems that require continuous monitoring and assessment of degradation status to design strategies for their sustainable management. While hydrology provides the primary functional control for the wetland ecosystem, the loss of landscape connectivity influences wetland degradation in a major way as it leads to fragmentation. This article aims to integrate hydrogeomorphic and ecological concepts for the assessment of degradation status and its causal factors for a large wetland in the western Ganga plains, India, the Haiderpur, using a wetlandscape approach. We have used a remote-sensing-based approach, which offers a powerful tool for assessing and linking cross-scale structures, functions, and controls in a wetlandscape. The Haiderpur, a Ramsar site since December 2021, is an artificial wetland located on the right bank of the Ganga River wherein the inflows are controlled by a barrage constructed on the Ganga River apart from smaller tributaries flowing in from the north. A novel aspect of this work is the integration of river dynamics and its connectivity to the wetlandscape to understand the spatiotemporal variability in the waterspread area in the wetland. In this work, we have developed an integrated wetlandscape assessment approach by evaluating wetland's geomorphic and hydrological connectivity status for the period 1993-2019 (25 years) across three different spatial scales - regional, catchment, and wetland. We have highlighted the ecological implications of connectivity and patch dynamics for developing sustainable wetland management plans.
KW  - floodplain wetlands
KW  - Ganga River
KW  - geomorphic connectivity
KW  - wetland
KW  - degradation
KW  - wetland hydrology
Y1  - 2022
U6  - https://doi.org/10.1002/esp.5352
SN  - 0197-9337
SN  - 1096-9837
VL  - 47
IS  - 7
SP  - 1872
EP  - 1887
PB  - Wiley
CY  - New York, NY [u.a.]
ER  - 
TY  - BOOK
ED  - Falk, Gregor C.
ED  - Strecker, Manfred
ED  - Schneider, Simon
T1  - Alexander von Humboldt
BT  - multiperspective approaches
N2  - This book aims to view and to understand Alexander von Humboldt from different perspectives and in varying disciplinary contexts. His contributions addressed numerous topics in the earth but also life sciences—spanning from geo-botany, climatology, paleontology, oceanography, mineralogy, resources, and hydrogeology to links between the environmental impact of humans, erosion, and climate change. From the very beginning, he paved the way for a modern, integrated earth system science approach to decipher, characterize, and model the different forcing factors and their feedback mechanisms. It becomes obvious that Humboldt’s holistic approach is far beyond simple description and empiric data collection. As documented and analyzed in the different texts of this volume, he combines observation and analysis with emotions and subjective perceptions in a very affectionate way. However, this publication does not intend to add another encyclopedic text compilation but to observe and critically analyze this unique personality´s relevance in a modern context, particularly in discussing environmental and social key issues in the twenty-first century.
KW  - Alexander von Humboldt
KW  - multiperspective reception of AvH
KW  - biogeography
KW  - environmentalism
KW  - interdisciplinarity
KW  - earth system sciences
KW  - mining sciences
KW  - andean geology
KW  - intercultural understanding
KW  - expedition
KW  - Orinoco River system
KW  - historical geography
Y1  - 2022
SN  - 978-3-030-94007-2
SN  - 978-3-030-94008-9
SN  - 978-3-030-94010-2
U6  - https://doi.org/10.1007/978-3-030-94008-9
PB  - Springer
CY  - Cham
ER  - 
TY  - JOUR
A1  - Procyk, Roman
A1  - Lovejoy, Shaun
A1  - Hébert, Raphaёl
T1  - The fractional energy balance equation for climate projections through 2100
JF  - Earth system dynamics / European Geosciences Union
N2  - We produce climate projections through the 21st century using the fractional energy balance equation (FEBE): a generalization of the standard energy balance equation (EBE). The FEBE can be derived from Budyko-Sellers models or phenomenologically through the application of the scaling symmetry to energy storage processes, easily implemented by changing the integer order of the storage (derivative) term in the EBE to a fractional value. 
The FEBE is defined by three parameters: a fundamental shape parameter, a timescale and an amplitude, corresponding to, respectively, the scaling exponent h, the relaxation time tau and the equilibrium climate sensitivity (ECS). Two additional parameters were needed for the forcing: an aerosol recalibration factor alpha to account for the large aerosol uncertainty and a volcanic intermittency correction exponent upsilon. A Bayesian framework based on historical temperatures and natural and anthropogenic forcing series was used for parameter estimation. Significantly, the error model was not ad hoc but rather predicted by the model itself: the internal variability response to white noise internal forcing. 
The 90 % credible interval (CI) of the exponent and relaxation time were h = [0.33, 0.44] (median = 0.38) and tau = [2.4, 7.0] (median = 4.7) years compared to the usual EBE h = 1, and literature values of tau typically in the range 2-8 years. Aerosol forcings were too strong, requiring a decrease by an average factor alpha = [0.2, 1.0] (median = 0.6); the volcanic intermittency correction exponent was upsilon = [0.15, 0.41] (median = 0.28) compared to standard values alpha = upsilon = 1. The overpowered aerosols support a revision of the global modern (2005) aerosol forcing 90 % CI to a narrower range [ -1.0, -0.2] W m(-2). The key parameter ECS in comparison to IPCC AR5 (and to the CMIP6 MME), the 90 % CI range is reduced from [1.5, 4.5] K ([2.0, 5.5] K) to [1.6, 2.4] K ([1.5, 2.2] K), with median value lowered from 3.0 K (3.7 K) to 2.0 K (1.8 K) Similarly we found for the transient climate response (TCR), the 90 % CI range shrinks from [1.0, 2.5] K ([1.2, 2.8] K) to [1.2, 1.8] K ([1.1, 1.6] K) and the median estimate decreases from 1.8 K (2.0 K) to 1.5 K (1.4 K). As often seen in other observational-based studies, the FEBE values for climate sensitivities are therefore somewhat lower but still consistent with those in IPCC AR5 and the CMIP6 MME. <br /> Using these parameters, we made projections to 2100 using both the Representative Concentration Pathway (RCP) and Shared Socioeconomic Pathway (SSP) scenarios, and compared them to the corresponding CMIP5 and CMIP6 multi-model ensembles (MMEs). The FEBE historical reconstructions (1880-2020) closely follow observations, notably during the 1998-2014 slowdown ("hiatus"). We also reproduce the internal variability with the FEBE and statistically validate this against centennial-scale temperature observations. Overall, the FEBE projections were 10 %-15 % lower but due to their smaller uncertainties, their 90 % CIs lie completely within the GCM 90 % CIs. This agreement means that the FEBE validates the MME, and vice versa.
Y1  - 2022
U6  - https://doi.org/10.5194/esd-13-81-2022
SN  - 2190-4979
SN  - 2190-4987
VL  - 13
IS  - 1
SP  - 81
EP  - 107
PB  - Copernicus
CY  - Göttingen
ER  - 
TY  - JOUR
A1  - Rasigraf, Olivia
A1  - Wagner, Dirk
T1  - Landslides
BT  - an emerging model for ecosystem and soil chronosequence research
JF  - Earth science reviews : the international geological journal bridging the gap between research articles and textbooks
N2  - Erosion by landslides is a common phenomenon in mountain regions around the globe, affecting all climatic zones. Landslides facilitate bedrock weathering, pedogenesis and ecological succession, being key drivers of biodiversity. Landslide chronosequences have long been used for studies of vegetation succession in initial ecosystems, but they further offer ideal model systems for studies of soil development and microbial community succession. In this review we synthesize the state of knowledge on the role of landslides in ecosystems, their influence on element cycles and interactions with biota. Further, we discuss feedback mechanisms between global warming, landslide activity and greenhouse gas emissions. In the view of increasing anthropogenic influence and climate change, soils are becoming a critical resource. Due to their ubiquity, landslide chronosequences have the potential to provide critical insights into soil development under different climates and thereby contribute to future soil restoration efforts.
KW  - Landslides
KW  - Greenhouse gas emissions
KW  - Landslide chronosequences
KW  - Soil
KW  - microbial community
KW  - Erosion
KW  - Biodiversity
KW  - Microbial processes
KW  - Climate
KW  - change
Y1  - 2022
U6  - https://doi.org/10.1016/j.earscirev.2022.104064
SN  - 0012-8252
SN  - 1872-6828
VL  - 231
PB  - Elsevier
CY  - Amsterdam
ER  - 
TY  - JOUR
A1  - Bartholomäus, Alexander
A1  - Lipus, Daniel
A1  - Mitzscherling, Julia
A1  - MacLean, Joana
A1  - Wagner, Dirk
T1  - Draft Genome Sequence of Nocardioides alcanivorans NGK65(T), a Hexadecane-Degrading Bacterium
JF  - Microbiology Resource Announcements
N2  - The Gram-positive bacterium Nocardioides alcanivorans NGK65(T) was isolated from plastic-polluted soil and cultivated on medium with polyethylene as the single carbon source. Nanopore sequencing revealed the presence of candidate enzymes for the biodegradation of polyethylene. Here, we report the draft genome of this newly described member of the terrestrial plastisphere.
Y1  - 2022
U6  - https://doi.org/10.1128/mra.01213-21
SN  - 2576-098X
VL  - 11
IS  - 8
PB  - American Society for Microbiology
CY  - Washington
ER  - 
TY  - JOUR
A1  - Monhonval, Arthur
A1  - Strauss, Jens
A1  - Thomas, Maxime
A1  - Hirst, Catherine
A1  - Titeux, Hugues
A1  - Louis, Justin
A1  - Gilliot, Alexia
A1  - D'Aische, Eleonore du Bois
A1  - Pereira, Benoit
A1  - Vandeuren, Aubry
A1  - Grosse, Guido
A1  - Schirrmeister, Lutz
A1  - Jongejans, Loeka Laura
A1  - Ulrich, Mathias
A1  - Opfergelt, Sophie
T1  - Thermokarst processes increase the supply of stabilizing surfaces and elements (Fe, Mn, Al, and Ca) for mineral-organic carbon interactions
JF  - Permafrost and periglacial processes
N2  - The stabilizing properties of mineral-organic carbon (OC) interactions have been studied in many soil environments (temperate soils, podzol lateritic soils, and paddy soils). Recently, interest in their role in permafrost regions is increasing as permafrost was identified as a hotspot of change. In thawing ice-rich permafrost regions, such as the Yedoma domain, 327-466 Gt of frozen OC is buried in deep sediments. Interactions between minerals and OC are important because OC is located very near the mineral matrix. Mineral surfaces and elements could mitigate recent and future greenhouse gas emissions through physical and/or physicochemical protection of OC. The dynamic changes in redox and pH conditions associated with thermokarst lake formation and drainage trigger metal-oxide dissolution and precipitation, likely influencing OC stabilization and microbial mineralization. However, the influence of thermokarst processes on mineral-OC interactions remains poorly constrained. In this study, we aim to characterize Fe, Mn, Al, and Ca minerals and their potential protective role for OC. Total and selective extractions were used to assess the crystalline and amorphous oxides or complexed metal pools as well as the organic acids found within these pools. We analyzed four sediment cores from an ice-rich permafrost area in Central Yakutia, which were drilled (i) in undisturbed Yedoma uplands, (ii) beneath a recent lake formed within Yedoma deposits, (iii) in a drained thermokarst lake basin, and (iv) beneath a mature thermokarst lake from the early Holocene period. We find a decrease in the amount of reactive Fe, Mn, Al, and Ca in the deposits on lake formation (promoting reduction reactions), and this was largely balanced by an increase in the amount of reactive metals in the deposits on lake drainage (promoting oxidation reactions). We demonstrate an increase in the metal to C molar ratio on thermokarst process, which may indicate an increase in metal-C bindings and could provide a higher protective role against microbial mineralization of organic matter. Finally, we find that an increase in mineral-OC interactions corresponded to a decrease in CO2 and CH4 gas emissions on thermokarst process. Mineral-OC interactions could mitigate greenhouse gas production from permafrost thaw as soon as lake drainage occurs.
KW  - Arctic
KW  - organic carbon stabilization
KW  - permafrost
KW  - redox processes
KW  - thaw
KW  - Yedoma
Y1  - 2022
U6  - https://doi.org/10.1002/ppp.2162
SN  - 1045-6740
SN  - 1099-1530
VL  - 33
IS  - 4
SP  - 452
EP  - 469
PB  - Wiley
CY  - Hoboken
ER  - 
TY  - JOUR
A1  - Nomosatryo, Sulung
A1  - Tjallingii, Rik
A1  - Henny, Cynthia
A1  - Ridwansyah, Iwan
A1  - Wagner, Dirk
A1  - Tomás, Sara
A1  - Kallmeyer, Jens
T1  - Surface sediment composition and depositional environments in tropical Lake Sentani, Papua Province, Indonesia
JF  - Journal of Paleolimnology
N2  - Tropical Lake Sentani in the Indonesian Province Papua consists of four separate basins and is surrounded by a catchment with a very diverse geology. We characterized the surface sediment (upper 5 cm) of the lake's four sub-basins based on multivariate statistical analyses (principal component analysis, hierarchical clustering) of major element compositions obtained by X-ray fluorescence scanning. Three types of sediment are identified based on distinct compositional differences between rivers, shallow/proximal and deep/distal lake sediments. The different sediment types are mainly characterized by the correlation of elements associated with redox processes (S, Mn, Fe), carbonates (Ca), and detrital input (Ti, Al, Si, K) derived by river discharge. The relatively coarse-grained river sediments mainly derive form the mafic catchment geology and contribution of the limestone catchment geology is only limited. Correlation of redox sensitive and detrital elements are used to reveal oxidation conditions, and indicate oxic conditions in river samples and reducing conditions for lake sediments. Organic carbon (TOC) generally correlates with redox sensitive elements, although a correlation between TOC and individual elements change strongly between the three sediment types. Pyrite is the quantitatively dominant reduced sulfur mineral, monosulfides only reach appreciable concentrations in samples from rivers draining mafic and ultramafic catchments. Our study shows large spatial heterogeneity within the lake's sub-basins that is mainly caused by catchment geology and topography, river runoff as well as the bathymetry and the depth of the oxycline. We show that knowledge about lateral heterogeneity is crucial for understanding the geochemical and sedimentological variations recorded by these sediments. The highly variable conditions make Lake Sentani a natural laboratory, with its different sub-basins representing different depositional environments under identical tropical climate conditions.
KW  - Tropical lake
KW  - Lacustrine sediment
KW  - XRF analysis
KW  - Multivariate
KW  - statistics
Y1  - 2022
U6  - https://doi.org/10.1007/s10933-022-00259-4
SN  - 0921-2728
SN  - 1573-0417
PB  - Springer
CY  - Dordrecht
ER  - 
TY  - JOUR
A1  - Bufe, Aaron
A1  - Cook, Kristen L.
A1  - Galy, Albert
A1  - Wittmann, Hella
A1  - Hovius, Niels
T1  - The effect of lithology on the relationship between denudation rate and chemical weathering pathways
BT  - evidence from the eastern Tibetan Plateau
JF  - Earth surface dynamics
N2  - The denudation of rocks in mountain belts exposes a range of fresh minerals to the surface of the Earth that are chemically weathered by acidic and oxygenated fluids. The impact of the resulting coupling between denudation and weathering rates fundamentally depends on the types of minerals that are weathering. Whereas silicate weathering sequesters CO2, the combination of sulfide oxidation and carbonate dissolution emits CO2 to the atmosphere. Here, we combine the concentrations of dissolved major elements in stream waters with Be-10 basin-wide denudation rates from 35 small catchments in eastern Tibet to elucidate the importance of lithology in modulating the relationships between denudation rate, chemical weathering pathways, and CO2 consumption or release. Our catchments span 3 orders of magnitude in denudation rate in low-grade flysch, high-grade metapelites, and granitoid rocks. For each stream, we estimate the concentrations of solutes sourced from silicate weathering, carbonate dissolution, and sulfide oxidation using a mixing model. We find that for all lithologies, cation concentrations from silicate weathering are largely independent of denudation rate, but solute concentrations from carbonates and, where present, sulfides increase with increasing denudation rate. With increasing denudation rates, weathering may therefore shift from consuming to releasing CO2 in both (meta)sedimentary and granitoid lithologies. For a given denudation rate, we report dissolved solid concentrations and inferred weathering fluxes in catchments underlain by (meta)sedimentary rock that are 2-10 times higher compared to catchments containing granitoid lithologies, even though climatic and topographic parameters do not vary systematically between these catchments. Thus, varying proportions of exposed (meta)sedimentary and igneous rocks during orogenesis could lead to changes in the sequestration and release of CO2 that are independent of denudation rate.
Y1  - 2022
U6  - https://doi.org/10.5194/esurf-10-513-2022
SN  - 2196-6311
SN  - 2196-632X
VL  - 10
IS  - 3
SP  - 513
EP  - 530
PB  - Copernicus
CY  - Göttingen
ER  - 
TY  - JOUR
A1  - Buter, Anuschka
A1  - Heckmann, Tobias
A1  - Filisetti, Lorenzo
A1  - Savi, Sara
A1  - Mao, Luca
A1  - Gems, Bernhard
A1  - Comiti, Francesco
T1  - Effects of catchment characteristics and hydro-meteorological scenarios on sediment connectivity in glacierised catchments
JF  - Geomorphology : an international journal on pure and applied geomorphology
N2  - In the past decade, sediment connectivity has become a widely recognized characteristic of a geomorphic system. However, the quantification of functional connectivity (i.e. connectivity which arises due to the actual occurrence of sediment transport processes) and its variation over space and time is still a challenge. In this context, this study assesses the effects of expected future phenomena in the context of climate change (i.e. glacier retreat, permafrost degradation or meteorological extreme events) on sediment transport dynamics in a glacierised Alpine basin. The study area is the Sulden river basin (drainage area 130 km(2)) in the Italian Alps, which is composed of two geomorphologically diverse sub-basins. Based on graph theory, we evaluated the spatio-temporal variations in functional connectivity in these two sub-basins. The graph-object, obtained by manually mapping sediment transport processes between landforms, was adapted to 6 different hydro-meteorological scenarios, which derive from combining base, heatwave and rainstorm conditions with snowmelt and glacier-melt periods. For each scenario and each sub-basin, the sediment transport network and related catchment characteristics were analysed. To compare the effects of the scenarios on functional connectivity, we introduced a connectivity degree, calculated based on the area of the landforms involved in sediment cascades. Results indicate that the area of the basin connected to its outlet in terms of sediment transport might feature a six-fold increase in case of rainstorm conditions compared to "average " meteorological conditions assumed for the base scenario. Furthermore, markedly different effects of climate change on sediment connectivity are expected between the two sub-catchments due to their contrasting morphological and lithological characteristics, in terms of relative importance of rainfall triggered colluvial processes vs temperature-driven proglacial fluvial dynamics.
KW  - Functional connectivity
KW  - Graph theory
KW  - Climate change
KW  - Geomorphic systems
Y1  - 2022
U6  - https://doi.org/10.1016/j.geomorph.2022.108128
SN  - 0169-555X
SN  - 1872-695X
VL  - 402
PB  - Elsevier
CY  - Amsterdam
ER  - 
TY  - JOUR
A1  - Foong, Adrian
A1  - Pradhan, Prajal
A1  - Frör, Oliver
A1  - Kropp, Jürgen P.
T1  - Adjusting agricultural emissions for trade matters for climate change mitigation
JF  - Nature Communications
N2  - Reducing greenhouse gas emissions in food systems is becoming more challenging as food is increasingly consumed away from producer regions, highlighting the need to consider emissions embodied in trade in agricultural emissions accounting. 
To address this, our study explores recent trends in trade-adjusted agricultural emissions of food items at the global, regional, and national levels. 

We find that emissions are largely dependent on a country’s consumption patterns and their agricultural emission intensities relative to their trading partners’. 
The absolute differences between the production-based and trade-adjusted emissions accounting approaches are especially apparent for major agricultural exporters and importers and where large shares of emission-intensive items such as ruminant meat, milk products and rice are involved. 

In relative terms, some low-income and emerging and developing economies with consumption of high emission intensity food products show large differences between approaches. 
Similar trends are also found under various specifications that account for trade and re-exports differently. 
These findings could serve as an important element towards constructing national emissions reduction targets that consider trading partners, leading to more effective emissions reductions overall.
Y1  - 2022
U6  - https://doi.org/10.1038/s41467-022-30607-x
SN  - 2041-1723
VL  - 13
IS  - 1
PB  - Nature Publishing Group
CY  - London
ER  - 
TY  - JOUR
A1  - Daskalopoulou, Kyriaki
A1  - D'Alessandro, Walter
A1  - Longo, Manfredi
A1  - Pecoraino, Giovannella
A1  - Calabrese, Sergio
T1  - Shallow sea gas manifestations in the Aegean Sea (Greece) as natural analogs to study ocean acidification
BT  - first catalog and geochemical characterization
JF  - Frontiers in Marine Science
N2  - The concepts of CO2 emission, global warming, climate change, and their environmental impacts are of utmost importance for the understanding and protection of the ecosystems. 
Among the natural sources of gases into the atmosphere, the contribution of geogenic sources plays a crucial role. However, while subaerial emissions are widely studied, submarine outgassing is not yet well understood. 

In this study, we review and catalog 122 literature and unpublished data of submarine emissions distributed in ten coastal areas of the Aegean Sea. This catalog includes descriptions of the degassing vents through in situ observations, their chemical and isotopic compositions, and flux estimations. 
Temperatures and pH data of surface seawaters in four areas affected by submarine degassing are also presented. 

This overview provides useful information to researchers studying the impact of enhanced seawater CO2 concentrations related either to increasing CO2 levels in the atmosphere or leaking carbon capture and storage systems.
KW  - CO2 emissions
KW  - submarine gas vents
KW  - geogenic degassing
KW  - environmental
KW  - impact
KW  - Greek Islands
KW  - gas flux
Y1  - 2022
U6  - https://doi.org/10.3389/fmars.2021.775247
SN  - 2296-7745
VL  - 8
PB  - Frontiers Media
CY  - Lausanne
ER  - 
TY  - JOUR
A1  - Müller, Daniela
A1  - Neugebauer, Ina
A1  - Ben Dor, Yoav
A1  - Enzel, Yehouda
A1  - Schwab, Markus Julius
A1  - Tjallingii, Rik
A1  - Brauer, Achim
T1  - Phases of stability during major hydroclimate change ending the Last Glacial in the Levant
JF  - Scientific reports
N2  - In-depth understanding of the reorganization of the hydrological cycle in response to global climate change is crucial in highly sensitive regions like the eastern Mediterranean, where water availability is a major factor for socioeconomic and political development. 
The sediments of Lake Lisan provide a unique record of hydroclimatic change during the last glacial to Holocene transition (ca. 24-11 ka) with its tremendous water level drop of similar to 240 m that finally led to its transition into the present hypersaline water body-the Dead Sea. 
Here we utilize high-resolution sedimentological analyses from the marginal terraces and deep lake to reconstruct an unprecedented seasonal record of the last millennia of Lake Lisan. Aragonite varve formation in intercalated intervals of our record demonstrates that a stepwise long-term lake level decline was interrupted by almost one millennium of rising or stable water level. 
Even periods of pronounced water level drops indicated by gypsum deposition were interrupted by decades of positive water budgets. 
Our results thus highlight that even during major climate change at the end of the last glacial, decadal to millennial periods of relatively stable or positive moisture supply occurred which could have been an important premise for human sedentism.
Y1  - 2022
U6  - https://doi.org/10.1038/s41598-022-10217-9
SN  - 2045-2322
VL  - 12
IS  - 1
PB  - Macmillan Publishers Limited, part of Springer Nature
CY  - London
ER  - 
TY  - JOUR
A1  - Ortiz, Gustavo
A1  - Saez, Mauro
A1  - Alvarado, Patricia
A1  - Rivas, Carolina
A1  - García, Víctor Hugo
A1  - Alonso, Ricardo
A1  - Zullo, Fernando Morales
T1  - Seismotectonic characterization of the 1948 (M-W 6.9) Anta earthquake Santa  Barbara System, central Andes broken foreland of northwestern Argentina
JF  - Journal of South American earth sciences
N2  - The region of the Andean back-arc of northwestern Argentina has been struck by several magnitude >= 6 crustal earthquakes since the first historically recorded event in 1692. One of these events corresponds to the Anta earthquake on 25 August 1948, with epicenter in the Santa Barbara System causing three deaths and severe damage in Salta and Jujuy provinces with maximum Modified Mercalli seismic intensities (MMI) of IX. We collected and digitized analog seismograms of this earthquake from worldwide seismic observatories in order to perform first-motion analysis and modeling of long-period teleseismic P-waveforms. Our results indicate a simple seismic source of M0 = 2.85 x 1019 N m consistent with a moment magnitude Mw = 6.9. We have also tested for the focal depth determining a shallow source at 8 km with a reverse focal mechanism solution with a minor dextral strike-slip component (strike 20 degrees, dip 30 degrees, rake 120 degrees) from the best fit of waveforms. Using magnitude size empirical relationships, the comparison of the obtained Mw 6.9 magnitude value and the ca. 10,000 km2 area of MMI >= IX from our seismic intensity map, which was obtained from newspaper and many historical reports, indicates a rupture length of 42 +/- 8 km for the Anta earthquake. We show our results in a 3D geological model around the epicentral area, which integrates modern seismicity, geological data, and information of a previously studied east-west cross section located a few kilometers south of the 1948 epicenter. The integration of all available information provides evidence of the re-activation of the Pie de la Sierra del Gallo fault during the 1948 Mw 6.9 shallow earthquake; this thrust fault bounds the Santa Barbara System along its western foothill.
KW  - Active tectonics
KW  - Analog historical seismograms
KW  - Andean back-arc;
KW  - Thick-skinned tectonics
KW  - Central Andes
Y1  - 2022
U6  - https://doi.org/10.1016/j.jsames.2022.103822
SN  - 0895-9811
SN  - 1873-0647
VL  - 116
PB  - Elsevier
CY  - Oxford
ER  - 
TY  - JOUR
A1  - Krämer, Hauke Kai
A1  - Gelbrecht, Maximilian
A1  - Pavithran, Induja
A1  - Sujith, Ravindran
A1  - Marwan, Norbert
T1  - Optimal state space reconstruction via Monte Carlo decision tree search
JF  - Nonlinear Dynamics
N2  - A novel idea for an optimal time delay state space reconstruction from uni- and multivariate time series is presented. The entire embedding process is considered as a game, in which each move corresponds to an embedding cycle and is subject to an evaluation through an objective function. This way the embedding procedure can be modeled as a tree, in which each leaf holds a specific value of the objective function. By using a Monte Carlo ansatz, the proposed algorithm populates the tree with many leafs by computing different possible embedding paths and the final embedding is chosen as that particular path, which ends at the leaf with the lowest achieved value of the objective function. The method aims to prevent getting stuck in a local minimum of the objective function and can be used in a modular way, enabling practitioners to choose a statistic for possible delays in each embedding cycle as well as a suitable objective function themselves. The proposed method guarantees the optimization of the chosen objective function over the parameter space of the delay embedding as long as the tree is sampled sufficiently. As a proof of concept, we demonstrate the superiority of the proposed method over the classical time delay embedding methods using a variety of application examples. We compare recurrence plot-based statistics inferred from reconstructions of a Lorenz-96 system and highlight an improved forecast accuracy for map-like model data as well as for palaeoclimate isotope time series. Finally, we utilize state space reconstruction for the detection of causality and its strength between observables of a gas turbine type thermoacoustic combustor.
KW  - State space reconstruction
KW  - Embedding
KW  - Optimization
KW  - Time series analysis
KW  - Causality
KW  - Prediction
KW  - Recurrence analysis
Y1  - 2022
U6  - https://doi.org/10.1007/s11071-022-07280-2
SN  - 0924-090X
SN  - 1573-269X
VL  - 108
IS  - 2
SP  - 1525
EP  - 1545
PB  - Springer
CY  - Dordrecht
ER  - 
TY  - JOUR
A1  - Svennevig, Kristian
A1  - Hermanns, Reginald L.
A1  - Keiding, Marie
A1  - Binder, Daniel
A1  - Citterio, Michele
A1  - Dahl-Jensen, Trine
A1  - Mertl, Stefan
A1  - Sørensen, Erik Vest
A1  - Voss, Peter Henrik
T1  - A large frozen debris avalanche entraining warming permafrost ground-the June 2021 Assapaat landslibe, West Greenland
JF  - Landslides
N2  - A large landslide (frozen debris avalanche) occurred at Assapaat on the south coast of the Nuussuaq Peninsula in Central West Greenland on June 13, 2021, at 04:04 local time. We present a compilation of available data from field observations, photos, remote sensing, and seismic monitoring to describe the event. Analysis of these data in combination with an analysis of pre- and post-failure digital elevation models results in the first description of this type of landslide. The frozen debris avalanche initiated as a 6.9 * 10(6) m(3) failure of permafrozen talus slope and underlying colluvium and till at 600-880 m elevation. It entrained a large volume of permafrozen colluvium along its 2.4 km path in two subsequent entrainment phases accumulating a total volume between 18.3 * 10(6) and 25.9 * 10(6) m(3). About 3.9 * 10(6) m(3) is estimated to have entered the Vaigat strait; however, no tsunami was reported, or is evident in the field. This is probably because the second stage of entrainment along with a flattening of slope angle reduced the mobility of the frozen debris avalanche. We hypothesise that the initial talus slope failure is dynamically conditioned by warming of the ice matrix that binds the permafrozen talus slope. When the slope ice temperature rises to a critical level, its shear resistance is reduced, resulting in an unstable talus slope prone to failure. Likewise, we attribute the large-scale entrainment to increasing slope temperature and take the frozen debris avalanche as a strong sign that the permafrost in this region is increasingly at a critical state. Global warming is enhanced in the Arctic and frequent landslide events in the past decade in Western Greenland let us hypothesise that continued warming will lead to an increase in the frequency and magnitude of these types of landslides. Essential data for critical arctic slopes such as precipitation, snowmelt, and ground and surface temperature are still missing to further test this hypothesis. It is thus strongly required that research funds are made available to better predict the change of landslide threat in the Arctic.
KW  - Assapaat landslide
KW  - Slope temperature
KW  - Global warming
Y1  - 2022
U6  - https://doi.org/10.1007/s10346-022-01922-7
SN  - 1612-510X
SN  - 1612-5118
VL  - 19
SP  - 2549
EP  - 2567
PB  - Springer
CY  - Heidelberg
ER  - 
TY  - JOUR
A1  - Stevanato, Luca
A1  - Baroni, Gabriele
A1  - Oswald, Sascha
A1  - Lunardon, Marcello
A1  - Mareš, Vratislav
A1  - Marinello, Francesco
A1  - Moretto, Sandra
A1  - Polo, Matteo
A1  - Sartori, Paolo
A1  - Schattan, Paul
A1  - Rühm, Werner
T1  - An alternative incoming correction for cosmic-ray neutron sensing observations using local muon measurement
JF  - Geophysical research letters
N2  - Measuring the variability of incoming neutrons locally would be usefull for the cosmic-ray neutron sensing (CRNS) method. As the measurement of high energy neutrons is not so easy, alternative particles can be considered for such purpose. Among them, muons are particles created from the same cascade of primary cosmic-ray fluxes that generate neutrons at the ground. In addition, they can be easily detected by small and relatively inexpensive detectors. For these reasons they could provide a suitable local alternative to incoming corrections based on remote neutron monitor data. The reported measurements demonstrated that muon detection system can detect incoming cosmic-ray variations locally. Furthermore the precision of this measurement technique is considered adequate for many CRNS applications.
KW  - CRNS
KW  - soil-moisture
KW  - neutrons
KW  - muons
KW  - cosmic-rays
Y1  - 2022
U6  - https://doi.org/10.1029/2021GL095383
SN  - 0094-8276
SN  - 1944-8007
VL  - 49
IS  - 6
PB  - American Geophysical Union
CY  - Washington
ER  - 
TY  - JOUR
A1  - Jozi Najafabadi, Azam
A1  - Haberland, Christian
A1  - Le Breton, Eline
A1  - Handy, Mark R.
A1  - Verwater, Vincent F.
A1  - Heit, Benjamin
A1  - Weber, Michael
T1  - Constraints on crustal structure in the vicinity of the adriatic indenter (European Alps) from Vp and Vp/Vs local earthquake tomography
JF  - Journal of geophysical research : Solid earth
N2  - In this study, 3-D models of P-wave velocity (Vp) and P-wave and S-wave ratio (Vp/Vs) of the crust and upper mantle in the Eastern and eastern Southern Alps (northern Italy and southern Austria) were calculated using local earthquake tomography (LET). The data set includes high-quality arrival times from well-constrained hypocenters observed by the dense, temporary seismic networks of the AlpArray AASN and SWATH-D. The resolution of the LET was checked by synthetic tests and analysis of the model resolution matrix. The small inter-station spacing (average of similar to 15 km within the SWATH-D network) allowed us to image crustal structure at unprecedented resolution across a key part of the Alps. The derived P velocity model revealed a highly heterogeneous crustal structure in the target area. One of the main findings is that the lower crust is thickened, forming a bulge at 30-50 km depth just south of and beneath the Periadriatic Fault and the Tauern Window. This indicates that the lower crust decoupled both from its mantle substratum as well as from its upper crust. The Moho, taken to be the iso-velocity contour of Vp = 7.25 km/s, agrees with the Moho depth from previous studies in the European and Adriatic forelands. It is shallower on the Adriatic side than on the European side. This is interpreted to indicate that the European Plate is subducted beneath the Adriatic Plate in the Eastern and eastern Southern Alps.
KW  - European Alps
KW  - crustal structure
KW  - subduction
KW  - seismic tomography
KW  - body waves
Y1  - 2022
U6  - https://doi.org/10.1029/2021JB023160
SN  - 2169-9313
SN  - 2169-9356
VL  - 127
IS  - 2
PB  - American Geophysical Union
CY  - Washington
ER  - 
TY  - JOUR
A1  - Ramachandran, Srikanthan
A1  - Rupakheti, Maheswar
A1  - Cherian, R.
A1  - Lawrence, Mark
T1  - Climate Benefits of Cleaner Energy Transitions in East and South Asia Through Black Carbon Reduction
JF  - Frontiers in environmental science
N2  - The state of air pollution has historically been tightly linked to how we produce and use energy. Air pollutant emissions over Asia are now changing rapidly due to cleaner energy transitions; however, magnitudes of benefits for climate and air quality remain poorly quantified. The associated risks involve adverse health impacts, reduced agricultural yields, reduced freshwater availability, contributions to climate change, and economic costs. We focus particularly on climate benefits of energy transitions by making first-time use of two decades of high quality observations of atmospheric loading of light-absorbing black carbon (BC) over Kanpur (South Asia) and Beijing (East Asia) and relating these observations to changing energy, emissions, and economic trends in India and China. Our analysis reveals that absorption aerosol optical depth (AAOD) due to BC has decreased substantially, by 40% over Kanpur and 60% over Beijing between 2001 and 2017, and thus became decoupled from regional economic growth. Furthermore, the resultant decrease in BC emissions and BC AAOD over Asia is regionally coherent and occurs primarily due to transitions into cleaner energies (both renewables and fossil fuels) and not due to the decrease in primary energy supply or decrease in use of fossil use and biofuels and waste. Model simulations show that BC aerosols alone contribute about half of the surface temperature change (warming) of the total forcing due to greenhouse gases, natural and internal variability, and aerosols, thus clearly revealing the climate benefits due to a reduction in BC emissions, which would significantly reduce global warming. However, this modeling study excludes responses from natural variability, circulation, and sea ice responses, which cause relatively strong temperature fluctuations that may mask signals from BC aerosols. Our findings show additional benefits for climate (beyond benefits of CO2 reduction) and for several other issues of sustainability over South and East Asia, provide motivation for ongoing cleaner energy production, and consumption transitions, especially when they are associated with reduced emissions of air pollutants. Such an analysis connecting the trends in energy transitions and aerosol absorption loading, unavailable so far, is crucial for simulating the aerosol climate impacts over Asia which is quite uncertain.
KW  - cleaner energy transitions
KW  - Asia
KW  - air pollution
KW  - black carbon
KW  - climate benefits
Y1  - 2022
U6  - https://doi.org/10.3389/fenvs.2022.842319
SN  - 2296-665X
VL  - 10
PB  - Frontiers Media
CY  - Lausanne
ER  - 
TY  - JOUR
A1  - Fernandez-Palomino, Carlos Antonio
A1  - Hattermann, Fred
A1  - Krysanova, Valentina
A1  - Lobanova, Anastasia
A1  - Vega-Jacome, Fiorella
A1  - Lavado, Waldo
A1  - Santini, William
A1  - Aybar, Cesar
A1  - Bronstert, Axel
T1  - A novel high-resolution gridded precipitation dataset for peruvian and ecuadorian watersheds
BT  - development and hydrological evaluation
JF  - Journal of hydrometeorology
N2  - A novel approach for estimating precipitation patterns is developed here and applied to generate a new hydrologically corrected daily precipitation dataset, called RAIN4PE (Rain for Peru and Ecuador), at 0.1 degrees spatial resolution for the period 1981-2015 covering Peru and Ecuador. It is based on the application of 1) the random forest method to merge multisource precipitation estimates (gauge, satellite, and reanalysis) with terrain elevation, and 2) observed and modeled streamflow data to first detect biases and second further adjust gridded precipitation by inversely applying the simulated results of the ecohydrological model SWAT (Soil and Water Assessment Tool). Hydrological results using RAIN4PE as input for the Peruvian and Ecuadorian catchments were compared against the ones when feeding other uncorrected (CHIRP and ERA5) and gauge-corrected (CHIRPS, MSWEP, and PISCO) precipitation datasets into the model. For that, SWAT was calibrated and validated at 72 river sections for each dataset using a range of performance metrics, including hydrograph goodness of fit and flow duration curve signatures. Results showed that gauge-corrected precipitation datasets outperformed uncorrected ones for streamflow simulation. However, CHIRPS, MSWEP, and PISCO showed limitations for streamflow simulation in several catchments draining into the Pacific Ocean and the Amazon River. RAIN4PE provided the best overall performance for streamflow simulation, including flow variability (low, high, and peak flows) and water budget closure. The overall good performance of RAIN4PE as input for hydrological modeling provides a valuable criterion of its applicability for robust countrywide hydrometeorological applications, including hydroclimatic extremes such as droughts and floods. Significance StatementWe developed a novel precipitation dataset RAIN4PE for Peru and Ecuador by merging multisource precipitation data (satellite, reanalysis, and ground-based precipitation) with terrain elevation using the random forest method. Furthermore, RAIN4PE was hydrologically corrected using streamflow data in watersheds with precipitation underestimation through reverse hydrology. The results of a comprehensive hydrological evaluation showed that RAIN4PE outperformed state-of-the-art precipitation datasets such as CHIRP, ERA5, CHIRPS, MSWEP, and PISCO in terms of daily and monthly streamflow simulations, including extremely low and high flows in almost all Peruvian and Ecuadorian catchments. This underlines the suitability of RAIN4PE for hydrometeorological applications in this region. Furthermore, our approach for the generation of RAIN4PE can be used in other data-scarce regions.
KW  - Amazon region
KW  - Complex terrain
KW  - South America
KW  - Streamflow
KW  - Precipitation
KW  - Hydrology
KW  - Water budget / balance
KW  - Inverse methods
KW  - Mountain meteorology
KW  - Machine learning
Y1  - 2022
U6  - https://doi.org/10.1175/JHM-D-20-0285.1
SN  - 1525-755X
SN  - 1525-7541
VL  - 23
IS  - 3
SP  - 309
EP  - 336
PB  - American Meteorological Soc.
CY  - Boston
ER  - 
TY  - JOUR
A1  - Ben Nsir, Siwar
A1  - Jomaa, Seifeddine
A1  - Yildirim, Umit
A1  - Zhou, Xiangqian
A1  - D'Oria, Marco
A1  - Rode, Michael
A1  - Khlifi, Slaheddine
T1  - Assessment of climate change impact on discharge of the lakhmass catchment (Northwest Tunisia)
JF  - Water
N2  - The Mediterranean region is increasingly recognized as a climate change hotspot but is highly underrepresented in hydrological climate change studies. This study aims to investigate the climate change effects on the hydrology of Lakhmass catchment in Tunisia. Lakhmass catchment is a part of the Medium Valley of Medjerda in northwestern Tunisia that drains an area of 126 km(2). First, the Hydrologiska Byrans Vattenbalansavdelning light (HBV-light) model was calibrated and validated successfully at a daily time step to simulate discharge during the 1981-1986 period. The Nash Sutcliffe Efficiency and Percent bias (NSE, PBIAS) were (0.80, +2.0%) and (0.53, -9.5%) for calibration (September 1982-August 1984) and validation (September 1984-August 1986) periods, respectively. Second, HBV-light model was considered as a predictive tool to simulate discharge in a baseline period (1981-2009) and future projections using data (precipitation and temperature) from thirteen combinations of General Circulation Models (GCMs) and Regional Climatic Models (RCMs). We used two trajectories of Representative Concentration Pathways, RCP4.5 and RCP8.5, suggested by the Intergovernmental Panel on Climate Change (IPCC). Each RCP is divided into three projection periods: near-term (2010-2039), mid-term (2040-2069) and long-term (2070-2099). For both scenarios, a decrease in precipitation and discharge will be expected with an increase in air temperature and a reduction in precipitation with almost 5% for every +1 degrees C of global warming. By long-term (2070-2099) projection period, results suggested an increase in temperature with about 2.7 degrees C and 4 degrees C, and a decrease in precipitation of approximately 7.5% and 15% under RCP4.5 and RCP8.5, respectively. This will likely result in a reduction of discharge of 12.5% and 36.6% under RCP4.5 and RCP8.5, respectively. This situation calls for early climate change adaptation measures under a participatory approach, including multiple stakeholders and water users.
KW  - hydrological modeling
KW  - HBV-light model
KW  - Mediterranean
KW  - discharge
KW  - climate change
KW  - RCP4,5 and 8,5
Y1  - 2022
U6  - https://doi.org/10.3390/w14142242
SN  - 2073-4441
VL  - 14
IS  - 14
PB  - MDPI
CY  - Basel
ER  - 
TY  - JOUR
A1  - McCool, Weston C.
A1  - Codding, Brian F.
A1  - Vernon, Kenneth B.
A1  - Wilson, Kurt M.
A1  - Yaworsky, Peter M.
A1  - Marwan, Norbert
A1  - Kennett, Douglas J.
T1  - Climate change-induced population pressure drives high rates of lethal violence in the Prehispanic central Andes
JF  - Proceedings of the National Academy of Sciences of the United States of America : PNAS
N2  - Understanding the influence of climate change and population pressure on human conflict remains a critically important topic in the social sciences. Long-term records that evaluate these dynamics across multiple centuries and outside the range of modern climatic variation are especially capable of elucidating the relative effect of-and the interaction between-climate and demography. This is crucial given that climate change may structure population growth and carrying capacity, while both climate and population influence per capita resource availability. This study couples paleoclimatic and demographic data with osteological evaluations of lethal trauma from 149 directly accelerator mass spectrometry C-14-dated individuals from the Nasca highland region of Peru. Multiple local and supraregional precipitation proxies are combined with a summed probability distribution of 149 C-14 dates to estimate population dynamics during a 700-y study window. Counter to previous findings, our analysis reveals a precipitous increase in violent deaths associated with a period of productive and stable climate, but volatile population dynamics. We conclude that favorable local climate conditions fostered population growth that put pressure on the marginal and highly circumscribed resource base, resulting in violent resource competition that manifested in over 450 y of internecine warfare. These findings help support a general theory of intergroup violence, indicating that relative resource scarcity-whether driven by reduced resource abundance or increased competition-can lead to violence in subsistence societies when the outcome is lower per capita resource availability.
KW  - climate change
KW  - population pressure
KW  - warfare
KW  - lethal violence
KW  - Andes
Y1  - 2022
U6  - https://doi.org/10.1073/pnas.2117556119
SN  - 0027-8424
SN  - 1091-6490
VL  - 119
IS  - 17
PB  - National Acad. of Sciences
CY  - Washington
ER  - 
TY  - JOUR
A1  - Gomez Zapata, Juan Camilo
A1  - Zafrir, Raquel
A1  - Pittore, Massimiliano
A1  - Merino, Yvonne
T1  - Towards a sensitivity analysis in seismic risk with probabilistic building exposure models
BT  - an application in Valparaiso, Chile using ancillary open-source data and parametric ground motions
JF  - ISPRS International Journal of Geo-Information
N2  - Efforts have been made in the past to enhance building exposure models on a regional scale with increasing spatial resolutions by integrating different data sources. This work follows a similar path and focuses on the downscaling of the existing SARA exposure model that was proposed for the residential building stock of the communes of Valparaiso and Vina del Mar (Chile). Although this model allowed great progress in harmonising building classes and characterising their differential physical vulnerabilities, it is now outdated, and in any case, it is spatially aggregated over large administrative units. Hence, to more accurately consider the impact of future earthquakes on these cities, it is necessary to employ more reliable exposure models. For such a purpose, we propose updating this existing model through a Bayesian approach by integrating ancillary data that has been made increasingly available from Volunteering Geo-Information (VGI) activities. Its spatial representation is also optimised in higher resolution aggregation units that avoid the inconvenience of having incomplete building-by-building footprints. A worst-case earthquake scenario is presented to calculate direct economic losses and highlight the degree of uncertainty imposed by exposure models in comparison with other parameters used to generate the seismic ground motions within a sensitivity analysis. This example study shows the great potential of using increasingly available VGI to update worldwide building exposure models as well as its importance in scenario-based seismic risk assessment.
KW  - exposure
KW  - buildings
KW  - Bayesian model
KW  - downscaling
KW  - OpenStreetMap
KW  - ground motion fields
KW  - sensitivity
KW  - earthquake
KW  - vulnerability
KW  - risk
Y1  - 2022
U6  - https://doi.org/10.3390/ijgi11020113
SN  - 2220-9964
VL  - 11
IS  - 2
PB  - MDPI
CY  - Basel
ER  - 
TY  - JOUR
A1  - Melchert, Jan Olaf
A1  - Wischhöfer, Philipp
A1  - Knoblauch, Christian
A1  - Eckhardt, Tim
A1  - Liebner, Susanne
A1  - Rethemeyer, Janet
T1  - Sources of CO2 Produced in Freshly Thawed Pleistocene-Age Yedoma Permafrost
JF  - Frontiers in Earth Science
N2  - The release of greenhouse gases from the large organic carbon stock in permafrost deposits in the circumarctic regions may accelerate global warming upon thaw. The extent of this positive climate feedback is thought to be largely controlled by the microbial degradability of the organic matter preserved in these sediments. In addition, weathering and oxidation processes may release inorganic carbon preserved in permafrost sediments as CO2, which is generally not accounted for. We used C-13 and C-14 analysis and isotopic mass balances to differentiate and quantify organic and inorganic carbon released as CO2 in the field from an active retrogressive thaw slump of Pleistocene-age Yedoma and during a 1.5-years incubation experiment. The results reveal that the dominant source of the CO2 released from freshly thawed Yedoma exposed as thaw mound is Pleistocene-age organic matter (48-80%) and to a lesser extent modern organic substrate (3-34%). A significant portion of the CO2 originated from inorganic carbon in the Yedoma (17-26%). The mixing of young, active layer material with Yedoma at a site on the slump floor led to the preferential mineralization of this young organic carbon source. Admixtures of younger organic substrates in the Yedoma thaw mound were small and thus rapidly consumed as shown by lower contributions to the CO2 produced during few weeks of aerobic incubation at 4 degrees C corresponding to approximately one thaw season. Future CO2 fluxes from the freshly thawed Yedoma will contain higher proportions of ancient inorganic (22%) and organic carbon (61-78%) as suggested by the results at the end, after 1.5 years of incubation. The increasing contribution of inorganic carbon during the incubation is favored by the accumulation of organic acids from microbial organic matter degradation resulting in lower pH values and, in consequence, in inorganic carbon dissolution. Because part of the inorganic carbon pool is assumed to be of pedogenic origin, these emissions would ultimately not alter carbon budgets. The results of this study highlight the preferential degradation of younger organic substrates in freshly thawed Yedoma, if available, and a substantial release of CO2 from inorganic sources.
KW  - yedoma ice complex
KW  - permafost
KW  - carbon cycle
KW  - climat change
KW  - thermokarst
KW  - radiocarbon
KW  - greenhouse gas
Y1  - 2022
U6  - https://doi.org/10.3389/feart.2021.737237
SN  - 2296-6463
VL  - 9
PB  - Frontiers Media
CY  - Lausanne
ER  - 
TY  - JOUR
A1  - West, Charles
A1  - Rosolem, Rafael
A1  - MacDonald, Alan M.
A1  - Cuthbert, Mark O.
A1  - Wagener, Thorsten
T1  - Understanding process controls on groundwater recharge variability across Africa through recharge landscapes
JF  - Journal of hydrology
N2  - Groundwater is critical in supporting current and future reliable water supply throughout Africa. Although continental maps of groundwater storage and recharge have been developed, we currently lack a clear understanding on how the controls on groundwater recharge vary across the entire continent. Reviewing the existing literature, we synthesize information on reported groundwater recharge controls in Africa. We find that 15 out of 22 of these controls can be characterised using global datasets. We develop 11 descriptors of climatic, topographic, vegetation, soil and geologic properties using global datasets, to characterise groundwater recharge controls in Africa. These descriptors cluster Africa into 15 Recharge Landscape Units for which we expect recharge controls to be similar. Over 80% of the continents land area is organized by just nine of these units. We also find that aggregating the Units by similarity into four broader Recharge Landscapes (Desert, Dryland, Wet tropical and Wet tropical forest) provides a suitable level of landscape organisation to explain differences in ground-based long-term mean annual recharge and recharge ratio (annual recharge / annual precipitation) estimates. Furthermore, wetter Recharge Landscapes are more efficient in converting rainfall to recharge than drier Recharge Landscapes as well as having higher annual recharge rates. In Dryland Recharge Landscapes, we found that annual recharge rates largely varied according to mean annual precipitation, whereas recharge ratio estimates increase with increasing monthly variability in P-PET. However, we were unable to explain why ground based estimates of recharge signatures vary across other Recharge Landscapes, in which there are fewer ground based recharge estimates, using global datasets alone. Even in dryland regions, there is still considerable unexplained variability in the estimates of annual recharge and recharge ratio, stressing the limitations of global datasets for investigating ground-based information.
KW  - Groundwater recharge
KW  - Africa
KW  - Recharge controls
KW  - Ground-based estimates
KW  - Landscapes
KW  - Comparative hydrology
Y1  - 2022
U6  - https://doi.org/10.1016/j.jhydrol.2022.127967
SN  - 0022-1694
SN  - 1879-2707
VL  - 612
PB  - Elsevier
CY  - Amsterdam
ER  - 
TY  - JOUR
A1  - Kotha, Sreeram Reddy
A1  - Weatherill, Graeme
A1  - Bindi, Dino
A1  - Cotton, Fabrice
T1  - Near-source magnitude scaling of spectral accelerations
BT  - analysis and update of Kotha et al. (2020) model
JF  - Bulletin of earthquake engineering : official publication of the European Association for Earthquake Engineering
N2  - Ground-motion models (GMMs) are often used to predict the random distribution of Spectral accelerations (SAs) at a site due to a nearby earthquake. In probabilistic seismic hazard and risk assessment, large earthquakes occurring close to a site are considered as critical scenarios. GMMs are expected to predict realistic SAs with low within-model uncertainty (sigma(mu)) for such rare scenarios. However, the datasets used to regress GMMs are usually deficient of data from critical scenarios. The (Kotha et al., A Regionally Adaptable Ground-Motion Model for Shallow Crustal Earthquakes in Europe Bulletin of Earthquake Engineering 18:4091-4125, 2020) GMM developed from the Engineering strong motion (ESM) dataset was found to predict decreasing short-period SAs with increasing M-W >= M-h = 6.2, and with large sigma(mu) at near-source distances <= 30km. In this study, we updated the parametrisation of the GMM based on analyses of ESM and the Near source strong motion (NESS) datasets. With M-h = 5.7, we could rectify the M-W scaling issue, while also reducing sigma(mu). at M-W >= M-h. We then evaluated the GMM against NESS data, and found that the SAs from a few large, thrust-faulting events in California, New Zealand, Japan, and Mexico are significantly higher than GMM median predictions. However, recordings from these events were mostly made on soft-soil geology, and contain anisotropic pulse-like effects. A more thorough non-ergodic treatment of NESS was not possible because most sites sampled unique events in very diverse tectonic environments. We provide an updated set of GMM coefficients,sigma(mu), and heteroscedastic variance models; while also cautioning against its application for M-W <= 4 in low-moderate seismicity regions without evaluating the homogeneity of M-W estimates between pan-European ESM and regional datasets.
KW  - Ground-motion model
KW  - Spectral accelerations
KW  - Magnitude scalin
KW  - Near-source saturation
KW  - Within-model uncertainty
KW  - Heteroscedastic
KW  - variability
Y1  - 2022
U6  - https://doi.org/10.1007/s10518-021-01308-5
SN  - 1570-761X
SN  - 1573-1456
VL  - 20
IS  - 3
SP  - 1343
EP  - 1370
PB  - Springer
CY  - Dordrecht
ER  - 
TY  - JOUR
A1  - Peña, Carlos
A1  - Metzger, Sabrina
A1  - Heidbach, Oliver
A1  - Bedford, Jonathan
A1  - Bookhagen, Bodo
A1  - Moreno, Marcos
A1  - Oncken, Onno
A1  - Cotton, Fabrice
T1  - Role of poroelasticity during the early postseismic deformation of the 2010 Maule megathrust earthquake
JF  - Geophysical research letters
N2  - Megathrust earthquakes impose changes of differential stress and pore pressure in the lithosphere-asthenosphere system that are transiently relaxed during the postseismic period primarily due to afterslip, viscoelastic and poroelastic processes. 
Especially during the early postseismic phase, however, the relative contribution of these processes to the observed surface deformation is unclear. 
To investigate this, we use geodetic data collected in the first 48 days following the 2010 Maule earthquake and a poro-viscoelastic forward model combined with an afterslip inversion. 
This model approach fits the geodetic data 14% better than a pure elastic model. Particularly near the region of maximum coseismic slip, the predicted surface poroelastic uplift pattern explains well the observations. 
If poroelasticity is neglected, the spatial afterslip distribution is locally altered by up to +/- 40%. 
Moreover, we find that shallow crustal aftershocks mostly occur in regions of increased postseismic pore-pressure changes, indicating that both processes might be mechanically coupled.
KW  - Chilean subduction zone
KW  - poroelasticity
KW  - power-law rheology
KW  - afterslip inversion
KW  - InSAR
KW  - GNSS
Y1  - 2022
U6  - https://doi.org/10.1029/2022GL098144
SN  - 0094-8276
SN  - 1944-8007
VL  - 49
IS  - 9
PB  - Wiley
CY  - Hoboken, NJ
ER  - 
TY  - JOUR
A1  - Sarrazin, Fanny J.
A1  - Kumar, Rohini
A1  - Basu, Nandita B.
A1  - Musolff, Andreas
A1  - Weber, Michael
A1  - Van Meter, Kimberly J.
A1  - Attinger, Sabine
T1  - Characterizing catchment-scale nitrogen legacies and constraining their uncertainties
JF  - Water resources research
N2  - Improving nitrogen (N) status in European water bodies is a pressing issue. N levels depend not only on current but also past N inputs to the landscape, that have accumulated through time in legacy stores (e.g., soil, groundwater). 
Catchment-scale N models, that are commonly used to investigate in-stream N levels, rarely examine the magnitude and dynamics of legacy components. 

This study aims to gain a better understanding of the long-term fate of the N inputs and its uncertainties, using a legacy-driven N model (ELEMeNT) in Germany's largest national river basin (Weser; 38,450 km(2)) over the period 1960-2015. 
We estimate the nine model parameters based on a progressive constraining strategy, to assess the value of different observational data sets. 
We demonstrate that beyond in-stream N loading, soil N content and in-stream N concentration allow to reduce the equifinality in model parameterizations. 
We find that more than 50% of the N surplus denitrifies (1480-2210 kg ha(-1)) and the stream export amounts to around 18% (410-640 kg ha(-1)), leaving behind as much as around 230-780 kg ha(-1) of N in the (soil) source zone and 10-105 kg ha(-1) in the subsurface. 

A sensitivity analysis reveals the importance of different factors affecting the residual uncertainties in simulated N legacies, namely hydrologic travel time, denitrification rates, a coefficient characterizing the protection of organic N in source zone and N surplus input. 

Our study calls for proper consideration of uncertainties in N legacy characterization, and discusses possible avenues to further reduce the equifinality in water quality modeling.
KW  - nitrogen legacies
KW  - water quality modeling
KW  - equifinality
KW  - parameter
KW  - estimation
KW  - sensitivity analysis
Y1  - 2022
U6  - https://doi.org/10.1029/2021WR031587
SN  - 0043-1397
SN  - 1944-7973
VL  - 58
IS  - 4
PB  - American Geophysical Union
CY  - Washington
ER  - 
TY  - CHAP
A1  - Cárdenas, Aura
A1  - Schernthanner, Harald
ED  - Jacob-Lopes, Eduardo
ED  - Queiroz Zepka, Leila
ED  - Costa Deprá, Mariany
T1  - The role of livestock wastes in clean energy
BT  - a mapping in Germany’s potential installations
T2  - Handbook of waste biorefinery
N2  - Agricultural production worldwide has been increasing in the last decades at a very fast pace and with it the waste generation. Livestock activities are one of the largest producers of residues in the agricultural sector and contribute greatly to climate change. The present chapter gives an introduction and an in-depth analysis of the waste management of livestock for the conversion in a circular agriculture and economy based on research and experience in the sector conducted in the last decades. The conversion of animal waste into energy generation is an opportunity for farmers to obtain additional economic benefits, while contributing to the environment by preventing the release of GHGs into the atmosphere. The use of animal waste for energy generation through anaerobic digestion is a progressive technique and is being widely accepted in Europe, where Germany is the leading country in the use of biogas plants for energy production among others in the European Union. Economically speaking, the livestock industry faces the challenge of converting its production into a clean and more profitable production. The goal of this chapter is to analyze the economic benefit as well as the environmental contribution and future challenges of the use of livestock waste in the biorefineries sector from different perspectives, based on an intensive literature review. This review is accompanied by a geospatial analysis component, mapping biogas reactor hotspots and clusters in Germany, by means of methods of spatial statistics as analysis methods as kernel density estimations (KDE) and K-means clustering, based on volunteer geographic data. The applied methods easily can be transferred to other regions and allow a quick macroscopic overview over existing biogas reactors; furthermore, an identification of cluster and hotspots with a high biogas potential, that in a subsequent step can be analyzed in depth in larger scales.
Y1  - 2022
SN  - 978-3-031-06561-3
U6  - https://doi.org/10.1007/978-3-031-06562-0_12
SP  - 337
EP  - 343
PB  - Springer
CY  - Cham
ER  - 
TY  - JOUR
A1  - Zuhr, Alexandra M.
A1  - Dolman, Andrew M.
A1  - Ho, Sze Ling
A1  - Groeneveld, Jeroen
A1  - Loewemark, Ludvig
A1  - Grotheer, Hendrik
A1  - Su, Chih-Chieh
A1  - Laepple, Thomas
T1  - Age-heterogeneity in marine sediments revealed by three-dimensional high-resolution radiocarbon measurements
JF  - Frontiers in Earth Science
N2  - Marine sedimentary archives are routinely used to reconstruct past environmental changes. In many cases, bioturbation and sedimentary mixing affect the proxy time-series and the age-depth relationship. While idealized models of bioturbation exist, they usually assume homogeneous mixing, thus that a single sample is representative for the sediment layer it is sampled from. 

However, it is largely unknown to which extent this assumption holds for sediments used for paleoclimate reconstructions. 
To shed light on 
1) the age-depth relationship and its full uncertainty, 
2) the magnitude of mixing processes affecting the downcore proxy variations, and 
3) the representativity of the discrete sample for the sediment layer, we designed and performed a case study on South China Sea sediment material which was collected using a box corer and which covers the last glacial cycle. 

Using the radiocarbon content of foraminiferal tests as a tracer of time, we characterize the spatial age-heterogeneity of sediments in a three-dimensional setup. In total, 118 radiocarbon measurements were performed on defined small- and large-volume bulk samples ( similar to 200 specimens each) to investigate the horizontal heterogeneity of the sediment. Additionally, replicated measurements on small numbers of specimens (10 x 5 specimens) were performed to assess the heterogeneity within a sample volume. Visual assessment of X-ray images and a quantitative assessment of the mixing strength show typical mixing from bioturbation corresponding to around 10 cm mixing depth. 

Notably, our 3D radiocarbon distribution reveals that the horizontal heterogeneity (up to 1,250 years), contributing to the age uncertainty, is several times larger than the typically assumed radiocarbon based age-model error (single errors up to 250 years). Furthermore, the assumption of a perfectly bioturbated layer with no mixing underneath is not met. 

Our analysis further demonstrates that the age-heterogeneity might be a function of sample size; smaller samples might contain single features from the incomplete mixing and are thus less representative than larger samples. 
We provide suggestions for future studies, optimal sampling strategies for quantitative paleoclimate reconstructions and realistic uncertainty in age models, as well as discuss possible implications for the interpretation of paleoclimate records.
KW  - paleoceanography
KW  - radiocarbon
KW  - age-heterogeneity
KW  - marine sediments
KW  - planktonic foraminifera
KW  - bioturbation
KW  - agemodeling
KW  - South China Sea
Y1  - 2022
U6  - https://doi.org/10.3389/feart.2022.871902
SN  - 2296-6463
VL  - 10
PB  - Frontiers Media
CY  - Lausanne
ER  - 
TY  - JOUR
A1  - Rodriguez, Victoria
A1  - Moskwa, Lisa-Marie
A1  - Oses, Romulo
A1  - Kühn, Peter
A1  - Riveras-Muñoz, Nicolás
A1  - Seguel, Oscar
A1  - Scholten, Thomas
A1  - Wagner, Dirk
T1  - Impact of climate and slope aspects on the composition of soil bacterial communities involved in pedogenetic processes along the chilean coastal cordillera
JF  - Microorganisms
N2  - Soil bacteria play a fundamental role in pedogenesis. However, knowledge about both the impact of climate and slope aspects on microbial communities and the consequences of these items in pedogenesis is lacking. Therefore, soil-bacterial communities from four sites and two different aspects along the climate gradient of the Chilean Coastal Cordillera were investigated. Using a combination of microbiological and physicochemical methods, soils that developed in arid, semi-arid, mediterranean, and humid climates were analyzed. Proteobacteria, Acidobacteria, Chloroflexi, Verrucomicrobia, and Planctomycetes were found to increase in abundance from arid to humid climates, while Actinobacteria and Gemmatimonadetes decreased along the transect. Bacterial-community structure varied with climate and aspect and was influenced by pH, bulk density, plant-available phosphorus, clay, and total organic-matter content. Higher bacterial specialization was found in arid and humid climates and on the south-facing slope and was likely promoted by stable microclimatic conditions. The presence of specialists was associated with ecosystem-functional traits, which shifted from pioneers that accumulated organic matter in arid climates to organic decomposers in humid climates. These findings provide new perspectives on how climate and slope aspects influence the composition and functional capabilities of bacteria, with most of these capabilities being involved in pedogenetic processes.
KW  - bacterial-community structure
KW  - bacterial diversity
KW  - climate gradient
KW  - slope aspect
KW  - Chilean Coastal Cordillera
KW  - soil formation
Y1  - 2022
U6  - https://doi.org/10.3390/microorganisms10050847
SN  - 2076-2607
VL  - 10
IS  - 5
PB  - MDPI
CY  - Basel
ER  - 
TY  - JOUR
A1  - Illien, Luc
A1  - Sens-Schönfelder, Christoph
A1  - Andermann, Christoff
A1  - Marc, Odin
A1  - Cook, Kristen L.
A1  - Adhikari, Lok Bijaya
A1  - Hovius, Niels
T1  - Seismic velocity recovery in the subsurface
BT  - transient damage and groundwater drainage following the 2015 Gorkha Earthquake, Nepal
JF  - Journal of geophysical research : Solid earth
N2  - Shallow earthquakes frequently disturb the hydrological and mechanical state of the subsurface, with consequences for hazard and water management. Transient post-seismic hydrological behavior has been widely reported, suggesting that the recovery of material properties (relaxation) following ground shaking may impact groundwater fluctuations. However, the monitoring of seismic velocity variations associated with earthquake damage and hydrological variations are often done assuming that both effects are independent. In a field site prone to highly variable hydrological conditions, we disentangle the different forcing of the relative seismic velocity variations delta v retrieved from a small dense seismic array in Nepal in the aftermath of the 2015 M-w 7.8 Gorkha earthquake. We successfully model transient damage effects by introducing a universal relaxation function that contains a unique maximum relaxation timescale for the main shock and the aftershocks, independent of the ground shaking levels. Next, we remove the modeled velocity from the raw data and test whether the corresponding residuals agree with a background hydrological behavior we inferred from a previously calibrated groundwater model. The fitting of the delta v data with this model is improved when we introduce transient hydrological properties in the phase immediately following the main shock. This transient behavior, interpreted as an enhanced permeability in the shallow subsurface, lasts for similar to 6 months and is shorter than the damage relaxation (similar to 1 yr). Thus, we demonstrate the capability of seismic interferometry to deconvolve transient hydrological properties after earthquakes from non-linear mechanical recovery.
KW  - earthquake damage
KW  - earthquake hydrology
KW  - relaxation
KW  - Gorkha earthquake
KW  - seismic monitoring
KW  - ambient noise
Y1  - 2022
U6  - https://doi.org/10.1029/2021JB023402
SN  - 2169-9313
SN  - 2169-9356
VL  - 127
IS  - 2
PB  - American Geophysical Union
CY  - Washington
ER  - 
TY  - JOUR
A1  - Katzenberger, Anja
A1  - Levermann, Anders
A1  - Schewe, Jacob
A1  - Pongratz, Julia
T1  - Intensification of very wet monsoon seasons in India under global warming
JF  - Geophysical research letters
N2  - Rainfall-intense summer monsoon seasons on the Indian subcontinent that are exceeding long-term averages cause widespread floods and landslides. 

Here we show that the latest generation of coupled climate models robustly project an intensification of very rainfall-intense seasons (June-September). 
Under the shared socioeconomic pathway SSP5-8.5, very wet monsoon seasons as observed in only 5 years in the period 1965-2015 are projected to occur 8 times more often in 2050-2100 in the multi-model average. 

Under SSP2-4.5, these seasons become only a factor of 6 times more frequent, showing that even modest efforts to mitigate climate change can have a strong impact on the frequency of very strong rainfall seasons. 

Besides, we find that the increasing risk of extreme seasonal rainfall is accompanied by a shift from days with light rainfall to days with moderate or heavy rainfall. Additionally, the number of wet days is projected to increase.
KW  - Indian monsoon
KW  - climate modeling
KW  - extreme seasons
KW  - climate change
KW  - CMIP6
KW  - India
Y1  - 2022
U6  - https://doi.org/10.1029/2022GL098856
SN  - 0094-8276
SN  - 1944-8007
VL  - 49
IS  - 15
PB  - American Geophysical Union
CY  - Washington
ER  - 
TY  - JOUR
A1  - Dey, Somnath
A1  - Schönleber, Andreas
A1  - Smaalen, Sander van
A1  - Morgenroth, Wolfgang
A1  - Larsen, Finn Krebs
T1  - Incommensurate phase in Λ-cobalt (III) sepulchrate trinitrate governed by highly competitive N-H...O and C-H...O hydrogen bond networks
JF  - Chemistry - a European journal
N2  - Phase transitions in molecular crystals are often determined by intermolecular interactions. The cage complex of [Co(C12H30N8)](3+) . 3 NO3- is reported to undergo a disorder-order phase transition at T-c1 approximate to 133 K upon cooling. Temperature-dependent neutron and synchrotron diffraction experiments revealed satellite reflections in addition to main reflections in the diffraction patterns below T-c1. The modulation wave vector varies as function of temperature and locks in at T-c3 approximate to 98 K. Here, we demonstrate that the crystal symmetry lowers from hexagonal to monoclinic in the incommensurately modulated phases in T-c1<T<T-c3. Distinctive levels of competitions: trade-off between longer N-H...O and shorter C-H...O hydrogen bonds; steric constraints to dense C-H...O bonds give rise to pronounced modulation of the basic structure. Severely frustrated crystal packing in the incommensurate phase is precursor to optimal balance of intermolecular interactions in the lock-in phase.
KW  - hydrogen bond
KW  - incommensurate modulation
KW  - phase transition
KW  - steric factors
KW  - twin domains
Y1  - 2022
U6  - https://doi.org/10.1002/chem.202104151
SN  - 0947-6539
SN  - 1521-3765
VL  - 28
IS  - 13
PB  - Wiley-VCH
CY  - Weinheim
ER  - 
TY  - THES
A1  - Siegmund, Nicole
T1  - Wind driven soil particle uptake Quantifying drivers of wind erosion across the particle size spectrum
T1  - Partikelaufwirbelung durch Wind - Über die Quantifizierung von Winderosion über das ganze Partikel-Größenspektrum
N2  - Among the multitude of geomorphological processes, aeolian shaping processes are of special character, Pedogenic dust is one of the most important sources of atmospheric aerosols and therefore regarded as a key player for atmospheric processes. Soil dust emissions, being complex in composition and properties, influence atmospheric processes and air quality and has impacts on other ecosystems. In this because even though their immediate impact can be considered low (exceptions exist), their constant and large-scale force makes them a powerful player in the earth system. dissertation, we unravel a novel scientific understanding of this complex system based on a holistic dataset acquired during a series of field experiments on arable land in La Pampa, Argentina. The field experiments as well as the generated data provide information about topography, various soil parameters, the atmospheric dynamics in the very lower atmosphere (4m height) as well as measurements regarding aeolian particle movement across a wide range of particle size classes between 0.2μm up to the coarse sand. 
The investigations focus on three topics: (a) the effects of low-scale landscape structures on aeolian transport processes of the coarse particle fraction, (b) the horizontal and vertical fluxes of the very fine particles and (c) the impact of wind gusts on particle emissions. 
Among other considerations presented in this thesis, it could in particular be shown, that even though the small-scale topology does have a clear impact on erosion and deposition patterns, also physical soil parameters need to be taken into account for a robust statistical modelling of the latter. Furthermore, specifically the vertical fluxes of particulate matter have different characteristics for the particle size classes. Finally, a novel statistical measure was introduced to quantify the impact of wind gusts on the particle uptake and its application on the provided data set. The aforementioned measure shows significantly increased particle concentrations during points in time defined as gust event. 
With its holistic approach, this thesis further contributes to the fundamental understanding of how atmosphere and pedosphere are intertwined and affect each other.
N2  - Unter der Vielzahl geomorphologischer Prozesse nehmen äolische Formgebungsprozesse eine besondere Stellung ein, denn obwohl ihre unmittelbaren Auswirkungen als gering einzuschätzen sind (Ausnahmen existieren), sind sie aufgrund ihrer konstanten und großen Kraft ein mächtiger Akteur im Erdsystem. Pedogener Staub ist eine der wichtigsten Quellen atmosphärischer Aerosole und kann daher als Schlüsselfaktor für atmosphärische Prozesse angesehen werden. 
Bodenstaubemissionen, die in Zusammensetzung und Eigenschaften komplex sind, beeinflussen atmosphärische Prozesse und Luftqualität und haben Auswirkungen auf andere Ökosysteme. Um zum wissenschaftlichen Verständnis dieses komplexen Systems beizutragen, dokumentiert diese Arbeit eine Reihe von Veröffentlichungen, die alle auf einem ganzheitlichen Datensatz basieren, die während einer Reihe von Feldexperimenten auf Ackerland in La Pampa, Argentinien, gewonnen wurden. Die Feldexperimente sowie die generierten Daten liefern Informationen über Topographie, verschiedene Bodenparameter, die atmosphärische Dynamik in der unteren Atmosphäre (4 m Höhe) sowie Messungen zur äolischen Partikelbewegung über einen weiten Bereich von Partikelgrößenklassen zwischen 0,2μm und groben Sand. 
Die Untersuchungen konzentrieren sich auf drei Themen: Die Auswirkungen kleinräumiger Landschaftsstrukturen auf äolische Transportprozesse der groben Partikelfraktion, die horizontalen und vertikalen Strömungen der sehr feinen Partikel und der Einfluss von Windböen auf die Partikelemissionen. 
Neben anderen in dieser Arbeit vorgestellten Überlegungen konnte insbesondere gezeigt werden, dass, obwohl die kleinräumige Topologie einen deutlichen Einfluss auf Erosions- und Ablagerungsmuster hat, auch physikalische Bodenparameter für eine robuste statistische Modellierung berücksichtigt werden müssen. Darüber hinaus weisen speziell die vertikalen Feinstaubflüsse unterschiedliche Eigenschaften für die Partikelgrößenklassen auf. Schließlich wurde ein neuartiges statistisches Maß eingeführt, um den Einfluss von Windböen auf die Partikelkonzentration der Luft zu quantifizieren, und seine Anwendung auf den bereitgestellten Datensatz zeigt signifikant erhöhte Partikelkonzentrationen zu Zeitpunkten, die als Böen definiert wurden. Mit ihrem ganzheitlichen Ansatz trägt diese Arbeit weiter zum grundlegenden Verständnis bei, wie Atmosphäre und Pedosphäre miteinander verflochten sind und sich gegenseitig beeinflussen.
KW  - Winderosion
KW  - winderosion
KW  - PM10, PM2, PM1
KW  - Horizontal flux
KW  - horizontaler Fluss
KW  - Vertical flux
KW  - vertikaler Fluss
KW  - Argentina
KW  - Argentinien
KW  - wind gusts
KW  - Windböen
Y1  - 2022
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-574897
ER  - 
TY  - JOUR
A1  - Trauth, Martin H.
A1  - Marwan, Norbert
T1  - Introduction-time series analysis for Earth, climate and life interactions
JF  - Quaternary science reviews : the international multidisciplinary research and review journal
Y1  - 2022
U6  - https://doi.org/10.1016/j.quascirev.2022.107475
SN  - 0277-3791
SN  - 1873-457X
VL  - 284
PB  - Elsevier
CY  - Amsterdam [u.a.]
ER  - 
TY  - GEN
A1  - Heistermann, Maik
A1  - Bogena, Heye
A1  - Francke, Till
A1  - Güntner, Andreas
A1  - Jakobi, Jannis
A1  - Rasche, Daniel
A1  - Schrön, Martin
A1  - Döpper, Veronika
A1  - Fersch, Benjamin
A1  - Groh, Jannis
A1  - Patil, Amol
A1  - Pütz, Thomas
A1  - Reich, Marvin
A1  - Zacharias, Steffen
A1  - Zengerle, Carmen
A1  - Oswald, Sascha
T1  - Soil moisture observation in a forested headwater catchment: combining a dense cosmic-ray neutron sensor network with roving and hydrogravimetry at the TERENO site Wüstebach
T2  - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe
N2  - Cosmic-ray neutron sensing (CRNS) has become an effective method to measure soil moisture at a horizontal scale of hundreds of metres and a depth of decimetres. Recent studies proposed operating CRNS in a network with overlapping footprints in order to cover root-zone water dynamics at the small catchment scale and, at the same time, to represent spatial heterogeneity. In a joint field campaign from September to November 2020 (JFC-2020), five German research institutions deployed 15 CRNS sensors in the 0.4 km2 Wüstebach catchment (Eifel mountains, Germany). The catchment is dominantly forested (but includes a substantial fraction of open vegetation) and features a topographically distinct catchment boundary. In addition to the dense CRNS coverage, the campaign featured a unique combination of additional instruments and techniques: hydro-gravimetry (to detect water storage dynamics also below the root zone); ground-based and, for the first time, airborne CRNS roving; an extensive wireless soil sensor network, supplemented by manual measurements; and six weighable lysimeters. Together with comprehensive data from the long-term local research infrastructure, the published data set (available at https://doi.org/10.23728/b2share.756ca0485800474e9dc7f5949c63b872; Heistermann et al., 2022) will be a valuable asset in various research contexts: to advance the retrieval of landscape water storage from CRNS, wireless soil sensor networks, or hydrogravimetry; to identify scale-specific combinations of sensors and methods to represent soil moisture variability; to improve the understanding and simulation of land–atmosphere exchange as well as hydrological and hydrogeological processes at the hillslope and the catchment scale; and to support the retrieval of soil water content from airborne and spaceborne remote sensing platforms.
T3  - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 1272 
Y1  - 2022
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-567756
SN  - 1866-8372
IS  - 1272
SP  - 2501
EP  - 2519
ER  - 
TY  - JOUR
A1  - Agarwal, Ankit
A1  - Guntu, Ravikumar
A1  - Banerjee, Abhirup
A1  - Gadhawe, Mayuri Ashokrao
A1  - Marwan, Norbert
T1  - A complex network approach to study the extreme precipitation patterns in a river basin
JF  - Chaos : an interdisciplinary journal of nonlinear science
N2  - The quantification of spatial propagation of extreme precipitation events is vital in water resources planning and disaster mitigation. However, quantifying these extreme events has always been challenging as many traditional methods are insufficient to capture the nonlinear interrelationships between extreme event time series. Therefore, it is crucial to develop suitable methods for analyzing the dynamics of extreme events over a river basin with a diverse climate and complicated topography. Over the last decade, complex network analysis emerged as a powerful tool to study the intricate spatiotemporal relationship between many variables in a compact way. In this study, we employ two nonlinear concepts of event synchronization and edit distance to investigate the extreme precipitation pattern in the Ganga river basin. We use the network degree to understand the spatial synchronization pattern of extreme rainfall and identify essential sites in the river basin with respect to potential prediction skills. The study also attempts to quantify the influence of precipitation seasonality and topography on extreme events. The findings of the study reveal that (1) the network degree is decreased in the southwest to northwest direction, (2) the timing of 50th percentile precipitation within a year influences the spatial distribution of degree, (3) the timing is inversely related to elevation, and (4) the lower elevation greatly influences connectivity of the sites. The study highlights that edit distance could be a promising alternative to analyze event-like data by incorporating event time and amplitude and constructing complex networks of climate extremes.
Y1  - 2022
U6  - https://doi.org/10.1063/5.0072520
SN  - 1054-1500
SN  - 1089-7682
VL  - 32
IS  - 1
PB  - American Institute of Physics
CY  - Woodbury, NY
ER  - 
TY  - JOUR
A1  - Kamjunke, Norbert
A1  - Beckers, Liza-Marie
A1  - Herzsprung, Peter
A1  - von Tümpling, Wolf
A1  - Lechtenfeld, Oliver
A1  - Tittel, Jörg
A1  - Risse-Buhl, Ute
A1  - Rode, Michael
A1  - Wachholz, Alexander
A1  - Kallies, Rene
A1  - Schulze, Tobias
A1  - Krauss, Martin
A1  - Brack, Werner
A1  - Comero, Sara
A1  - Gawlik, Bernd Manfred
A1  - Skejo, Hello
A1  - Tavazzi, Simona
A1  - Mariani, Giulio
A1  - Borchardt, Dietrich
A1  - Weitere, Markus
T1  - Lagrangian profiles of riverine autotrophy, organic matter transformation, and micropollutants at extreme drought
JF  - The science of the total environment : an international journal for scientific research into the environment and its relationship with man
N2  - On their way from inland to the ocean, flowing water bodies, their constituents and their biotic communities are ex-posed to complex transport and transformation processes. However, detailed process knowledge as revealed by La-grangian measurements adjusted to travel time is rare in large rivers, in particular at hydrological extremes. To fill this gap, we investigated autotrophic processes, heterotrophic carbon utilization, and micropollutant concentrations applying a Lagrangian sampling design in a 600 km section of the River Elbe (Germany) at historically low discharge. Under base flow conditions, we expect the maximum intensity of instream processes and of point source impacts. Phy-toplankton biomass and photosynthesis increased from upstream to downstream sites but maximum chlorophyll con-centration was lower than at mean discharge. Concentrations of dissolved macronutrients decreased to almost complete phosphate depletion and low nitrate values. The longitudinal increase of bacterial abundance and production was less pronounced than in wetter years and bacterial community composition changed downstream. Molecular analyses revealed a longitudinal increase of many DOM components due to microbial production, whereas saturated lipid-like DOM, unsaturated aromatics and polyphenols, and some CHOS surfactants declined. In decomposition exper-iments, DOM components with high O/C ratios and high masses decreased whereas those with low O/C ratios, low masses, and high nitrogen content increased at all sites. Radiocarbon age analyses showed that DOC was relatively old (890-1870 years B.P.), whereas the mineralized fraction was much younger suggesting predominant oxidation of algal lysis products and exudates particularly at downstream sites. Micropollutants determining toxicity for algae (terbuthylazine, terbutryn, isoproturon and lenacil), hexachlorocyclohexanes and DDTs showed higher concentrations from the middle towards the downstream part but calculated toxicity was not negatively correlated to phytoplankton. Overall, autotrophic and heterotrophic process rates and micropollutant concentrations increased from up-to down-stream reaches, but their magnitudes were not distinctly different to conditions at medium discharges.
KW  - Phytoplankton
KW  - Nutrients
KW  - Dissolved organic matter (DOM)
KW  - bacteria
KW  - Respiration
KW  - Micropollutants
Y1  - 2022
U6  - https://doi.org/10.1016/j.scitotenv.2022.154243
SN  - 0048-9697
SN  - 1879-1026
VL  - 828
PB  - Elsevier
CY  - Amsterdam
ER  - 
TY  - JOUR
A1  - Nagakura, Toshiki
A1  - Schubert, Florian
A1  - Wagner, Dirk
A1  - Kallmeyer, Jens
T1  - Biological sulfate reduction in deep subseafloor sediment of Guaymas Basin
JF  - Frontiers in microbiology
N2  - Sulfate reduction is the quantitatively most important process to degrade organic matter in anoxic marine sediment and has been studied intensively in a variety of settings. Guaymas Basin, a young marginal ocean basin, offers the unique opportunity to study sulfate reduction in an environment characterized by organic-rich sediment, high sedimentation rates, and high geothermal gradients (100-958 degrees C km(-1)). We measured sulfate reduction rates (SRR) in samples taken during the International Ocean Discovery Program (IODP) Expedition 385 using incubation experiments with radiolabeled (SO42-)-S-35 carried out at in situ pressure and temperature. The highest SRR (387 nmol cm(-3) d(-1)) was recorded in near-surface sediments from Site U1548C, which had the steepest geothermal gradient (958 degrees C km(-1)). At this site, SRR were generally over an order of magnitude higher than at similar depths at other sites (e.g., 387-157 nmol cm(-3) d(-1) at 1.9 mbsf from Site U1548C vs. 46-1.0 nmol cm(-3) d(-1) at 2.1 mbsf from Site U1552B). Site U1546D is characterized by a sill intrusion, but it had already reached thermal equilibrium and SRR were in the same range as nearby Site U1545C, which is minimally affected by sills. The wide temperature range observed at each drill site suggests major shifts in microbial community composition with very different temperature optima but awaits confirmation by molecular biological analyses. At the transition between the mesophilic and thermophilic range around 40 degrees C-60 degrees C, sulfate-reducing activity appears to be decreased, particularly in more oligotrophic settings, but shows a slight recovery at higher temperatures.
KW  - sulfate reduction
KW  - subsurface life
KW  - deep biosphere
KW  - thermophiles;
KW  - Guaymas Basin
Y1  - 2022
U6  - https://doi.org/10.3389/fmicb.2022.845250
SN  - 1664-302X
VL  - 13
PB  - Frontiers Media
CY  - Lausanne
ER  - 
TY  - JOUR
A1  - Cesar Fernández, Guillermo
A1  - Lecomte, Karina
A1  - Vignoni, Paula
A1  - Soto-Rueda, Eliana Marcela
A1  - Coria, Silvia H.
A1  - Lirio, Juan Manuel
A1  - Mlewski, Estela Cecilia
T1  - Prokaryotic diversity and biogeochemical characteristics of benthic microbial ecosystems from James Ross Archipelago (West Antarctica)
JF  - Polar biology : current research and development in science and technology
N2  - The James Ross archipelago houses numerous lakes and ponds. In this region, a vast diatom and cyanobacterial variety has been reported; however, the prokaryotic diversity in microbial mats from these lakes remains poorly explored. 
Here, a high-throughput sequencing of 16S rRNA gene in microbial mats from Lake Bart-Roja in James Ross Island and lakes Pan Negro and North Pan Negro located in Vega Island was performed. Combined with mineralogical and environmental characteristics, we analyzed the diversity and structure of the microbial communities. Sequences assigned to Archaea were extremely low, while Bacteria domain prevailed with the abundance of Proteobacteria (mostly Betaproteobacteriales) followed by Bacteroidetes, Verrucomicrobia, Firmicutes, and Cyanobacteria. 
Local environmental conditions, such as conductivity and Eh, provided differential microbial assemblages that might have implications in the oligotrophic status of the lakes. Consequently, a clear segregation at the family level was observed. 
In this sense, the assigned diversity was related to taxa recognized as denitrifiers and sulfur oxidizers. Particularly, in Lake Pan Negro sulfur-reducing and methanogenic representatives were also found and positively correlate with alkalinity and water depth. 
Moreover, Deinococcus-Thermus was observed in Lake Bart-Roja, while Melainabacteria (Cyanobacteria)-poorly reported in Antarctic mats-was detected in Lake Pan Negro. Epsilonbacteraeota was exclusively found in this lake, suggesting new potential phylotypes. This study contributes to the understanding of the diversity, composition, and structure of Antarctic benthic microbial ecosystems and provides highly valuable information, which can be used as a proxy to evaluate environmental changes affecting Antarctic microbiota.
KW  - Antarctica
KW  - microbial mats
KW  - microbial diversity
KW  - 16S rRNA genes
KW  - James Ross archipelago
Y1  - 2022
U6  - https://doi.org/10.1007/s00300-021-02997-z
SN  - 0722-4060
SN  - 1432-2056
VL  - 45
IS  - 3
SP  - 405
EP  - 418
PB  - Springer
CY  - Berlin ; Heidelberg
ER  - 
TY  - THES
A1  - Pan, Mengdi
T1  - Systematic studies on the thermodynamic properties of gas hydrates and their formation/dissociation/transformation behaviors
T1  - Systematische Untersuchungen zu den thermodynamischen Eigenschaften von Gashydraten und ihrem Bildungs-/Dissoziations-/Umwandlungsverhalten
N2  - Gas hydrates are ice-like crystalline compounds made of water cavities that retain various types of guest molecules. Natural gas hydrates are CH4-rich but also contain higher hydrocarbons as well as CO2, H2S, etc. They are highly dependent of local pressure and temperature conditions. Considering the high energy content, natural gas hydrates are artificially dissociated for the production of methane gas. Besides, they may also dissociate in response to global warming. It is therefore crucial to investigate the hydrate nucleation and growth process at a molecular level. The understanding of how guest molecules in the hydrate cavities respond to warming climate or gas injection is also of great importance.
This thesis is concerned with a systematic investigation of simple and mixed gas hydrates at conditions relevant to the natural hydrate reservoir in Qilian Mountain permafrost, China. A high-pressure cell that integrated into the confocal Raman spectroscopy ensured a precise and continuous characterization of the hydrate phase during formation/dissociation/transformation processes with a high special and spectral resolution. By applying laboratory experiments, the formation of mixed gas hydrates containing other hydrocarbons besides methane was simulated in consideration of the effects from gas supply conditions and sediments. The results revealed a preferential enclathration of different guest molecules in hydrate cavities and further refute the common hypothesis of the coexistence of hydrate phases due to a changing feed gas phase. However, the presence of specific minerals and organic compounds in sediments may have significant impacts on the coexisting solid phases. With regard to the dissociation, the formation damage caused by fines mobilization and migration during hydrate decomposition was reported for the first time, illustrating the complex interactions between fine grains and hydrate particles. Gas hydrates, starting from simple CH4 hydrates to binary CH4—C3H8 hydrates and multi-component mixed hydrates were decomposed by thermal stimulation mimicking global warming. The mechanisms of guest substitution in hydrate structures were studied through the experimental data obtained from CH4—CO2, CH4—mixed gas hydrates and mixed gas hydrates—CO2 systems. For the first time, a second transformation behavior was documented during the transformation process from CH4 hydrates to CO2-rich mixed hydrates. Most of the crystals grew or maintained when exposed to CO2 gas while some others decreased in sizes and even disappeared over time. The highlight of the two last experimental simulations was to visualize and characterize the hydrate crystals which were at different structural transition stages. These experimental simulations enhanced our knowledge about the mixed gas hydrates in natural reservoirs and improved our capability to assess the response to global warming.
N2  - Gashydrate sind eisähnliche, kristalline Verbindungen bestehend aus Wasserkäfigen, in denen verschiedene Arten von Gastmolekülen eingeschlossen sind. Natürliche Gashydrate sind CH4-reich, enthalten aber auch höhere Kohlenwasserstoffe sowie CO2, H2S usw. Sie sind stark von den lokalen Druck- und Temperaturbedingungen abhängig. Aufgrund ihres hohen Energiegehalts  werden natürliche Gashydrate zur Produktion von Methangas kontrolliert zersetzt. Sie können sich aber auch als Reaktion auf die globale Erwärmung zersetzen. Daher ist es von entscheidender Bedeutung, den Hydratnukleation und des Wachstumsprozesses auf molekularer Ebene zu verstehen. Es ist auch von großer Bedeutung zu klären, wie die Gastmoleküle in den Hydratkäftigen auf die Erderwärmung oder die Gasinjektion antworten.
Diese Arbeit beschäftigt sich mit einer systematischen Untersuchung von einfachen und gemischten Gashydraten unter Bedingungen, die für die natürlichen Hydratvorkommen im Qilian Mountain Permafrost, China, relevant sind. Eine in die konfokale Raman-Spektroskopie integrierte Hochdruckzelle gewährleistet eine präzise und kontinuierliche Charakterisierung der Hydratphase während des Bildungs-/Dissoziations-/Umwandlungsprozesses mit hoher örtlicher und spektraler Auflösung. Anhand von Laborversuchen wurde der Entstehungsprozess von gemischten Gashydraten unter Berücksichtigung der Auswirkungen unterschiedliches Gaszufuhr und Sedimenten simuliert. Die Ergebnisse zeigten eine bevorzugte Einlagerung verschiedener Gastmoleküle in die Hydratkäfige und widerlegen die gängige Hypothese der Bildung koexistierender Hydratphasen aufgrund einer sich ändernden Gasphase. Das Vorhandensein bestimmter Mineralien und organischer Verbindungen in Sedimenten kann ebenfalls erhebliche Auswirkungen auf die koexistierenden festen Phasen haben. Bezüglich der Hydratzersetzung konnte im Rahmen dieser Arbeit erstmals über die Formationsschädigung durch Feinkornmobilisierung und -migration beim Hydratabbau berichtet werden, was die komplexen Wechselwirkungen zwischen feinen Sedimentkörnern und Hydratpartikeln verdeutlicht. Gashydrate, angefangen von einfachen CH4-Hydraten über binäre CH4-C3H8-Hydrate bis hin zu Mehrkomponenten-Mischhydraten, wurden durch thermische Stimulation zersetzt, um die Reaktion auf die globale Erwärmung nachzuahmen. Die Mechanismen der Substitution der Gasmoleküle in Hydratstrukturen wurden anhand der experimentellen Daten von CH4-CO2-, CH4-Mischgashydraten und Mischgashydraten-CO2-Systemen untersucht. Erstmals wurde ein zweites Umwandlungsverhalten während des Umwandlungsprozesses von CH4-Hydraten zu CO2-reichen Mischhydraten dokumentiert. In den meisten Fällen wird das Modell des Schrumpfenden Kerns (Shrinking-core-model) unterstützt, während in einigen anderen Fällen die Kristalle mit konstanter Geschwindigkeit umwandelten. Der Höhepunkt der beiden letzten experimentellen Simulationen war die Visualisierung und Charakterisierung von Hydratkristallen, die sich in verschiedenen strukturellen Übergangsstadien befanden. Diese experimentellen Simulationen erweiterten unser Wissen über gemischte Gashydrate in natürlichen Lagerstätten und verbesserten unsere Fähigkeit, die Reaktion auf die globale Erwärmung zu bewerten.
KW  - gas hydrates
KW  - Raman spectroscopy
KW  - thermodynamic and kinetic properties
KW  - Gashydrate
KW  - Raman-Spektroskopie
KW  - thermodynamische und kinetische Eigenschaften
Y1  - 2022
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-554760
ER  - 
TY  - JOUR
A1  - Ou, Qi
A1  - Daout, Simon
A1  - Weiss, Jonathan R.
A1  - Shen, Lin
A1  - Lazecky, Milan
A1  - Wright, Tim J.
A1  - Parsons, Barry E.
T1  - Large-Scale interseismic strain mapping of the NE Tibetan Plateau from Sentinel-1 Interferometry
JF  - Journal of geophysical research : Solid earth
N2  - The launches of the Sentinel-1 synthetic aperture radar satellites in 2014 and 2016 started a new era of high-resolution velocity and strain rate mapping for the continents. However, multiple challenges exist in tying independently processed velocity data sets to a common reference frame and producing high-resolution strain rate fields. We analyze Sentinel-1 data acquired between 2014 and 2019 over the northeast Tibetan Plateau, and develop new methods to derive east and vertical velocities with similar to 100 m resolution and similar to 1 mm/yr accuracy across an area of 440,000 km(2). By implementing a new method of combining horizontal gradients of filtered east and interpolated north velocities, we derive the first similar to 1 km resolution strain rate field for this tectonically active region. The strain rate fields show concentrated shear strain along the Haiyuan and East Kunlun Faults, and local contractional strain on fault junctions, within the Qilianshan thrusts, and around the Longyangxia Reservoir. The Laohushan-Jingtai creeping section of the Haiyuan Fault is highlighted in our data set by extremely rapid strain rates. Strain across unknown portions of the Haiyuan Fault system, including shear on the eastern extension of the Dabanshan Fault and contraction at the western flank of the Quwushan, highlight unmapped tectonic structures. In addition to the uplift across most of the lowlands, the vertical velocities also contain climatic, hydrological or anthropogenic-related deformation signals. We demonstrate the enhanced view of large-scale active tectonic processes provided by high-resolution velocities and strain rates derived from Sentinel-1 data and highlight associated wide-ranging research applications.
KW  - Sentinel-1 InSAR
KW  - interseismic strain rate
KW  - creep and unmapped faults;
KW  - hydrological uplift and subsidence
KW  - tectonic geodesy
KW  - surface velocity
KW  - mapping
Y1  - 2022
U6  - https://doi.org/10.1029/2022JB024176
SN  - 2169-9313
SN  - 2169-9356
VL  - 127
IS  - 6
PB  - American Geophysical Union
CY  - Washington
ER  - 
TY  - JOUR
A1  - Nguyen, Tam
A1  - Kumar, Rohini
A1  - Musolff, Andreas
A1  - Lutz, Stefanie R.
A1  - Sarrazin, Fanny
A1  - Attinger, Sabine
A1  - Fleckenstein, Jan H.
T1  - Disparate Seasonal Nitrate Export From Nested Heterogeneous Subcatchments Revealed With StorAge Selection Functions
JF  - Water resources research
N2  - Understanding catchment controls on catchment solute export is a prerequisite for water quality management. StorAge Selection (SAS) functions encapsulate essential information about catchment functioning in terms of discharge selection preference and solute export dynamics. However, they lack information on the spatial origin of solutes when applied at the catchment scale, thereby limiting our understanding of the internal (subcatchment) functioning. Here, we parameterized SAS functions in a spatially explicit way to understand the internal catchment responses and transport dynamics of reactive dissolved nitrate (N-NO3). The model was applied in a nested mesoscale catchment (457 km(2)), consisting of a mountainous partly forested, partly agricultural subcatchment, a middle-reach forested subcatchment, and a lowland agricultural subcatchment. The model captured flow and nitrate concentration dynamics not only at the catchment outlet but also at internal gauging stations. Results reveal disparate subsurface mixing dynamics and nitrate export among headwater and lowland subcatchments. The headwater subcatchment has high seasonal variation in subsurface mixing schemes and younger water in discharge, while the lowland subcatchment has less pronounced seasonality in subsurface mixing and much older water in discharge. Consequently, nitrate concentration in discharge from the headwater subcatchment shows strong seasonality, whereas that from the lowland subcatchment is stable in time. The temporally varying responses of headwater and lowland subcatchments alternate the dominant contribution to nitrate export in high and low-flow periods between subcatchments. Overall, our results demonstrate that the spatially explicit SAS modeling provides useful information about internal catchment functioning, helping to develop or evaluate spatial management practices.
KW  - catchment nitrate export
KW  - StorAge Selection function
KW  - travel time distribution
KW  - mesoscale heterogeneous catchment
KW  - subcatchment response
Y1  - 2022
U6  - https://doi.org/10.1029/2021WR030797
SN  - 0043-1397
SN  - 1944-7973
VL  - 58
IS  - 3
PB  - American Geophysical Union
CY  - Washington
ER  - 
TY  - JOUR
A1  - Gosling, William D.
A1  - Scerri, Eleanor
A1  - Kaboth-Bahr, Stefanie
T1  - The climate and vegetation backdrop to hominin evolution in Africa
JF  - Philosophical transactions of the Royal Society of London : B, Biological sciences
N2  - The most profound shift in the African hydroclimate of the last 1 million years occurred around 300 thousand years (ka) ago. 
This change in African hydroclimate is manifest as an east-west change in moisture balance that cannot be fully explained through linkages to high latitude climate systems. 
The east-west shift is, instead, probably driven by a shift in the tropical Walker Circulation related to sea surface temperature change driven by orbital forcing. Comparing records of past vegetation change, and hominin evolution and development, with this breakpoint in the climate system is challenging owing to the paucity of study sites available and uncertainties regarding the dating of records. Notwithstanding these uncertainties we find that, broadly speaking, both vegetation and hominins change around 300 ka. 
The vegetative backdrop suggests that relative abundance of vegetative resources shifted from western to eastern Africa, although resources would have persisted across the continent. 
The climatic and vegetation changes probably provided challenges for hominins and are broadly coincident with the appearance of Homo sapiens (ca 315 ka) and the emergence of Middle Stone Age technology. 
The concomitant changes in climate, vegetation and hominin evolution suggest that these factors are closely intertwined. 
This article is part of the theme issue 'Tropical forests in the deep human past'.
KW  - hominid
KW  - pollen
KW  - El Nino Southern Oscillation
KW  - habitat
KW  - human evolution
KW  - Homo sapiens
Y1  - 2022
U6  - https://doi.org/10.1098/rstb.2020.0483
SN  - 0962-8436
SN  - 1471-2970
VL  - 377
IS  - 1849
PB  - Royal Society
CY  - London
ER  - 
TY  - JOUR
A1  - Platz, Anna
A1  - Weckmann, Ute
A1  - Pek, Josef
A1  - Kovacikova, Svetlana
A1  - Klanica, Radek
A1  - Mair, Johannes
A1  - Aleid, Basel
T1  - 3D imaging of the subsurface electrical resistivity structure in West Bohemia/Upper Palatinate covering mofettes and quaternary volcanic structures by using magnetotellurics
JF  - Tectonophysics : international journal of geotectonics and the geology and physics of the interior of the earth
N2  - The region of West Bohemia and Upper Palatinate belongs to the West Bohemian Massif. The study area is situated at the junction of three different Variscan tectonic units and hosts the ENE-WSW trending Ohre Rift as well as many different fault systems. The entire region is characterized by ongoing magmatic processes in the intra-continental lithospheric mantle expressed by a series of phenomena, including e.g. the occurrence of repeated earthquake swarms and massive degassing of mantle derived CO2 in form of mineral springs and mofettes. Ongoing active tectonics is mainly manifested by Cenozoic volcanism represented by different Quaternary volcanic structures. All these phenomena make the Ohre Rift a unique target area for European intra-continental geo-scientific research. With magnetotelluric (MT) measurements we image the subsurface distribution of the electrical resistivity and map possible fluid pathways. Two-dimensional (2D) inversion results by Munoz et al. (2018) reveal a conductive channel in the vicinity of the earthquake swarm region that extends from the lower crust to the surface forming a pathway for fluids into the region of the mofettes. A second conductive channel is present in the south of their model; however, their 2D inversions allow ambiguous interpretations of this feature. Therefore, we conducted a large 3D MT field experiment extending the study area towards the south. The 3D inversion result matches well with the known geology imaging different fluid/magma reservoirs at crust-mantle depth and mapping possible fluid pathways from the reservoirs to the surface feeding known mofettes and spas. A comparison of 3D and 2D inversion results suggests that the 2D inversion results are considerably characterized by 3D and off-profile structures. In this context, the new results advocate for the swarm earthquakes being located in the resistive host rock surrounding the conductive channels; a finding in line with observations e.g. at the San Andreas Fault, California.
KW  - Magnetotellurics
KW  - Ohre Rift
KW  - Conductive channel
KW  - Fluid/magma reservoir
KW  - Earthquake swarm
Y1  - 2022
U6  - https://doi.org/10.1016/j.tecto.2022.229353
SN  - 0040-1951
SN  - 1879-3266
VL  - 833
PB  - Elsevier
CY  - Amsterdam
ER  - 
TY  - JOUR
A1  - Türker, Elif
A1  - Cotton, Fabrice
A1  - Pilz, Marco
A1  - Weatherill, Graeme
T1  - Analysis of the 2019 Mw 5.8 Silivri earthquake ground motions
BT  - evidence of systematic azimuthal variations associated with directivity effects
JF  - Seismological research letters
N2  - The main Marmara fault (MMF) extends for 150 km through the Sea of Marmara and forms the only portion of the North Anatolian fault zone that has not ruptured in a large event (Mw >7) for the last 250 yr. Accordingly, this portion is potentially a major source contributing to the seismic hazard of the Istanbul region. On 26 September 2019, a sequence of moderate-sized events started along the MMF only 20 km south of Istanbul and were widely felt by the population. The largest three events, 26 September Mw 5.8 (10:59 UTC), 26 September 2019 Mw 4.1 (11:26 UTC), and 20 January 2020 Mw 4.7 were recorded by numerous strong-motion seismic stations and the resulting ground motions were compared to the predicted means resulting from a set of the most recent ground-motion prediction equations (GMPEs). The estimated residuals were used to investigate the spatial variation of ground motion across the Marmara region. Our results show a strong azimuthal trend in ground-motion residuals, which might indicate systematically repeating directivity effects toward the eastern Marmara region.
Y1  - 2022
U6  - https://doi.org/10.1785/0220210168
SN  - 0895-0695
SN  - 1938-2057
VL  - 93
IS  - 2A
SP  - 693
EP  - 705
PB  - Seismological Society of America
CY  - Boulder, Colo.
ER  - 
TY  - JOUR
A1  - Fischer, Tomáš
A1  - Hrubcova, Pavla
A1  - Dahm, Torsten
A1  - Woith, Heiko
A1  - Vylita, Tomáš
A1  - Ohrnberger, Matthias
A1  - Vlček, Josef
A1  - Horalek, Josef
A1  - Dedecek, Petr
A1  - Zimmer, Martin
A1  - Lipus, Martin P.
A1  - Pierdominici, Simona
A1  - Kallmeyer, Jens
A1  - Krüger, Frank
A1  - Hannemann, Katrin
A1  - Korn, Michael
A1  - Kaempf, Horst
A1  - Reinsch, Thomas
A1  - Klicpera, Jakub
A1  - Vollmer, Daniel
A1  - Daskalopoulou, Kyriaki
T1  - ICDP drilling of the Eger Rift observatory
BT  - magmatic fluids driving the earthquake swarms and deep biosphere
JF  - Scientific drilling : reports on deep earth sampling and monitoring
N2  - The new in situ geodynamic laboratory established in the framework of the ICDP Eger project aims to develop the most modern, comprehensive, multiparameter laboratory at depth for studying earthquake swarms, crustal fluid flow, mantle-derived CO2 and helium degassing, and processes of the deep biosphere. In order to reach a new level of high-frequency, near-source and multiparameter observation of earthquake swarms and related phenomena, such a laboratory comprises a set of shallow boreholes with high-frequency 3-D seismic arrays as well as modern continuous real-time fluid monitoring at depth and the study of the deep biosphere.

This laboratory is located in the western part of the Eger Rift at the border of the Czech Republic and Germany (in the West Bohemia–Vogtland geodynamic region) and comprises a set of five boreholes around the seismoactive zone. To date, all monitoring boreholes have been drilled. This includes the seismic monitoring boreholes S1, S2 and S3 in the crystalline units north and east of the major Nový Kostel seismogenic zone, borehole F3 in the Hartoušov mofette field and borehole S4 in the newly discovered Bažina maar near Libá. Supplementary borehole P1 is being prepared in the Neualbenreuth maar for paleoclimate and biological research. At each of these sites, a borehole broadband seismometer will be installed, and sites S1, S2 and S3 will also host a 3-D seismic array composed of a vertical geophone chain and surface seismic array. Seismic instrumenting has been completed in the S1 borehole and is in preparation in the remaining four monitoring boreholes. The continuous fluid monitoring site of Hartoušov includes three boreholes, F1, F2 and F3, and a pilot monitoring phase is underway. The laboratory also enables one to analyze microbial activity at CO2 mofettes and maar structures in the context of changes in habitats. The drillings into the maar volcanoes contribute to a better understanding of the Quaternary paleoclimate and volcanic activity.
Y1  - 2022
U6  - https://doi.org/10.5194/sd-31-31-2022
SN  - 1816-8957
SN  - 1816-3459
VL  - 31
SP  - 31
EP  - 49
PB  - Copernicus
CY  - Göttingen
ER  - 
TY  - JOUR
A1  - Spallanzani, Roberta
A1  - Koga, Kenneth T.
A1  - Cichy, Sarah B.
A1  - Wiedenbeck, Michael
A1  - Schmidt, Burkhard C.
A1  - Oelze, Marcus
A1  - Wilke, Max
T1  - Lithium and boron diffusivity and isotopic fractionation in hydrated rhyolitic melts
JF  - Contributions to mineralogy and petrology
N2  - Lithium and boron are trace components of magmas, released during exsolution of a gas phase during volcanic activity. 
In this study, we determine the diffusivity and isotopic fractionation of Li and B in hydrous silicate melts. 
Two glasses were synthesized with the same rhyolitic composition (4.2 wt% water), having different Li and B contents; these were studied in diffusion-couple experiments that were performed using an internally heated pressure vessel, operated at 300 MPa in the temperature range 700-1250 degrees C for durations from 0 s to 24 h. From this we determined activation energies for Li and B diffusion of 57 +/- 4 kJ/mol and 152 +/- 15 kJ/mol with pre-exponential factors of 1.53 x 10(-7) m(2)/s and 3.80 x 10(-8) m(2)/s, respectively.
Lithium isotopic fractionation during diffusion gave beta values between 0.15 and 0.20, whereas B showed no clear isotopic fractionation. 

Our Li diffusivities and isotopic fractionation results differ somewhat from earlier published values, but overall confirm that Li diffusivity increases with water content. Our results on B diffusion show that similarly to Li, B mobility increases in the presence of water. 
By applying the Eyring relation, we confirm that B diffusivity is limited by viscous flow in silicate melts. 

Our results on Li and B diffusion present a new tool for understanding degassing-related processes, offering a potential geospeedometer to measure volcanic ascent rates.
KW  - stable isotopes
KW  - diffusion
KW  - isotopic fractionation
KW  - hydrated silicate
KW  - melts
Y1  - 2022
U6  - https://doi.org/10.1007/s00410-022-01937-2
SN  - 0010-7999
SN  - 1432-0967
VL  - 177
IS  - 8
PB  - Springer
CY  - New York
ER  - 
TY  - JOUR
A1  - Kühn, Daniela
A1  - Hainzl, Sebastian
A1  - Dahm, Torsten
A1  - Richter, Gudrun
A1  - Vera Rodriguez, Ismael
T1  - A review of source models to further the understanding of the seismicity of the Groningen field
JF  - Netherlands journal of geosciences : NJG
N2  - The occurrence of felt earthquakes due to gas production in Groningen has initiated numerous studies and model attempts to understand and quantify induced seismicity in this region. The whole bandwidth of available models spans the range from fully deterministic models to purely empirical and stochastic models. In this article, we summarise the most important model approaches, describing their main achievements and limitations. In addition, we discuss remaining open questions and potential future directions of development.
KW  - deterministic
KW  - empirical
KW  - hybrid
KW  - machine learning
KW  - seismicity model
Y1  - 2022
U6  - https://doi.org/10.1017/njg.2022.7
SN  - 0016-7746
SN  - 1573-9708
VL  - 101
PB  - Cambridge Univ. Press
CY  - Cambridge
ER  - 
TY  - JOUR
A1  - Fischer, Tomas
A1  - Hrubcova, Pavla
A1  - Dahm, Torsten
A1  - Woith, Heiko
A1  - Vylita, Tomas
A1  - Ohrnberger, Matthias
A1  - Vlcek, Josef
A1  - Horalek, Josef
A1  - Dedecek, Petr
A1  - Zimmer, Martin
A1  - Lipus, Martin P.
A1  - Pierdominici, Simona
A1  - Kallmeyer, Jens
A1  - Krüger, Frank
A1  - Hannemann, Katrin
A1  - Korn, Michael
A1  - Kämpf, Horst
A1  - Reinsch, Thomas
A1  - Klicpera, Jakub
A1  - Vollmer, Daniel
A1  - Daskalopoulou, Kyriaki
T1  - ICDP drilling of the Eger Rift observatory
BT  - magmatic fluids driving the earthquake swarms and deep biosphere
JF  - Scientific Drilling
N2  - The new in situ geodynamic laboratory established in the framework of the ICDP Eger project aims to develop the most modern, comprehensive, multiparameter laboratory at depth for studying earthquake swarms, crustal fluid flow, mantle-derived CO2 and helium degassing, and processes of the deep biosphere. In order to reach a new level of high-frequency, near-source and multiparameter observation of earthquake swarms and related phenomena, such a laboratory comprises a set of shallow boreholes with high-frequency 3-D seismic arrays as well as modern continuous real-time fluid monitoring at depth and the study of the deep biosphere. 
This laboratory is located in the western part of the Eger Rift at the border of the Czech Republic and Germany (in the West Bohemia-Vogtland geodynamic region) and comprises a set of five boreholes around the seismoactive zone. To date, all monitoring boreholes have been drilled. This includes the seismic monitoring boreholes S1, S2 and S3 in the crystalline units north and east of the major Novy Kostel seismogenic zone, borehole F3 in the Hartousov mofette field and borehole S4 in the newly discovered Bazina maar near Liba. Supplementary borehole P1 is being prepared in the Neualbenreuth maar for paleoclimate and biological research. At each of these sites, a borehole broadband seismometer will be installed, and sites S1, S2 and S3 will also host a 3-D seismic array composed of a vertical geophone chain and surface seismic array. Seismic instrumenting has been completed in the S1 borehole and is in preparation in the remaining four monitoring boreholes. The continuous fluid monitoring site of Hartousov includes three boreholes, F1, F2 and F3, and a pilot monitoring phase is underway. The laboratory also enables one to analyze microbial activity at CO2 mofettes and maar structures in the context of changes in habitats. The drillings into the maar volcanoes contribute to a better understanding of the Quaternary paleoclimate and volcanic activity.
Y1  - 2022
U6  - https://doi.org/10.5194/sd-31-31-2022
SN  - 1816-8957
SN  - 1816-3459
VL  - 31
SP  - 31
EP  - 49
PB  - Copernicus
CY  - Göttingen
ER  - 
TY  - JOUR
A1  - Nievas, Cecilia
A1  - Pilz, Marco
A1  - Prehn, Karsten
A1  - Schorlemmer, Danijel
A1  - Weatherill, Graeme
A1  - Cotton, Fabrice
T1  - Calculating earthquake damage building by building
BT  - the case of the city of Cologne, Germany
JF  - Bulletin of earthquake engineering : official publication of the European Association for Earthquake Engineering
N2  - The creation of building exposure models for seismic risk assessment is frequently challenging due to the lack of availability of detailed information on building structures. Different strategies have been developed in recent years to overcome this, including the use of census data, remote sensing imagery and volunteered graphic information (VGI). This paper presents the development of a building-by-building exposure model based exclusively on openly available datasets, including both VGI and census statistics, which are defined at different levels of spatial resolution and for different moments in time. The initial model stemming purely from building-level data is enriched with statistics aggregated at the neighbourhood and city level by means of a Monte Carlo simulation that enables the generation of full realisations of damage estimates when using the exposure model in the context of an earthquake scenario calculation. Though applicable to any other region of interest where analogous datasets are available, the workflow and approach followed are explained by focusing on the case of the German city of Cologne, for which a scenario earthquake is defined and the potential damage is calculated. The resulting exposure model and damage estimates are presented, and it is shown that the latter are broadly consistent with damage data from the 1978 Albstadt earthquake, notwithstanding the differences in the scenario. Through this real-world application we demonstrate the potential of VGI and open data to be used for exposure modelling for natural risk assessment, when combined with suitable knowledge on building fragility and accounting for the inherent uncertainties.
KW  - Building exposure modelling
KW  - Seismic damage assessment
KW  - Scenario
KW  - earthquake
KW  - Seismic risk
KW  - Cologne
Y1  - 2022
U6  - https://doi.org/10.1007/s10518-021-01303-w
SN  - 1570-761X
SN  - 1573-1456
VL  - 20
IS  - 3
SP  - 1519
EP  - 1565
PB  - Springer
CY  - Dordrecht
ER  - 
TY  - THES
A1  - Niemz, Peter
T1  - Imaging and modeling of hydraulic fractures in crystalline rock via induced seismic activity
T1  - Charakterisierung und Modellierung hydraulischer Brüche in Kristallingestein mit Hilfe induzierter Seismizität
N2  - Enhanced geothermal systems (EGS) are considered a cornerstone of future sustainable energy production. In such systems, high-pressure fluid injections break the rock to provide pathways for water to circulate in and heat up. This approach inherently induces small seismic events that, in rare cases, are felt or can even cause damage. Controlling and reducing the seismic impact of EGS is crucial for a broader public acceptance. To evaluate the applicability of hydraulic fracturing (HF) in EGS and to improve the understanding of fracturing processes and the hydromechanical relation to induced seismicity, six in-situ, meter-scale HF experiments with different injection schemes were performed under controlled conditions in crystalline rock in a depth of 410 m at the Äspö Hard Rock Laboratory (Sweden).

I developed a semi-automated, full-waveform-based detection, classification, and location workflow to extract and characterize the acoustic emission (AE) activity from the continuous recordings of 11 piezoelectric AE sensors. Based on the resulting catalog of 20,000 AEs, with rupture sizes of cm to dm, I mapped and characterized the fracture growth in great detail. The injection using a novel cyclic injection scheme (HF3) had a lower seismic impact than the conventional injections. HF3 induced fewer AEs with a reduced maximum magnitude and significantly larger b-values, implying a decreased number of large events relative to the number of small ones. Furthermore, HF3 showed an increased fracture complexity with multiple fractures or a fracture network. In contrast, the conventional injections developed single, planar fracture zones (Publication 1).

An independent, complementary approach based on a comparison of modeled and observed tilt exploits transient long-period signals recorded at the horizontal components of two broad-band seismometers a few tens of meters apart from the injections. It validated the efficient creation of hydraulic fractures and verified the AE-based fracture geometries. The innovative joint analysis of  AEs and tilt signals revealed different phases of the fracturing process, including the (re-)opening, growth, and aftergrowth of fractures, and provided evidence for the reactivation of a preexisting fault in one of the experiments (Publication 2). A newly developed network-based waveform-similarity analysis applied to the massive AE activity supports the latter finding.

To validate whether the reduction of the seismic impact as observed for the cyclic injection schemes during the Äspö mine-scale experiments is transferable to other scales, I additionally calculated energy budgets for injection experiments from previously conducted laboratory tests and from a field application. Across all three scales, the cyclic injections reduce the seismic impact, as depicted by smaller maximum magnitudes, larger b-values, and decreased injection efficiencies (Publication 3).
N2  - Hydraulisch-stimulierte tiefengeothermale Systeme (Enhanced Geothermal systems, EGS) gelten als einer der Eckpfeiler für die nachhaltige Energieerzeugung der Zukunft. In diesen geothermalen Systemen wird heißes Tiefengestein durch Fluidinjektionen unter hohem Druck aufgebrochen, um Wegsamkeiten zur Erwärmung von Wasser oder anderen Fluiden zu schaffen. Beim Aufbrechen werden zwangsläufig kleine seismische Ereignisse ausgelöst (induzierte Seismizität), die in sehr seltenen Fällen an der Oberfläche spürbar sind, jedoch in extremen Fällen auch Schäden verursachen können. Die Kontrolle bzw. die Reduzierung der seismischen Aktivität in EGS ist daher ein entscheidender Punkt, damit diese Art der Energiegewinnung eine breite gesellschaftliche Akzeptanz findet. 

Grundlage dieser Dissertation ist eine Serie von kontrollierten, hydraulischen Bruchexperimenten mit Bruchdimensionen von einigen Metern. Die Experimente wurden in einer Tiefe von 410 m in kristallinem Gestein eines Versuchsbergwerks (Äspö Hard Rock Laboratory, Schweden) mit unterschiedlichen Injektionsstrategien durchgeführt.  Die detaillierte Auswertung der Bruch-Experimente in dieser Dissertation zielt darauf ab, die Nutzbarkeit von hydraulischen Stimulationen (hydraulic fracturing, HF) in EGS zu untersuchen und das Verständnis von Bruchprozessen sowie der hydromechanischen Beziehung zur induzierten Seismizität zu verbessern.

Um die Schallemissionsaktivität (acoustic emissions, AE), die durch 11 piezoelektrische AE-Sensoren kontinuierlich aufgezeichnet wurde, zu extrahieren und zu charakterisieren, wurde ein halbautomatischer, wellenformbasierter Detektions-, Klassifizierungs- und Lokalisierungsworkflow entwickelt. Mit Hilfe des resultierenden Katalogs von 20000 AEs wurde das Bruchwachstum detailliert kartiert und charakterisiert. Das Experiment mit der neuartigen, zyklischen Injektionsstrategie (HF3) weist einen geringeren seismischen Fußabdruck auf als die Standard-Injektionsstrategie. HF3 induzierte weniger AEs und eine kleinere Maximalmagnitude. Außerdem hatte das Experiment einen signifikant höheren b-Wert, was einer verringerten Anzahl von großen AEs relativ zur Anzahl der kleineren AEs entspricht. Darüber hinaus zeigte HF3 eine erhöhte Komplexität im Bruchmuster mit mehreren Brüchen bzw. einem Netzwerk von Brüchen. Im Gegensatz dazu entwickelten die Standard-Injektionen einzelne, ebene Bruchzonen (Publikation 1).

Zusätzlich zu den induzierten AEs wurden transiente, langperiodische Signale auf den horizontalen Komponenten von zwei Breitband-Seismometern, die wenige Meter von den Brüchen installiert waren, ausgewertet. Diese Signale wurden als Neigungssignale interpretiert und mit modellierten Neigungssignalen verglichen. Der Vergleich zeigt unabhängig, dass hydraulische Brüche geöffnet wurden und bestätigt, dass die AE-basierte Analyse die Bruchgeometrie verlässlich kartieren kann. Die gemeinsame Betrachtung von AEs und Neigungssignalen offenbart verschiedene Phasen des Bruchprozesses: das (wiederholte) Öffnen des Bruches, das Bruchwachstum und das weitere Wachsen des Bruches nach dem Ende der Injektion. Außerdem liefert die Analyse Hinweise auf die Reaktivierung einer natürlichen Bruchzone in einem der Experimente (Publikation 2). Eine neuentwickelte und hier präsentierte Wellenform-Ähnlichkeitsanalyse, die Informationen des gesamten Sensornetzwerkes nutzt und zum ersten Mal auf einen umfangreichen AE-Katalog angewendet wurde, unterstützt diese Interpretation.

Um zu validieren, ob die verringerte Seismizität während der zyklischen Injektion auf der Meter-Skala (Bergwerk) auf andere Maßstäbe übertragbar ist, wurden Energie-Budgets für Injektionsexperimente aus zuvor durchgeführten Laborversuchen und aus einem  Tiefengeothermie-Projekt berechnet. Über alle drei Skalen hinweg zeigen die zyklischen Injektionen einen verringerten seismischen Fußabdruck mit kleineren Maximalmagnituden, größeren b-Werte und einem kleineren Verhältnis von seismisch-abgestrahlter zu injizierter Energie (Publikation 3).
KW  - induced seismicity
KW  - hydraulic fracturing
KW  - enhanced geothermal systems (EGS)
KW  - injection
KW  - deformation
KW  - acoustic emissions
KW  - fracture growth
KW  - injection scheme
KW  - basement rock
KW  - Schallemissionen
KW  - Grundgestein
KW  - Deformation
KW  - verbesserte geothermische Systeme
KW  - Bruchausbreitung
KW  - hydraulisches Aufbrechen
KW  - Induzierte Seismizität
KW  - Injektion
KW  - Injektionsschema
Y1  - 2022
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-556593
ER  - 
TY  - GEN
A1  - Jara Muñoz, Julius
A1  - Melnick, Daniel
A1  - Li, Shaoyang
A1  - Socquet, Anne
A1  - Cortés-Aranda, Joaquín
A1  - Brill, Dominik
A1  - Strecker, Manfred
T1  - The cryptic seismic potential of the Pichilemu blind fault in Chile revealed by off-fault geomorphology
T2  - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe
N2  - The first step towards assessing hazards in seismically active regions involves mapping capable faults and estimating their recurrence times. While the mapping of active faults is commonly based on distinct geologic and geomorphic features evident at the surface, mapping blind seismogenic faults is complicated by the absence of on-fault diagnostic features. Here we investigated the Pichilemu Fault in coastal Chile, unknown until it generated a Mw 7.0 earthquake in 2010. The lack of evident surface faulting suggests activity along a partly-hidden blind fault. We used off-fault deformed marine terraces to estimate a fault-slip rate of 0.52 ± 0.04 m/ka, which, when integrated with satellite geodesy suggests a 2.12 ± 0.2 ka recurrence time for Mw~7.0 normal-faulting earthquakes. We propose that extension in the Pichilemu region is associated with stress changes during megathrust earthquakes and accommodated by sporadic slip during upper-plate earthquakes, which has implications for assessing the seismic potential of cryptic faults along convergent margins and elsewhere.
T3  - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 1294 
Y1  - 2023
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-574616
SN  - 1866-8372
IS  - 1294
ER  - 
TY  - THES
A1  - Esfahani, Reza Dokht Dolatabadi
T1  - Time-dependent monitoring of near-surface and ground motion modelling: developing new data processing approaches based on Music Information Retrieval (MIR) strategies
N2  - Seismology, like many scientific fields, e.g., music information retrieval and speech signal pro- cessing, is experiencing exponential growth in the amount of data acquired by modern seismo- logical networks. In this thesis, I take advantage of the opportunities offered by "big data" and by the methods developed in the areas of music information retrieval and machine learning to predict better the ground motion generated by earthquakes and to study the properties of the surface layers of the Earth. In order to better predict seismic ground motions, I propose two approaches based on unsupervised deep learning methods, an autoencoder network and Generative Adversarial Networks. The autoencoder technique explores a massive amount of ground motion data, evaluates the required parameters, and generates synthetic ground motion data in the Fourier amplitude spectra (FAS) domain. This method is tested on two synthetic datasets and one real dataset. The application on the real dataset shows that the substantial information contained within the FAS data can be encoded to a four to the five-dimensional manifold. Consequently, only a few independent parameters are required for efficient ground motion prediction. I also propose a method based on Conditional Generative Adversarial Networks (CGAN) for simulating ground motion records in the time-frequency and time domains. CGAN generates the time-frequency domains based on the parameters: magnitude, distance, and shear wave velocities to 30 m depth (VS30). After generating the amplitude of the time-frequency domains using the CGAN model, instead of classical conventional methods that assume the amplitude spectra with a random phase spectrum, the phase of the time-frequency domains is recovered by minimizing the observed and reconstructed spectrograms. In the second part of this dissertation, I propose two methods for the monitoring and characterization of near-surface materials and site effect analyses. I implement an autocorrelation function and an interferometry method to monitor the velocity changes of near-surface materials resulting from the Kumamoto earthquake sequence (Japan, 2016). The observed seismic velocity changes during the strong shaking are due to the non-linear response of the near-surface materials. The results show that the velocity changes lasted for about two months after the Kumamoto mainshock. Furthermore, I used the velocity changes to evaluate the in-situ strain-stress relationship. I also propose a method for assessing the site proxy "VS30" using non-invasive analysis. In the proposed method, a dispersion curve of surface waves is inverted to estimate the shear wave velocity of the subsurface. This method is based on the Dix-like linear operators, which relate the shear wave velocity to the phase velocity. The proposed method is fast, efficient, and stable. All of the methods presented in this work can be used for processing "big data" in seismology and for the analysis of weak and strong ground motion data, to predict ground shaking, and to analyze site responses by considering potential time dependencies and nonlinearities.
KW  - ground motion modeling
KW  - machine learning
KW  - near-surface monitoring
KW  - imaging
KW  - generative model
KW  - surface wave
Y1  - 2022
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-567671
ER  - 
TY  - JOUR
A1  - Bannister, Stephen
A1  - Bertrand, Edward A.
A1  - Heimann, Sebastian
A1  - Bourguignon, Sandra
A1  - Asher, Cameron
A1  - Shanks, Jackson
A1  - Harvison, Adrian
T1  - Imaging sub-caldera structure with local seismicity, Okataina Volcanic Centre, Taupo Volcanic Zone, using double-difference seismic tomography
JF  - Journal of volcanology and geothermal research
N2  - We examine sub-caldera structure and seismicity in and around the Okataina Volcanic Centre (OVC), Taupo Volcanic Zone, New Zealand, using seismic data collected over 4+ years with a temporary array of broadband and short-period seismometers, supplementing data from the permanent New Zealand seismometer network. 

We derive a new 3-D image of P-wave seismic velocity for the upper crust in the region, using double-difference seismic tomography and utilising waveform cross-correlations. We subsequently relocate 6989 earthquakes which occurred in the region over the 2010-2021 time period, using the 3D velocity model. 
The seismicity distribution shows spatial clusters west of Lake Rotomahana, as well as beneath Haroharo and the Makatiti Dome, inside the Okataina caldera. Beneath Makatiti Dome 90% of the events are shallower than 7.7 +/- 0.5 km. 

Outside of the Okataina caldera event relocations highlight short (similar to 3-4 km long) streaks of activity in the Ngakuru graben, part of the active Taupo Rift southwest of Okataina caldera. Inside the OVC the relocated seismicity beneath Makatiti appears closely associated with low (similar to 10%) P-wave velocity anomalies, which we resolve in the similar to 5-to-8-km depth range beneath the Okataina caldera, and which are likely related to partial melt and/or fluid-volatile pathways. 
Moment tensor analyses for two larger-magnitude events (M(L)4.5 and M(L)4.9) near Haroharo indicate normal faulting, with NNE-SSW fault strike, but with positive CLVD and positive isotropic components when allowing for a full moment tensor, consistent with a magmatic environment with degassing and/or fluid migration.
KW  - Okataina Caldera
KW  - Taupo Rift
KW  - seismic tomography
KW  - sub-caldera structure
KW  - Volcanic system
Y1  - 2022
U6  - https://doi.org/10.1016/j.jvolgeores.2022.107653
SN  - 0377-0273
SN  - 1872-6097
VL  - 431
PB  - Elsevier
CY  - Amsterdam
ER  - 
TY  - JOUR
A1  - Steirou, Eva
A1  - Gerlitz, Lars
A1  - Sun, Xun
A1  - Apel, Heiko
A1  - Agarwal, Ankit
A1  - Totz, Sonja Juliana
A1  - Merz, Bruno
T1  - Towards seasonal forecasting of flood probabilities in Europe using climate and catchment information
JF  - Scientific reports
N2  - We investigate whether the distribution of maximum seasonal streamflow is significantly affected by catchment or climate state of the season/month ahead. We fit the Generalized Extreme Value (GEV) distribution to extreme seasonal streamflow for around 600 stations across Europe by conditioning the GEV location and scale parameters on 14 indices, which represent the season-ahead climate or catchment state. The comparison of these climate-informed models with the classical GEV distribution, with time-constant parameters, suggests that there is a substantial potential for seasonal forecasting of flood probabilities. The potential varies between seasons and regions. Overall, the season-ahead catchment wetness shows the highest potential, although climate indices based on large-scale atmospheric circulation, sea surface temperature or sea ice concentration also show some skill for certain regions and seasons. Spatially coherent patterns and a substantial fraction of climate-informed models are promising signs towards early alerts to increase flood preparedness already a season ahead.
Y1  - 2022
U6  - https://doi.org/10.1038/s41598-022-16633-1
SN  - 2045-2322
VL  - 12
IS  - 1
PB  - Nature portfolio
CY  - Berlin
ER  - 
TY  - JOUR
A1  - Merz, Bruno
A1  - Basso, Stefano
A1  - Fischer, Svenja
A1  - Lun, David
A1  - Bloeschl, Guenter
A1  - Merz, Ralf
A1  - Guse, Bjorn
A1  - Viglione, Alberto
A1  - Vorogushyn, Sergiy
A1  - Macdonald, Elena
A1  - Wietzke, Luzie
A1  - Schumann, Andreas
T1  - Understanding heavy tails of flood peak distributions
JF  - Water resources research
N2  - Statistical distributions of flood peak discharge often show heavy tail behavior, that is, extreme floods are more likely to occur than would be predicted by commonly used distributions that have exponential asymptotic behavior. 
This heavy tail behavior may surprise flood managers and citizens, as human intuition tends to expect light tail behavior, and the heaviness of the tails is very difficult to predict, which may lead to unnecessarily high flood damage. 
Despite its high importance, the literature on the heavy tail behavior of flood distributions is rather fragmented. 

In this review, we provide a coherent overview of the processes causing heavy flood tails and the implications for science and practice. 
Specifically, we propose nine hypotheses on the mechanisms causing heavy tails in flood peak distributions related to processes in the atmosphere, the catchment, and the river system. 
We then discuss to which extent the current knowledge supports or contradicts these hypotheses. 
We also discuss the statistical conditions for the emergence of heavy tail behavior based on derived distribution theory and relate them to the hypotheses and flood generation mechanisms. 

We review the degree to which the heaviness of the tails can be predicted from process knowledge and data. Finally, we recommend further research toward testing the hypotheses and improving the prediction of heavy tails.
KW  - extreme events
KW  - flood frequency
KW  - flood risk
KW  - upper tail
Y1  - 2022
U6  - https://doi.org/10.1029/2021WR030506
SN  - 0043-1397
SN  - 1944-7973
VL  - 58
IS  - 6
PB  - American Geophysical Union
CY  - Washington
ER  - 
TY  - JOUR
A1  - Macdonald, Elena
A1  - Merz, Bruno
A1  - Guse, Björn
A1  - Wietzke, Luzie
A1  - Ullrich, Sophie
A1  - Kemter, Matthias
A1  - Ahrens, Bodo
A1  - Vorogushyn, Sergiy
T1  - Event and catchment controls of heavy tail behavior of floods
JF  - Water resources research
N2  - In some catchments, the distribution of annual maximum streamflow shows heavy tail behavior, meaning the occurrence probability of extreme events is higher than if the upper tail decayed exponentially. Neglecting heavy tail behavior can lead to an underestimation of the likelihood of extreme floods and the associated risk. Partly contradictory results regarding the controls of heavy tail behavior exist in the literature and the knowledge is still very dispersed and limited. To better understand the drivers, we analyze the upper tail behavior and its controls for 480 catchments in Germany and Austria over a period of more than 50 years. The catchments span from quickly reacting mountain catchments to large lowland catchments, allowing for general conclusions. We compile a wide range of event and catchment characteristics and investigate their association with an indicator of the tail heaviness of flood distributions, namely the shape parameter of the GEV distribution. Following univariate analyses of these characteristics, along with an evaluation of different aggregations of event characteristics, multiple linear regression models, as well as random forests, are constructed. A novel slope indicator, which represents the relation between the return period of flood peaks and event characteristics, captures the controls of heavy tails best. Variables describing the catchment response are found to dominate the heavy tail behavior, followed by event precipitation, flood seasonality, and catchment size. The pre-event moisture state in a catchment has no relevant impact on the tail heaviness even though it does influence flood magnitudes.
KW  - heavy tail behavior
KW  - floods
KW  - event characteristics
KW  - catchment
KW  - characteristics
KW  - catchment response
Y1  - 2022
U6  - https://doi.org/10.1029/2021WR031260
SN  - 0043-1397
SN  - 1944-7973
VL  - 58
IS  - 6
PB  - American Geophysical Union
CY  - Washington
ER  - 
TY  - JOUR
A1  - Farrag, Mostafa
A1  - Brill, Fabio Alexander
A1  - Nguyen, Viet Dung
A1  - Sairam, Nivedita
A1  - Schröter, Kai
A1  - Kreibich, Heidi
A1  - Merz, Bruno
A1  - de Bruijn, Karin M.
A1  - Vorogushyn, Sergiy
T1  - On the role of floodplain storage and hydrodynamic interactions in flood risk estimation
JF  - Hydrological sciences journal = Journal des sciences hydrologiques
N2  - Hydrodynamic interactions, i.e. the floodplain storage effects caused by inundations upstream on flood wave propagation, inundation areas, and flood damage downstream, are important but often ignored in large-scale flood risk assessments. Although new methods considering these effects sometimes emerge, they are often limited to a small or meso scale. In this study, we investigate the role of hydrodynamic interactions and floodplain storage on flood hazard and risk in the German part of the Rhine basin. To do so, we compare a new continuous 1D routing scheme within a flood risk model chain to the piece-wise routing scheme, which largely neglects floodplain storage. The results show that floodplain storage is significant, lowers water levels and discharges, and reduces risks by over 50%. Therefore, for accurate risk assessments, a system approach must be adopted, and floodplain storage and hydrodynamic interactions must carefully be considered.
KW  - hydrodynamic interactions
KW  - derived flood risk analysis
KW  - flood modelling;
KW  - Rhine basin
Y1  - 2022
U6  - https://doi.org/10.1080/02626667.2022.2030058
SN  - 0262-6667
SN  - 2150-3435
VL  - 67
IS  - 4
SP  - 508
EP  - 534
PB  - Routledge, Taylor & Francis Group
CY  - Abingdon
ER  - 
TY  - JOUR
A1  - Eibl, Eva P. S.
A1  - Rosskopf, Martina
A1  - Sciotto, Mariangela
A1  - Currenti, Gilda
A1  - Di Grazia, Giuseppe
A1  - Jousset, Philippe
A1  - Krüger, Frank
A1  - Weber, Michael
T1  - Performance of a rotational sensor to decipher volcano seismic signals on Etna, Italy
JF  - Journal of geophysical research : Solid earth
N2  - Volcano-seismic signals such as long-period events and tremor are important indicators for volcanic activity and unrest. However, their wavefield is complex and characterization and location using traditional seismological instrumentation is often difficult. 
In 2019 we recorded the full seismic wavefield using a newly developed 3C rotational sensor co-located with a 3C traditional seismometer on Etna, Italy. We compare the performance of the rotational sensor, the seismometer and the Istituto Nazionale di Geofisica e Vulcanologia-Osservatorio Etneo (INGV-OE) seismic network with respect to the analysis of complex volcano-seismic signals. We create event catalogs for volcano-tectonic (VT) and long-period (LP) events combining a STA/LTA algorithm and cross-correlations. 
The event detection based on the rotational sensor is as reliable as the seismometer-based detection. The LP events are dominated by SH-type waves. Derived SH phase velocities range from 500 to 1,000 m/s for LP events and 300-400 m/s for volcanic tremor. SH-waves compose the tremor during weak volcanic activity and SH- and SV-waves during sustained strombolian activity. 
We derive back azimuths using (a) horizontal rotational components and (b) vertical rotation rate and transverse acceleration. The estimated back azimuths are consistent with the INGV-OE event location for (a) VT events with an epicentral distance larger than 3 km and some closer events, (b) LP events and tremor in the main crater area. Measuring the full wavefield we can reliably analyze the back azimuths, phase velocities and wavefield composition for VT, LP events and tremor in regions that are difficult to access such as volcanoes.
KW  - Etna
KW  - LP
KW  - monitoring
KW  - rotational sensor
KW  - VLP
KW  - volcanoseismology
KW  - VT events and tremor
Y1  - 2022
U6  - https://doi.org/10.1029/2021JB023617
SN  - 0148-0227
SN  - 2169-9356
VL  - 127
IS  - 6
PB  - Wiley
CY  - Hoboken, NJ
ER  - 
TY  - JOUR
A1  - Lescesen, Igor
A1  - Sraj, Mojca
A1  - Basarin, Biljana
A1  - Pavic, Dragoslav
A1  - Mesaros, Minucer
A1  - Mudelsee, Manfred
T1  - Regional flood frequency analysis of the sava river in south-eastern Europe
JF  - Sustainability
N2  - Regional flood frequency analysis (RFFA) is a powerful method for interrogating hydrological series since it combines observational time series from several sites within a region to estimate risk-relevant statistical parameters with higher accuracy than from single-site series. Since RFFA extreme value estimates depend on the shape of the selected distribution of the data-generating stochastic process, there is need for a suitable goodness-of-distributional-fit measure in order to optimally utilize given data. Here we present a novel, least-squares-based measure to select the optimal fit from a set of five distributions, namely Generalized Extreme Value (GEV), Generalized Logistic, Gumbel, Log-Normal Type III and Log-Pearson Type III. The fit metric is applied to annual maximum discharge series from six hydrological stations along the Sava River in South-eastern Europe, spanning the years 1961 to 2020. Results reveal that (1) the Sava River basin can be assessed as hydrologically homogeneous and (2) the GEV distribution provides typically the best fit. We offer hydrological-meteorological insights into the differences among the six stations. For the period studied, almost all stations exhibit statistically insignificant trends, which renders the conclusions about flood risk as relevant for hydrological sciences and the design of regional flood protection infrastructure.
KW  - discharge time series
KW  - flood risk analysis
KW  - Generalized Extreme Value distribution
KW  - L-moments estimation
KW  - regional flood frequency analysis
KW  - Sava River
Y1  - 2022
U6  - https://doi.org/10.3390/su14159282
SN  - 2071-1050
VL  - 14
IS  - 15
PB  - MDPI
CY  - Basel
ER  - 
TY  - JOUR
A1  - Carvalho, Thayslan
A1  - Brosinsky, Arlena
A1  - Foerster, Saskia
A1  - Teixeira, Adunias
A1  - Medeiros, Pedro Henrique Augusto
T1  - Reservoir sediment characterisation by diffuse reflectance spectroscopy in a semiarid region to support sediment reuse for soil fertilization
JF  - Journal of soils and sediments : protection, risk assessment and remediation
N2  - Purpose:
Soil erosion by water yields sediment to surface reservoirs, reducing their storage capacities, changing their geometry, and degrading water quality. Sediment reuse, i.e., fertilization of agricultural soils with the nutrient-enriched sediment from reservoirs, has been proposed as a recovery strategy. However, the sediment needs to meet certain criteria. In this study, we characterize sediments from the densely dammed semiarid Northeast Brazil by VNIR-SWIR spectroscopy and assess the effect of spectral resolution and spatial scale on the accuracy of N, P, K, C, electrical conductivity, and clay prediction models. 

Methods
Sediment was collected in 10 empty reservoirs, and physical and chemical laboratory analyses as well as spectral measurements were performed. The spectra, initially measured at 1 nm spectral resolution, were resampled to 5 and 10 nm, and samples were analysed for both high and low spectral resolution at three spatial scales, namely (1) reservoir, (2) catchment, and (3) regional scale. 

Results
Partial least square regressions performed from good to very good in the prediction of clay and electrical conductivity from reservoir (<40 km(2)) to regional (82,500 km(2)) scales. Models for C and N performed satisfactorily at the reservoir scale, but degraded to unsatisfactory at the other scales. Models for P and K were more unstable and performed from unsatisfactorily to satisfactorily at all scales. Coarsening spectral resolution by up to 10 nm only slightly degrades the models' performance, indicating the potential of characterizing sediment from spectral data captured at lower resolutions, such as by hyperspectral satellite sensors. 

Conclusion:
By reducing the costly and time-consuming laboratory analyses, the method helps to promote the sediment reuse as a practice of soil and water conservation.
KW  - Sediment characterization
KW  - Spectroscopy
KW  - Sediment reuse
KW  - Surface
KW  - reservoirs
KW  - Semiarid
KW  - Brazil
Y1  - 2022
U6  - https://doi.org/10.1007/s11368-022-03281-1
SN  - 1439-0108
SN  - 1614-7480
VL  - 22
SP  - 2557
EP  - 2577
PB  - Springer
CY  - Heidelberg
ER  - 
TY  - JOUR
A1  - Kaboth-Bahr, Stefanie
A1  - Mudelsee, Manfred
T1  - The multifaceted history of the Walker Circulation during the Plio-Pleistocene
JF  - Quaternary science reviews : the international multidisciplinary research and review journal
N2  - The Walker Circulation (WC) is an east-west trending band of atmospheric circulation cells along the equator and the predominant controller of heat and moisture transport in the tropics. Its variability is closely linked to the sea-surface temperature (SST) changes across the Pacific, the Indian and the Atlantic Oceans and can have pronounced effects on the humidity regimes of the adjacent continents. In recent years, the evolution of the WC during the Plioand Pleistocene epochs has been intensely studied in the context of the effectiveness of the tropics in modulating global climate change (e.g., the intensification of Northern Hemisphere glaciation). However, the onset of the modern WC pattern as well as its global impact during the Plioand Pleistocene is controversially assessed in the literature. For its onset, previous studies have suggested dates ranging between 2.4 and 0.8 million years ago (Myr), while its argued impact ranges from crucially influencing the increase of Northern Hemisphere ice sheet growth by channelling heat and moisture from the tropics into the high latitudes to having no effect on global ice volume changes. In order to achieve a comprehensive understanding of the spatiotemporal evolution of the WC during this time frame, we statistically analysed 30 globally distributed SST records covering the low and high latitudes between 3.5 and 1.5 Myr, encompassing the Late Pliocene to Early Pleistocene. We utilized a statistical change-point regression model to determine significant change points in the SST evolution of the (sub)-tropics and high latitudes that potentially relate to changes in the WC. We find that the WC experienced a multifaceted evolution between the Late Pliocene and the Early Pleistocene with significant transitional steps at-2.7 and-2.1 Ma. Our results suggest after the Late Pliocene, a pre-modern WC set in, which was characterized by a progressively strengthened Pacific Walker Cell alongside a weakened Indian Ocean Walker Cell. This change was potentially triggered by the constriction of the Indonesian seaway, an important transmitter between the Pacific and Indian Ocean. The ensuing mode of the WC intensified until-2.1 Myr, when SST values around the global scale signalled a progressive strengthening of the Indian Walker Cell in phase with the progressive strengthening of the Pacific and Atlantic Cells. Our findings indicate that a shift from a pre-modern to a modern-like WC potentially only occurred during the mid-Pleistocene.
KW  - Walker circulation
KW  - Plio-pleistocene transition
KW  - Early pleistocene;
KW  - Statistical analysis
KW  - Change-point regression model
Y1  - 2022
U6  - https://doi.org/10.1016/j.quascirev.2022.107529
SN  - 0277-3791
SN  - 1873-457X
VL  - 286
PB  - Elsevier
CY  - Oxford
ER  - 
TY  - JOUR
A1  - Yen, Ming-Hsuan
A1  - von Specht, Sebastian
A1  - Lin, Yen-Yu
A1  - Cotton, Fabrice
A1  - Ma, Kuo-Fong
T1  - Within- and between-event variabilities of strong-velocity pulses of moderate earthquakes within dense seismic arrays
JF  - Bulletin of the Seismological Society of America
N2  - Ground motion with strong-velocity pulses can cause significant damage to buildings and structures at certain periods; hence, knowing the period and velocity amplitude of such pulses is critical for earthquake structural engineering. 
However, the physical factors relating the scaling of pulse periods with magnitude are poorly understood. 
In this study, we investigate moderate but damaging earthquakes (M-w 6-7) and characterize ground- motion pulses using the method of Shahi and Baker (2014) while considering the potential static-offset effects. 
We confirm that the within-event variability of the pulses is large. The identified pulses in this study are mostly from strike-slip-like earthquakes. We further perform simulations using the freq uency-wavenumber algorithm to investigate the causes of the variability of the pulse periods within and between events for moderate strike-slip earthquakes. 
We test the effect of fault dips, and the impact of the asperity locations and sizes. The simulations reveal that the asperity properties have a high impact on the pulse periods and amplitudes at nearby stations. 
Our results emphasize the importance of asperity characteristics, in addition to earthquake magnitudes for the occurrence and properties of pulses produced by the forward directivity effect. 
We finally quantify and discuss within- and between-event variabilities of pulse properties at short distances.
Y1  - 2021
U6  - https://doi.org/10.1785/0120200376
SN  - 0037-1106
SN  - 1943-3573
VL  - 112
IS  - 1
SP  - 361
EP  - 380
PB  - Seismological Society of America
CY  - El Cerito, Calif.
ER  - 
TY  - JOUR
A1  - Wolf, Sebastian G.
A1  - Huismans, Ritske S.
A1  - Braun, Jean
A1  - Yuan, Xiaoping
T1  - Topography of mountain belts controlled by rheology and surface processes
JF  - Nature : the international weekly journal of science
N2  - It is widely recognized that collisional mountain belt topography is generated by crustal thickening and lowered by river bedrock erosion, linking climate and tectonics(1-4). However, whether surface processes or lithospheric strength control mountain belt height, shape and longevity remains uncertain. Additionally, how to reconcile high erosion rates in some active orogens with long-term survival of mountain belts for hundreds of millions of years remains enigmatic. Here we investigate mountain belt growth and decay using a new coupled surface process(5,6) and mantle-scale tectonic model(7). End-member models and the new non-dimensional Beaumont number, Bm, quantify how surface processes and tectonics control the topographic evolution of mountain belts, and enable the definition of three end-member types of growing orogens: type 1, non-steady state, strength controlled (Bm > 0.5); type 2, flux steady state(8), strength controlled (Bm approximate to 0.4-0.5); and type 3, flux steady state, erosion controlled (Bm < 0.4). Our results indicate that tectonics dominate in Himalaya-Tibet and the Central Andes (both type 1), efficient surface processes balance high convergence rates in Taiwan (probably type 2) and surface processes dominate in the Southern Alps of New Zealand (type 3). Orogenic decay is determined by erosional efficiency and can be subdivided into two phases with variable isostatic rebound characteristics and associated timescales. The results presented here provide a unified framework explaining how surface processes and lithospheric strength control the height, shape, and longevity of mountain belts.
Y1  - 2022
U6  - https://doi.org/10.1038/s41586-022-04700-6
SN  - 0028-0836
SN  - 1476-4687
VL  - 606
IS  - 7914
SP  - 516
EP  - 521
PB  - Nature portfolio
CY  - Berlin
ER  - 
TY  - JOUR
A1  - Inceoglu, Fadil
A1  - Shprits, Yuri
A1  - Heinemann, Stephan G.
A1  - Bianco, Stefano
T1  - Identification of coronal holes on AIA/SDO images using unsupervised machine learning
JF  - The astrophysical journal : an international review of spectroscopy and astronomical physics
N2  - Through its magnetic activity, the Sun governs the conditions in Earth's vicinity, creating space weather events, which have drastic effects on our space- and ground-based technology. 
One of the most important solar magnetic features creating the space weather is the solar wind that originates from the coronal holes (CHs). 
The identification of the CHs on the Sun as one of the source regions of the solar wind is therefore crucial to achieve predictive capabilities. 

In this study, we used an unsupervised machine-learning method, k-means, to pixel-wise cluster the passband images of the Sun taken by the Atmospheric Imaging Assembly on the Solar Dynamics Observatory in 171, 193, and 211 angstrom in different combinations. 

Our results show that the pixel-wise k-means clustering together with systematic pre- and postprocessing steps provides compatible results with those from complex methods, such as convolutional neural networks. 
More importantly, our study shows that there is a need for a CH database where a consensus about the CH boundaries is reached by observers independently. 
This database then can be used as the "ground truth," when using a supervised method or just to evaluate the goodness of the models.
Y1  - 2022
U6  - https://doi.org/10.3847/1538-4357/ac5f43
SN  - 1538-4357
VL  - 930
IS  - 2
PB  - IOP Publ. Ltd.
CY  - Bristol
ER  - 
TY  - JOUR
A1  - Landis, Daji August
A1  - Saikin, Anthony
A1  - Zhelavskaya, Irina
A1  - Drozdov, Alexander
A1  - Aseev, Nikita
A1  - Shprits, Yuri
A1  - Pfitzer, Maximilian F.
A1  - Smirnov, Artem G.
T1  - NARX Neural Network Derivations of the Outer Boundary Radiation Belt Electron Flux
JF  - Space Weather: the international journal of research and applications
N2  - We present two new empirical models of radiation belt electron flux at geostationary orbit. GOES-15 measurements of 0.8 MeV electrons were used to train a Nonlinear Autoregressive with Exogenous input (NARX) neural network for both modeling GOES-15 flux values and an upper boundary condition scaling factor (BF). The GOES-15 flux model utilizes an input and feedback delay of 2 and 2 time steps (i.e., 5 min time steps) with the most efficient number of hidden layers set to 10. Magnetic local time, Dst, Kp, solar wind dynamic pressure, AE, and solar wind velocity were found to perform as predicative indicators of GOES-15 flux and therefore were used as the exogenous inputs. The NARX-derived upper boundary condition scaling factor was used in conjunction with the Versatile Electron Radiation Belt (VERB) code to produce reconstructions of the radiation belts during the period of July-November 1990, independent of in-situ observations. Here, Kp was chosen as the sole exogenous input to be more compatible with the VERB code. This Combined Release and Radiation Effects Satellite-era reconstruction showcases the potential to use these neural network-derived boundary conditions as a method of hindcasting the historical radiation belts. This study serves as a companion paper to another recently published study on reconstructing the radiation belts during Solar Cycles 17-24 (Saikin et al., 2021, ), for which the results featured in this paper were used.
KW  - radiation belts
KW  - forecasting (1922, 4315, 7924, 7964)
KW  - machine learning (0555)
Y1  - 2022
U6  - https://doi.org/10.1029/2021SW002774
SN  - 1542-7390
VL  - 20
IS  - 5
PB  - American Geophysical Union
CY  - Washington
ER  - 
TY  - JOUR
A1  - Shprits, Yuri
A1  - Allison, Hayley J.
A1  - Wang, Dedong
A1  - Drozdov, Alexander
A1  - Szabo-Roberts, Matyas
A1  - Zhelavskaya, Irina
A1  - Vasile, Ruggero
T1  - A new population of ultra-relativistic electrons in the outer radiation zone
JF  - Journal of geophysical research : Space physics
N2  - Van Allen Probes measurements revealed the presence of the most unusual structures in the ultra-relativistic radiation belts. Detailed modeling, analysis of pitch angle distributions, analysis of the difference between relativistic and ultra-realistic electron evolution, along with theoretical studies of the scattering and wave growth, all indicate that electromagnetic ion cyclotron (EMIC) waves can produce a very efficient loss of the ultra-relativistic electrons in the heart of the radiation belts. Moreover, a detailed analysis of the profiles of phase space densities provides direct evidence for localized loss by EMIC waves. The evolution of multi-MeV fluxes shows dramatic and very sudden enhancements of electrons for selected storms. Analysis of phase space density profiles reveals that growing peaks at different values of the first invariant are formed at approximately the same radial distance from the Earth and show the sequential formation of the peaks from lower to higher energies, indicating that local energy diffusion is the dominant source of the acceleration from MeV to multi-MeV energies. Further simultaneous analysis of the background density and ultra-relativistic electron fluxes shows that the acceleration to multi-MeV energies only occurs when plasma density is significantly depleted outside of the plasmasphere, which is consistent with the modeling of acceleration due to chorus waves.
KW  - radiation belts
KW  - ultra-relativistic electrons
KW  - EMIC waves
KW  - modeling;
KW  - plasma density
KW  - chorus waves
Y1  - 2022
U6  - https://doi.org/10.1029/2021JA030214
SN  - 2169-9380
SN  - 2169-9402
VL  - 127
IS  - 5
PB  - American Geophysical Union
CY  - Washington
ER  - 
TY  - JOUR
A1  - Drozdov, Alexander
A1  - Allison, Hayley J.
A1  - Shprits, Yuri
A1  - Usanova, Maria E.
A1  - Saikin, Anthony
A1  - Wang, Dedong
T1  - Depletions of Multi-MeV Electrons and their association to Minima in Phase Space Density
JF  - Geophysical research letters
N2  - Fast-localized electron loss, resulting from interactions with electromagnetic ion cyclotron (EMIC) waves, can produce deepening minima in phase space density (PSD) radial profiles. Here, we perform a statistical analysis of local PSD minima to quantify how readily these are associated with radiation belt depletions. The statistics of PSD minima observed over a year are compared to the Versatile Electron Radiation Belts (VERB) simulations, both including and excluding EMIC waves. The observed minima distribution can only be achieved in the simulation including EMIC waves, indicating their importance in the dynamics of the radiation belts. By analyzing electron flux depletions in conjunction with the observed PSD minima, we show that, in the heart of the outer radiation belt (L* < 5), on average, 53% of multi-MeV electron depletions are associated with PSD minima, demonstrating that fast localized loss by interactions with EMIC waves are a common and crucial process for ultra-relativistic electron populations.
KW  - radiation belts
KW  - EMIC
KW  - VERB
KW  - PSD
Y1  - 2022
U6  - https://doi.org/10.1029/2021GL097620
SN  - 0094-8276
SN  - 1944-8007
VL  - 49
IS  - 8
PB  - American Geophysical Union
CY  - Washington
ER  - 
TY  - GEN
A1  - Schmidt, Lena Katharina
A1  - Francke, Till
A1  - Rottler, Erwin
A1  - Blume, Theresa
A1  - Schöber, Johannes
T1  - Suspended sediment and discharge dynamics in a glaciated alpine environment: identifying crucial areas and time periods on several spatial and temporal scales in the Ötztal, Austria
T2  - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe
N2  - Glaciated high-alpine areas are fundamentally altered by climate change, with well-known implications for hydrology, e.g., due to glacier retreat, longer snow-free periods, and more frequent and intense summer rainstorms. While knowledge on how these hydrological changes will propagate to suspended sediment dynamics is still scarce, it is needed to inform mitigation and adaptation strategies. To understand the processes and source areas most relevant to sediment dynamics, we analyzed discharge and sediment dynamics in high temporal resolution as well as their patterns on several spatial scales, which to date few studies have done.

We used a nested catchment setup in the Upper Ötztal in Tyrol, Austria, where high-resolution (15 min) time series of discharge and suspended sediment concentrations are available for up to 15 years (2006–2020). The catchments of the gauges in Vent, Sölden and Tumpen range from 100 to almost 800 km2 with 10 % to 30 % glacier cover and span an elevation range of 930 to 3772 m a.s.l. We analyzed discharge and suspended sediment yields (SSY), their distribution in space, their seasonality and spatial differences therein, and the relative importance of short-term events. We complemented our analysis by linking the observations to satellite-based snow cover maps, glacier inventories, mass balances and precipitation data.

Our results indicate that the areas above 2500 m a.s.l., characterized by glacier tongues and the most recently deglaciated areas, are crucial for sediment generation in all sub-catchments. This notion is supported by the synchronous spring onset of sediment export at the three gauges, which coincides with snowmelt above 2500 m but lags behind spring discharge onsets. This points at a limitation of suspended sediment supply as long as the areas above 2500 m are snow-covered. The positive correlation of annual SSY with glacier cover (among catchments) and glacier mass balances (within a catchment) further supports the importance of the glacier-dominated areas. The analysis of short-term events showed that summer precipitation events were associated with peak sediment concentrations and yields but on average accounted for only 21 % of the annual SSY in the headwaters. These results indicate that under current conditions, thermally induced sediment export (through snow and glacier melt) is dominant in the study area.

Our results extend the scientific knowledge on current hydro-sedimentological conditions in glaciated high-alpine areas and provide a baseline for studies on projected future changes in hydro-sedimentological system dynamics.
T3  - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 1296 
Y1  - 2023
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-576564
SN  - 1866-8372
IS  - 1296
SP  - 653
EP  - 669
ER  - 
TY  - JOUR
A1  - Li, Wenjia
A1  - Tian, Fang
A1  - Rudaya, Natalya A.
A1  - Herzschuh, Ulrike
A1  - Cao, Xianyong
T1  - Pollen-based holocene thawing-history of permafrost in Northern Asia and its potential impacts on climate change
JF  - Frontiers in Ecology and Evolution
N2  - As the recent permafrost thawing of northern Asia proceeds due to anthropogenic climate change, precise and detailed palaeoecological records from past warm periods are essential to anticipate the extent of future permafrost variations. Here, based on the modern relationship between permafrost and vegetation (represented by pollen assemblages), we trained a Random Forest model using pollen and permafrost data and verified its reliability to reconstruct the history of permafrost in northern Asia during the Holocene. An early Holocene (12-8 cal ka BP) strong thawing trend, a middle-to-late Holocene (8-2 cal ka BP) relatively slow thawing trend, and a late Holocene freezing trend of permafrost in northern Asia are consistent with climatic proxies such as summer solar radiation and Northern Hemisphere temperature. The extensive distribution of permafrost in northern Asia inhibited the spread of evergreen coniferous trees during the early Holocene warming and might have decelerated the enhancement of the East Asian summer monsoon (EASM) by altering hydrological processes and albedo. Based on these findings, we suggest that studies of the EASM should consider more the state of permafrost and vegetation in northern Asia, which are often overlooked and may have a profound impact on climate change in this region.
KW  - pollen
KW  - Random Forest
KW  - Siberia
KW  - East Asian summer monsoon
KW  - permafrost
Y1  - 2022
U6  - https://doi.org/10.3389/fevo.2022.894471
SN  - 2296-701X
VL  - 10
PB  - Frontiers Media
CY  - Lausanne
ER  - 
TY  - JOUR
A1  - Zhang, Di
A1  - Cao, Kai
A1  - Yuan, Xiaoping
A1  - Wang, Guocan
A1  - van der Beek, Pieter A.
T1  - Late Oligocene-early Miocene origin of the First Bend of the Yangtze River explained by thrusting-induced river reorganization
JF  - Geomorphology
N2  - The origin of the First Bend of the Yangtze River is key to understanding the birth of the modern Yangtze River. Despite considerable efforts, the timing and mechanism of formation of the First Bend remain highly debated. Inverse river-profile modeling of three tributaries (Chongjiang, Lima, and Gudu) of the Jinsha River, integrated with regional tectonic and geomorphic interpretations, allows the onset of incision at the First Bend to be constrained to 28-20 Ma. The spatio-temporal coincidence of initial river incision and activity of Yulong Thrust Belt in southeastern Tibet highlights thrusting to be fundamental in reshaping the pre-existing stream network at the First Bend. These results enable us to reinterpret a change in sedimentary environment from a braided river to a swamp-like lake in the Jianchuan Basin south of the First Bend, recording the destruction of the hypothesized southwards-flowing paleo-Jinsha and Shuiluo Rivers at ~36-35 Ma by magmatism. During the late Oligoceneearly Miocene, the paleo-Shuiluo River was diverted to the north by focused rock uplift due to thrusting along the Yulong Thrust Belt, which also led to exhumation of the Jianchuan Basin. Diversion of the paleo-Shuiluo River can be explained by capture from a downstream river in the footwall of the Yulong Thrust Belt. Subsequent rapid headward erosion, that was caused by thrusting-induced drop of local base level, is recorded by upstream younging ages for the onset of incision and led to the formation of the First Bend. The combination of new ages for the onset of incision at 28-20 Ma at the First Bend and younger ages upstream indicates northwards expansion of the Jinsha River at a rate of 62 +/- 18 mm/yr. Our results suggest that the origin of the First Bend was likely triggered by thrusting at 28-20 Ma, after which the Yangtze River formed.
KW  - Tibetan Plateau
KW  - Yangtze River
KW  - river incision
KW  - inverse modeling
Y1  - 2022
U6  - https://doi.org/10.1016/j.geomorph.2022.108303
SN  - 0169-555X
SN  - 1872-695X
VL  - 411
PB  - Elsevier Science
CY  - Amsterdam [u.a.]
ER  - 
TY  - JOUR
A1  - Ariagno, Coline
A1  - Le Bouteiller, Caroline
A1  - van der Beek, Pieter A.
A1  - Klotz, Sébastien
T1  - Sediment export in marly badland catchments modulated by frost-cracking intensity, Draix–Bléone Critical Zone Observatory, SE France
JF  - Earth surface dynamics : ESURF ; an interactive open access journal of the European Geosciences Union
N2  - At the interface between the lithosphere and the atmosphere, the critical zone records the complex interactions between erosion, climate, geologic substrate, and life and can be directly monitored. Long data records (30 consecutive years for sediment yields) collected in the sparsely vegetated, steep, and small marly badland catchments of the Draix-Bleone Critical Zone Observatory (CZO), SE France, allow analyzing potential climatic controls on regolith dynamics and sediment export. Although widely accepted as a first-order control, rainfall variability does not fully explain the observed interannual variability in sediment export. Previous studies in this area have suggested that frost-weathering processes could drive regolith production and potentially modulate the observed pattern of sediment export. Here, we define sediment export anomalies as the residuals from a predictive model with annual rainfall intensity above a threshold as the control. We then use continuous soil temperature data recorded at different locations over multiple years to highlight the role of different frost-weathering processes (i.e., ice segregation versus volumetric expansion) in regolith production. Several proxies for different frost-weathering processes have been calculated from these data and compared to the sediment export anomalies, with careful consideration of field data quality. Our results suggest that frost-cracking intensity (linked to ice segregation) can explain about half (47 %-64 %) of the sediment export anomalies. In contrast, the number of freeze-thaw cycles (linked to volumetric expansion) has only a minor impact on catchment sediment response. The time spent below 0 degrees C also correlates well with the sediment export anomalies and requires fewer field data to be calculated than the frost-cracking intensity. Thus, frost-weathering processes modulate sediment export by controlling regolith production in these catchments and should be taken into account when building predictive models of sediment export from these badlands under a changing climate.
Y1  - 2022
U6  - https://doi.org/10.5194/esurf-10-81-2022
SN  - 2196-6311
SN  - 2196-632X
VL  - 10
IS  - 1
SP  - 81
EP  - 96
PB  - Copernicus
CY  - Göttingen
ER  - 
TY  - JOUR
A1  - Fuchs, Matthias
A1  - Palmtag, Juri
A1  - Juhls, Bennet
A1  - Overduin, Pier Paul
A1  - Grosse, Guido
A1  - Abdelwahab, Ahmed
A1  - Bedington, Michael
A1  - Sanders, Tina
A1  - Ogneva, Olga
A1  - Fedorova, Irina
A1  - Zimov, Nikita S.
A1  - Mann, Paul J.
A1  - Strauss, Jens
T1  - High-resolution bathymetry models for the Lena Delta and Kolyma Gulf coastal zones
JF  - Earth system science data
N2  - Arctic river deltas and deltaic near-shore zones represent important land-ocean transition zones influencing sediment dynamics and nutrient fluxes from permafrost-affected terrestrial ecosystems into the coastal Arctic Ocean. To accurately model fluvial carbon and freshwater export from rapidly changing river catchments as well as assess impacts of future change on the Arctic shelf and coastal ecosystems, we need to understand the sea floor characteristics and topographic variety of the coastal zones. To date, digital bathymetrical data from the poorly accessible, shallow, and large areas of the eastern Siberian Arctic shelves are sparse. We have digitized bathymetrical information for nearly 75 000 locations from large-scale (1 V 25000-1 V 500000) current and historical nautical maps of the Lena Delta and the Kolyma Gulf region in northeastern Siberia. We present the first detailed and seamless digital models of coastal zone bathymetry for both delta and gulf regions in 50 and 200m spatial resolution. We validated the resulting bathymetry layers using a combination of our own water depth measurements and a collection of available depth measurements, which showed a strong correlation (r>0.9). Our bathymetrical models will serve as an input for a high-resolution coupled hydrodynamic-ecosystem model to better quantify fluvial and coastal carbon fluxes to the Arctic Ocean, but they may be useful for a range of other studies related to Arctic delta and near-shore dynamics such as modeling of submarine permafrost, near-shore sea ice, or shelf sediment transport. The new digital high-resolution bathymetry products are available on the PANGAEA data set repository for the Lena Delta (https://doi.org/10.1594/PANGAEA.934045; Fuchs et al., 2021a) and Kolyma Gulf region (https://doi.org/10.1594/PANGAEA.934049; Fuchs et al., 2021b), respectively. Likewise, the depth validation data are available on PANGAEA as well (https://doi.org/10.1594/PANGAEA.933187; Fuchs et al., 2021c).
Y1  - 2022
U6  - https://doi.org/10.5194/essd-14-2279-2022
SN  - 1866-3508
SN  - 1866-3516
VL  - 14
IS  - 5
SP  - 2279
EP  - 2301
PB  - Copernicus
CY  - Göttingen
ER  - 
TY  - JOUR
A1  - Mitzscherling, Julia
A1  - MacLean, Joana
A1  - Lipus, Daniel
A1  - Bartholomäus, Alexander
A1  - Mangelsdorf, Kai
A1  - Lipski, André
A1  - Roddatis, Vladimir
A1  - Liebner, Susanne
A1  - Wagner, Dirk
T1  - Nocardioides alcanivorans sp. nov., a novel hexadecane-degrading species isolated from plastic waste
JF  - International journal of systematic and evolutionary microbiology
N2  - Strain NGK65(T), a novel hexadecane degrading, non-motile, Gram-positive, rod-to-coccus shaped, aerobic bacterium, was isolated from plastic polluted soil sampled at a landfill. 
Strain NGK65(T) hydrolysed casein, gelatin, urea and was catalase-positive. It optimally grew at 28 degrees C. in 0-1% NaCl and at pH 7.5-8.0. Glycerol, D-glucose, arbutin, aesculin, salicin, potassium 5-ketogluconate. sucrose, acetate, pyruvate and hexadecane were used as sole carbon sources. 
The predominant membrane fatty acids were iso-C-16:0 followed by iso-C(17:)0 and C-18:1 omega 9c. The major polar lipids were phosphatidylglycerol, phosphatidylethanolamine, phosphatidylinositol and hydroxyphosphatidylinositol. 
The cell-wall peptidoglycan type was A3 gamma, with LL-diaminopimelic acid and glycine as the diagnostic amino acids. MK 8 (H-4) was the predominant menaquinone. Phylogenetic analysis based on 16S rRNA gene sequences indicated that strain NGK65(T) belongs to the genus Nocardioides (phylum Actinobacteria). appearing most closely related to Nocardioides daejeonensis MJ31(T) (98.6%) and Nocardioides dubius KSL-104(T) (98.3%). 
The genomic DNA G+C content of strain NGK65(T) was 68.2%. 
Strain NGK65(T) and the type strains of species involved in the analysis had average nucleotide identity values of 78.3-71.9% as well as digital DNA-DNA hybridization values between 22.5 and 19.7%, which clearly indicated that the isolate represents a novel species within the genus Nocardioides. 
Based on phenotypic and molecular characterization, strain NGK65(T) can clearly be differentiated from its phylogenetic neighbours to establish a novel species, for which the name Nocardioides alcanivorans sp. nov. is proposed. 
The type strain is NGK65(T) (=DSM 113112(T)=NCCB 100846(T)).
KW  - Nocardioides alcanivorans
KW  - hexadecane
KW  - plastic degradation
KW  - terrestrial
KW  - plastisphere
KW  - bacteria
Y1  - 2022
U6  - https://doi.org/10.1099/ijsem.0.005319
SN  - 1466-5026
SN  - 1466-5034
VL  - 72
IS  - 4
PB  - Microbiology Society
CY  - London
ER  - 
TY  - JOUR
A1  - Smith, Taylor
A1  - Traxl, Dominik
A1  - Boers, Niklas
T1  - Empirical evidence for recent global shifts in vegetation resilience
JF  - Nature climate change
N2  - The authors demonstrate that a vegetation system's ability to recover from disturbances-its resilience-can be estimated from its natural variability. Global patterns of resilience loss and gains since the early 1990s reveal shifts towards widespread resilience loss since the early 2000s. 
The character and health of ecosystems worldwide is tightly coupled to changes in Earth's climate. Theory suggests that ecosystem resilience-the ability of ecosystems to resist and recover from external shocks such as droughts and fires-can be inferred from their natural variability. Here, we quantify vegetation resilience globally with complementary metrics based on two independent long-term satellite records. We first empirically confirm that the recovery rates from large perturbations can be closely approximated from internal vegetation variability across vegetation types and climate zones. On the basis of this empirical relationship, we quantify vegetation resilience continuously and globally from 1992 to 2017. Long-term vegetation resilience trends are spatially heterogeneous, with overall increasing resilience in the tropics and decreasing resilience at higher latitudes. Shorter-term trends, however, reveal a marked shift towards a global decline in vegetation resilience since the early 2000s, particularly in the equatorial rainforest belt.
Y1  - 2022
U6  - https://doi.org/10.1038/s41558-022-01352-2
SN  - 1758-678X
SN  - 1758-6798
VL  - 12
IS  - 5
SP  - 477
EP  - 484
PB  - Nature Publ. Group
CY  - London
ER  - 
TY  - JOUR
A1  - Sarr, Anta-Clarisse
A1  - Donnadieu, Yannick
A1  - Bolton, Clara T.
A1  - Ladant, Jean-Baptiste
A1  - Licht, Alexis
A1  - Fluteau, Frédéric
A1  - Laugié, Marie
A1  - Tardif-Becquet, Delphine
A1  - Dupont-Nivet, Guillaume
T1  - Neogene South Asian monsoon rainfall and wind histories diverged due to topographic effects
JF  - Nature geoscience
N2  - The drivers of the evolution of the South Asian Monsoon remain widely debated. An intensification of monsoonal rainfall recorded in terrestrial and marine sediment archives from the earliest Miocene (23-20 million years ago (Ma)) is generally attributed to Himalayan uplift. However, Indian Ocean palaeorecords place the onset of a strong monsoon around 13 Ma, linked to strengthening of the southwesterly winds of the Somali Jet that also force Arabian Sea upwelling. Here we reconcile these divergent records using Earth system model simulations to evaluate the interactions between palaeogeography and ocean-atmosphere dynamics. We show that factors forcing the South Asian Monsoon circulation versus rainfall are decoupled and diachronous. Himalayan and Tibetan Plateau topography predominantly controlled early Miocene rainfall patterns, with limited impact on ocean-atmosphere circulation. The uplift of the East African and Middle Eastern topography played a pivotal role in the establishment of the modern Somali Jet structure above the western Indian Ocean, while strong upwelling initiated as a direct consequence of the emergence of the Arabian Peninsula and the onset of modern-like atmospheric circulation. Our results emphasize that although elevated rainfall seasonality was probably a persistent feature since the India-Asia collision in the Paleogene, modern-like monsoonal atmospheric circulation only emerged in the late Neogene.
Y1  - 2022
U6  - https://doi.org/10.1038/s41561-022-00919-0
SN  - 1752-0894
SN  - 1752-0908
VL  - 15
IS  - 4
SP  - 314
EP  - 319
PB  - Nature Research
CY  - Berlin
ER  - 
TY  - JOUR
A1  - Toumoulin, Agathe
A1  - Tardif-Becquet, Delphine
A1  - Donnadieu, Yannick
A1  - Licht, Alexis
A1  - Ladant, Jean-Baptiste
A1  - Kunzmann, Lutz
A1  - Dupont-Nivet, Guillaume
T1  - Evolution of continental temperature seasonality from the Eocene greenhouse to the Oligocene icehouse
BT  - a model-data comparison
JF  - Climate of the past : an interactive open access journal of the European Geosciences Union
N2  - At the junction of greenhouse and icehouse climate states, the Eocene-Oligocene Transition (EOT) is a key moment in Cenozoic climate history. While it is associated with severe extinctions and biodiversity turnovers on land, the role of terrestrial climate evolution remains poorly resolved, especially the associated changes in seasonality. Some paleobotanical and geochemical continental records in parts of the Northern Hemisphere suggest the EOT is associated with a marked cooling in winter, leading to the development of more pronounced seasons (i.e., an increase in the mean annual range of temperature, MATR). However, the MATR increase has been barely studied by climate models and large uncertainties remain on its origin, geographical extent and impact. In order to better understand and describe temperature seasonality changes between the middle Eocene and the early Oligocene, we use the Earth system model IPSL-CM5A2 and a set of simulations reconstructing the EOT through three major climate forcings: pCO(2) decrease (1120, 840 and 560 ppm), the Antarctic ice-sheet (AIS) formation and the associated sea-level decrease. Our simulations suggest that pCO(2) lowering alone is not sufficient to explain the seasonality evolution described by the data through the EOT but rather that the combined effects of pCO(2) , AIS formation and increased continentality provide the best data-model agreement.pCO(2) decrease induces a zonal pattern with alternating increasing and decreasing seasonality bands particularly strong in the northern high latitudes (up to 8 degrees C MATR increase) due to sea-ice and surface albedo feedback. Conversely, the onset of the AIS is responsible for a more constant surface albedo yearly, which leads to a strong decrease in seasonality in the southern midlatitudes to high latitudes (> 40 degrees S). Finally, continental areas that emerged due to the sea-level lowering cause the largest increase in seasonality and explain most of the global heterogeneity in MATR changes (1MATR) patterns. The Delta MATR patterns we reconstruct are generally consistent with the variability of the EOT biotic crisis intensity across the Northern Hemisphere and provide insights on their underlying mechanisms.
Y1  - 2022
U6  - https://doi.org/10.5194/cp-18-341-2022
SN  - 1814-9324
SN  - 1814-9332
VL  - 18
IS  - 2
SP  - 341
EP  - 362
PB  - Copernicus
CY  - Göttingen
ER  - 
TY  - JOUR
A1  - Haugk, Charlotte
A1  - Jongejans, Loeka L.
A1  - Mangelsdorf, Kai
A1  - Fuchs, Matthias
A1  - Ogneva, Olga
A1  - Palmtag, Juri
A1  - Mollenhauer, Gesine
A1  - Mann, Paul J.
A1  - Overduin, P. Paul
A1  - Grosse, Guido
A1  - Sanders, Tina
A1  - Tuerena, Robyn E.
A1  - Schirrmeister, Lutz
A1  - Wetterich, Sebastian
A1  - Kizyakov, Alexander
A1  - Karger, Cornelia
A1  - Strauss, Jens
T1  - Organic matter characteristics of a rapidly eroding permafrost cliff in NE Siberia (Lena Delta, Laptev Sea region)
JF  - Biogeosciences
N2  - Organic carbon (OC) stored in Arctic permafrost represents one of Earth's largest and most vulnerable terrestrial carbon pools. Amplified climate warming across the Arctic results in widespread permafrost thaw. Permafrost deposits exposed at river cliffs and coasts are particularly susceptible to thawing processes. Accelerating erosion of terrestrial permafrost along shorelines leads to increased transfer of organic matter (OM) to nearshore waters. However, the amount of terrestrial permafrost carbon and nitrogen as well as the OM quality in these deposits is still poorly quantified. We define the OM quality as the intrinsic potential for further transformation, decomposition and mineralisation. Here, we characterise the sources and the quality of OM supplied to the Lena River at a rapidly eroding permafrost river shoreline cliff in the eastern part of the delta (Sobo-Sise Island). Our multi-proxy approach captures bulk elemental, molecu- lar geochemical and carbon isotopic analyses of Late Pleistocene Yedoma permafrost and Holocene cover deposits, discontinuously spanning the last similar to 52 kyr. We showed that the ancient permafrost exposed in the Sobo-Sise cliff has a high organic carbon content (mean of about 5 wt %). The oldest sediments stem from Marine Isotope Stage (MIS) 3 interstadial deposits (dated to 52 to 28 cal ka BP) and are overlaid by last glacial MIS 2 (dated to 28 to 15 cal ka BP) and Holocene MIS 1 (dated to 7-0 cal ka BP) deposits. The relatively high average chain length (ACL) index of n-alkanes along the cliff profile indicates a predominant contribution of vascular plants to the OM composition. The elevated ratio of isoand anteiso-branched fatty acids (FAs) relative to mid- and long-chain (C >= 20) n-FAs in the interstadial MIS 3 and the interglacial MIS 1 deposits suggests stronger microbial activity and consequently higher input of bacterial biomass during these climatically warmer periods. The overall high carbon preference index (CPI) and higher plant fatty acid (HPFA) values as well as high C/N ratios point to a good quality of the preserved OM and thus to a high potential of the OM for decomposition upon thaw. A decrease in HPFA values downwards along the profile probably indicates stronger OM decomposition in the oldest (MIS 3) deposits of the cliff. The characterisation of OM from eroding permafrost leads to a better assessment of the greenhouse gas potential of the OC released into river and nearshore waters in the future.
Y1  - 2022
U6  - https://doi.org/10.5194/bg-19-2079-2022
SN  - 1726-4170
SN  - 1726-4189
VL  - 19
IS  - 7
SP  - 2079
EP  - 2094
PB  - Copernicus
CY  - Göttingen
ER  - 
TY  - JOUR
A1  - Voglimacci-Stephanopoli, Joëlle
A1  - Wendleder, Anna
A1  - Lantuit, Hugues
A1  - Langlois, Alexandre
A1  - Stettner, Samuel
A1  - Schmitt, Andreas
A1  - Dedieu, Jean-Pierre
A1  - Roth, Achim
A1  - Royer, Alain
T1  - Potential of X-band polarimetric synthetic aperture radar co-polar phase difference for arctic snow depth estimation
JF  - Cryosphere
N2  - Changes in snowpack associated with climatic warming has drastic impacts on surface energy balance in the cryosphere. Yet, traditional monitoring techniques, such as punctual measurements in the field, do not cover the full snowpack spatial and temporal variability, which hampers efforts to upscale measurements to the global scale. This variability is one of the primary constraints in model development. In terms of spatial resolution, active microwaves (synthetic aperture radar - SAR) can address the issue and outperform methods based on passive microwaves. Thus, high-spatial-resolution monitoring of snow depth (SD) would allow for better parameterization of local processes that drive the spatial variability of snow. The overall objective of this study is to evaluate the potential of the TerraSAR-X (TSX) SAR sensor and the wave co-polar phase difference (CPD) method for characterizing snow cover at high spatial resolution. Consequently, we first (1) investigate SD and depth hoar fraction (DHF) variability between different vegetation classes in the Ice Creek catchment (Qikiqtaruk/Herschel Island, Yukon, Canada) using in situ measurements collected over the course of a field campaign in 2019; (2) evaluate linkages between snow characteristics and CPD distribution over the 2019 dataset; and (3) determine CPD seasonality considering meteorological data over the 2015-2019 period. SD could be extracted using the CPD when certain conditions are met. A high incidence angle (>30 circle) with a high topographic wetness index (TWI) (>7.0) showed correlation between SD and CPD (R2 up to 0.72). Further, future work should address a threshold of sensitivity to TWI and incidence angle to map snow depth in such environments and assess the potential of using interpolation tools to fill in gaps in SD information on drier vegetation types.
Y1  - 2022
U6  - https://doi.org/10.5194/tc-16-2163-2022
SN  - 1994-0416
SN  - 1994-0424
VL  - 16
IS  - 6
SP  - 2163
EP  - 2181
PB  - Copernicus
CY  - Göttingen
ER  - 
TY  - JOUR
A1  - Kaya, Mustafa Yücel
A1  - Dupont-Nivet, Guillaume
A1  - Frieling, Joost
A1  - Fioroni, Chiara
A1  - Rohrmann, Alexander
A1  - Altıner, Sevinç Özkan
A1  - Vardar, Ezgi
A1  - Tanyas, Hakan
A1  - Mamtimin, Mehmut
A1  - Zhaojie, Guo
T1  - The Eurasian epicontinental sea was an important carbon sink during the Palaeocene-Eocene thermal maximum
JF  - Communications earth and environment
N2  - The Palaeocene-Eocene Thermal Maximum (ca. 56 million years ago) offers a primary analogue for future global warming and carbon cycle recovery. Yet, where and how massive carbon emissions were mitigated during this climate warming event remains largely unknown. Here we show that organic carbon burial in the vast epicontinental seaways that extended over Eurasia provided a major carbon sink during the Palaeocene-Eocene Thermal Maximum. We coupled new and existing stratigraphic analyses to a detailed paleogeographic framework and using spatiotemporal interpolation calculated ca. 720–1300 Gt organic carbon excess burial, focused in the eastern parts of the Eurasian epicontinental seaways. A much larger amount (2160–3900 Gt C, and when accounting for the increase in inundated shelf area 7400–10300 Gt C) could have been sequestered in similar environments globally. With the disappearance of most epicontinental seas since the Oligocene-Miocene, an effective negative carbon cycle feedback also disappeared making the modern carbon cycle critically dependent on the slower silicate weathering feedback.
Y1  - 2022
U6  - https://doi.org/10.1038/s43247-022-00451-4
SN  - 2662-4435
VL  - 3
IS  - 1
PB  - Springer Nature
CY  - London
ER  - 
TY  - JOUR
A1  - Yuan, Xiaoping P.
A1  - Jiao, Ruohong
A1  - Dupont-Nivet, Guillaume
A1  - Shen, Xiaoming
T1  - Southeastern Tibetan Plateau growth revealed by inverse analysis of landscape evolution model
JF  - Geophysical research letters
N2  - The Cenozoic history of the Tibetan Plateau topography is critical for understanding the evolution of the Indian-Eurasian collision, climate, and biodiversity. However, the long-term growth and landscape evolution of the Tibetan Plateau remain ambiguous, it remains unclear if plateau uplift occurred soon after the India-Asia collision in the Paleogene (similar to 50-25 Ma) or later in the Neogene (similar to 20-5 Ma). Here, we reproduce the uplift history of the southeastern Tibetan Plateau using a 2D landscape evolution model, which simultaneously solves fluvial erosion and sediment transport processes in the drainage basins of the Three Rivers region (Yangtze, Mekong, and Salween Rivers). Our model was optimized through a formal inverse analysis with 20,000 forward simulations, which aims to reconcile the transient states of the present-day river profiles. The results, compared to existing paleoelevation and thermochronologic data, suggest initially low elevations (similar to 300-500 m) during the Paleogene, followed by a gradual southeastward propagation of topographic uplift of the plateau margin.
KW  - Tibetan Plateau
KW  - landscape evolution
KW  - fluvial erosion
KW  - inverse analysis
KW  - mountain growth
KW  - propagating uplift
Y1  - 2022
U6  - https://doi.org/10.1029/2021GL097623
SN  - 0094-8276
SN  - 1944-8007
VL  - 49
IS  - 10
PB  - American Geophysical Union
CY  - Washington
ER  - 
TY  - JOUR
A1  - Dahm, Torsten
A1  - Hainzl, Sebastian
T1  - A Coulomb stress response model for time-dependent earthquake forecasts
JF  - Journal of geophysical research : Solid earth
N2  - Seismicity models are probabilistic forecasts of earthquake rates to support seismic hazard assessment. 
Physics-based models allow extrapolating previously unsampled parameter ranges and enable conclusions on underlying tectonic or human-induced processes. 
The Coulomb Failure (CF) and the rate-and-state (RS) models are two widely used physics-based seismicity models both assuming pre-existing populations of faults responding to Coulomb stress changes. 
The CF model depends on the absolute Coulomb stress and assumes instantaneous triggering if stress exceeds a threshold, while the RS model only depends on stress changes. 
Both models can predict background earthquake rates and time-dependent stress effects, but the RS model with its three independent parameters can additionally explain delayed aftershock triggering. 

This study introduces a modified CF model where the instantaneous triggering is replaced by a mean time-to-failure depending on the absolute stress value. 
For the specific choice of an exponential dependence on stress and a stationary initial seismicity rate, we show that the model leads to identical results as the RS model and reproduces the Omori-Utsu relation for aftershock decays as well stress-shadowing effects. 
Thus, both CF and RS models can be seen as special cases of the new model. However, the new stress response model can also account for subcritical initial stress conditions and alternative functions of the mean time-to-failure depending on the problem and fracture mode.
KW  - seismicity
KW  - physics based model
KW  - earthquake physics
Y1  - 2022
U6  - https://doi.org/10.1029/2022JB024443
SN  - 2169-9313
SN  - 2169-9356
VL  - 127
IS  - 9
PB  - American Geophysical Union
CY  - Washington
ER  - 
TY  - JOUR
A1  - Scherbaum, Frank
A1  - Mzhavanadze, Nana
A1  - Rosenzweig, Sebastian
A1  - Müller, Meinard
T1  - Tuning systems of traditional Georgian singing determined from a new corpus of field recordings
JF  - Musicologist
N2  - In this study we examine the tonal organization of the 2016 GVM dataset, a newly-created corpus of high-quality multimedia field recordings of traditional Georgian singing with a focus on Svaneti. For this purpose, we developed a new processing pipeline for the computational analysis of non-western polyphonic music which was subsequently applied to the complete 2016 GVM dataset. 
To evaluate under what conditions a single tuning system is representative of current Svan performance practice, we examined the stability of the obtained tuning systems from an ensemble-, a song-, and a corpus-related perspective. 
Furthermore, we compared the resulting Svan tuning systems with the tuning systems obtained for the Erkomaishvili dataset (Rosenzweig et al., 2020) in the study by Scherbaum et al. (2020). In comparison to a 12-TET (12-tone-equal-temperament) system, the Erkomaishvili and the Svan tuning systems are surprisingly similar. 
Both systems show a strong presence of pure fourths (500 cents) and fifths (700 cents), and 'neutral' thirds (peaking around 350 cents) as well as 'neutral' sixths. 
In addition, the sizes of the melodic and the harmonic seconds in both tuning systems differ systematically from each other, with the size of the harmonic second being systematically larger than the melodic one.
KW  - traditional Georgian music
KW  - tuning
KW  - computational ethnomusicology
Y1  - 2022
U6  - https://doi.org/10.33906/musicologist.1068947
SN  - 2618-5652
VL  - 6
IS  - 2
SP  - 142
EP  - 168
PB  - Trabzon Univ State Conservatory
CY  - Trabzon
ER  - 
TY  - JOUR
A1  - Lück, Erika
A1  - Guillemoteau, Julien
A1  - Tronicke, Jens
A1  - Rummel, Udo
A1  - Hierold, Wilfried
T1  - From point to field scale-indirect monitoring of soil moisture variations at the DWD test site in Falkenberg
JF  - Geoderma : an international journal of soil science
N2  - Information regarding the spatial distribution of soil water content is key in many disciplines and applications including soil and atmospheric sciences, hydrology, and agricultural engineering. 
Thus, within the past decades various experimental methods and strategies have been developed to map spatial variations in soil moisture distribution and to monitor temporal changes. 
Our study examines the combination of electrical resistivity mapping and point observations of soil moisture to infer the spatial and the temporal variability of soil moisture. 
Over a period of around two years, we performed field measurements on six days to collect repeated electrical resistivity mapping data for a nine-hectare test site south-east of Berlin, Germany. 

Permanently installed TDR probes, temporary TDR measurements within permanently installed tubes, and gravimetric measurements using soil samples provided soil moisture data at various selected points. 
In addition, soil analysis and classification results are available for 132 regularly distributed positions up to depths of 1.2 m. 
We compare and link three-dimensional resistivity models obtained via data inversion to soil composition and soil moisture as provided by our point data. 
Both the soil samples and the resistivity models indicate a two-layer medium characterized by a sandy top layer with varying thickness and a loamy bottom soil. 
For all six field campaigns, we observe similar resistivity patterns reflecting the temporally stable influence of soil texture. 

While the overall patterns are stable, the range of resistivity values changes with soil moisture. Finally, to estimate spatial models of soil moisture, we link our soil moisture and resistivity data using empirical petrophysical models relying on a second order polynomial function. 
We observe a mean prediction error for soil moisture of +/-0.034 m3 & BULL; m? 3 using all observation points while we notice that point-specific models further reduce the error. 
Thus, we conclude that our experimental and data analysis strategies represent a reliable approach to establish site-specific models and to estimate three-dimensional moisture distribution including temporal variations.
KW  - earth boundary layer
KW  - electrical conductivity
KW  - electrical resistivity
KW  - near-surface geophysics
KW  - soil moisture at field scale
Y1  - 2022
U6  - https://doi.org/10.1016/j.geoderma.2022.116134
SN  - 0016-7061
SN  - 1872-6259
VL  - 427
PB  - Elsevier
CY  - Amsterdam
ER  - 
TY  - JOUR
A1  - Geng, Rongwei
A1  - Andreev, Andrei
A1  - Kruse, Stefan
A1  - Heim, Birgit
A1  - van Geffen, Femke
A1  - Pestryakova, Luidmila
A1  - Zakharov, Evgenii
A1  - Troeva, Elena I.
A1  - Shevtsova, Iuliia
A1  - Li, Furong
A1  - Zhao, Yan
A1  - Herzschuh, Ulrike
T1  - Modern pollen assemblages from lake sediments and soil in East Siberia and relative pollen productivity estimates for Major Taxa
JF  - Frontiers in Ecology and Evolution
N2  - Modern pollen-vegetation-climate relationships underpin palaeovegetation and palaeoclimate reconstructions from fossil pollen records. East Siberia is an ideal area for investigating the relationships between modern pollen assemblages and near natural vegetation under cold continental climate conditions. Reliable pollen-based quantitative vegetation and climate reconstructions are still scarce due to the limited number of modern pollen datasets. Furthermore, differences in pollen representation of samples from lake sediments and soils are not well understood. Here, we present a new pollen dataset of 48 moss/soil and 24 lake surface-sediment samples collected in Chukotka and central Yakutia in East Siberia. The pollen-vegetation-climate relationships were investigated by ordination analyses. Generally, tundra and taiga vegetation types can be well distinguished in the surface pollen assemblages. Moss/soil and lake samples contain generally similar pollen assemblages as revealed by a Procrustes comparison with some exceptions. Overall, modern pollen assemblages reflect the temperature and precipitation gradients in the study areas as revealed by constrained ordination analysis. We estimate the relative pollen productivity (RPP) of major taxa and the relevant source area of pollen (RSAP) for moss/soil samples from Chukotka and central Yakutia using Extended R-Value (ERV) analysis. The RSAP of the tundra-forest transition area in Chukotka and taiga area in central Yakutia are ca. 1300 and 360 m, respectively. For Chukotka, RPPs relative to both Poaceae and Ericaceae were estimated while RPPs for central Yakutia were relative only to Ericaceae. Relative to Ericaceae (reference taxon, RPP = 1), Larix, Betula, Picea, and Pinus are overrepresented while Alnus, Cyperaceae, Poaceae, and Salix are underrepresented in the pollen spectra. Our estimates are in general agreement with previously published values and provide the basis for reliable quantitative reconstructions of East Siberian vegetation.
KW  - modern pollen assemblages
KW  - pollen-vegetation-climate relationships
KW  - East Siberia
KW  - tundra
KW  - taiga
KW  - relative pollen productivity
KW  - quantitative vegetation reconstruction
Y1  - 2022
U6  - https://doi.org/10.3389/fevo.2022.837857
SN  - 2296-701X
VL  - 10
PB  - Frontiers Media
CY  - Lausanne
ER  - 
TY  - JOUR
A1  - Kumar, Satish
A1  - Guntu, Ravi Kumar
A1  - Agarwal, Ankit
A1  - Villuri, Vasant Govind Kumar
A1  - Pasupuleti, Srinivas
A1  - Kaushal, Deo Raj
A1  - Gosian, Ashwin Kumar
A1  - Bronstert, Axel
T1  - Multi-objective optimization for stormwater management by green-roofs and infiltration trenches to reduce urban flooding in central Delhi
JF  - Journal of hydrology
N2  - Urban surface runoff management via best management practices (BMP) and low impact development (LID) has earned significant recognition owing to positive environmental and ecological impacts. However, due to the complexity of the parameters involved, the estimation of LID efficiency in attenuating the urban surface runoff at the watershed scale is challenging. A planning analysis of employing Green Roofs and Infiltration Trenches as BMPs/LIDs practices for urban surface runoff control is presented in this study. A multi-objective optimization decision-making framework is established by coupling SWMM (Storm Water Management Model) with NSGA-II models to check the performance of BMPs/LIDs concerning the cost-benefit analysis of LID at the watershed scale. Two urbanized areas belonging to Central Delhi in India were used as case studies. The results showed that the SWMM model is useful in simulating optimization problems for managing urban surface runoff. The optimum scenarios efficiently minimized the urban runoff volume while maintaining the BMPs/LIDs implementation costs and size. With BMPs/LIDs implementation, the reduction in runoff volume increases as expenses increase initially; however, there is no noticeable reduction in flood volume after a certain threshold. Contrasted with the haphazard arrangement of BMPs/LIDs, the proposed approach demonstrates 22%-24% runoff reductions for the same expenditures in watershed 1 and 23%-26% in watershed 2. The result of the study provides insights into planning and management of the urban surface runoff control with LID practices. The proposed framework assists the hydrologists in optimum selection and placements of BMPs/LIDs practices to acquire the most extreme ecological advantages with the least expenses.
KW  - Storm water management model
KW  - Genetic algorithm
KW  - NSGA-II
KW  - Best management practice
KW  - Low impact development
KW  - Cost-benefit
Y1  - 2022
U6  - https://doi.org/10.1016/j.jhydrol.2022.127455
SN  - 0022-1694
SN  - 1879-2707
VL  - 606
PB  - Elsevier
CY  - Amsterdam
ER  - 
TY  - JOUR
A1  - Hülscher, Julian
A1  - Sobel, Edward
A1  - Kallnik, Niklas
A1  - Hoffmann, J. Elis
A1  - Millar, Ian L.
A1  - Hartmann, Kai
A1  - Bernhardt, Anne
T1  - Apatites record sedimentary provenance change 4-5 myrs before clay in the Oligocene/Miocene Alpine molasse
JF  - Frontiers in Earth Science
N2  - Extracting information about past tectonic or climatic environmental changes from sedimentary records is a key objective of provenance research. Interpreting the imprint of such changes remains challenging as signals might be altered in the sediment-routing system. 
We investigate the sedimentary provenance of the Oligocene/Miocene Upper Austrian Northern Alpine Foreland Basin and its response to the tectonically driven exhumation of the Tauern Window metamorphic dome (28 +/- 1 Ma) in the Eastern European Alps by using the unprecedented combination of Nd isotopic composition of bulk-rock clay-sized samples and partly previously published multi-proxy (Nd isotopic composition, trace-element geochemistry, U-Pb dating) sand-sized apatite single-grain analysis. 

The basin offers an excellent opportunity to investigate environmental signal propagation into the sedimentary record because comprehensive stratigraphic and seismic datasets can be combined with present research results. The bulk-rock clay-sized fraction epsilon Nd values of well-cutting samples from one well on the northern basin slope remained stable at similar to-9.7 from 27 to 19 Ma but increased after 19 Ma to similar to-9.1. In contrast, apatite single-grain distributions, which were extracted from 22 drill-core samples, changed significantly around 23.3 Ma from apatites dominantly from low-grade (<upper amphibolite-facies) metamorphic sources with Permo-Mesozoic and late Variscan U-Pb ages and epsilon Nd values of -4.4 to dominantly high-grade metamorphic apatites with late Variscan U-Pb ages and epsilon Nd values of -2.2. 

The change in apatite single-grain distributions at 23.3 Ma is interpreted to result from the exposure of a new Upper Austroalpine source nappe with less negative epsilon Nd values triggered by the ongoing Tauern Window exhumation. Combining these data with the clay-sized bulk-rock epsilon Nd values reveals that the provenance changed 4-5 Myrs later at 19 Ma in the clay-sized fraction. 
Reasons for the delayed provenance-change recording are rooted in the characteristics of the applied methods. 
Whereas single-grain distributions of orogen-wide sediment-routing systems can be dominated by geographically small areas with high erosion and mineral fertility rates, bulk-rock methods integrate over the entire drainage basin, thus diminishing extreme values. Hence, by combining these two methods, spatial information are uncovered, enabling a previously unattained understanding of the underlying environmental change.
KW  - apatite geochemistry and U-Pb dating
KW  - Nd isotopic composition
KW  - clay
KW  - provenance
KW  - Northern Alpine Foreland Basin
KW  - Eastern Alps
KW  - Tauern Window;
KW  - sediment routing system
Y1  - 2022
U6  - https://doi.org/10.3389/feart.2022.914409
SN  - 2296-6463
VL  - 10
PB  - Frontiers Media
CY  - Lausanne
ER  - 
TY  - JOUR
A1  - Weidle, Christian
A1  - Wiesenberg, Lars
A1  - El-Sharkawy, Amr
A1  - Krüger, Frank
A1  - Scharf, Andreas
A1  - Agard, Philippe
A1  - Meier, Thomas
T1  - A 3-D crustal shear wave velocity model and Moho map below the Semail Ophiolite, eastern Arabia
JF  - Geophysical journal international
N2  - The Semail Ophiolite in eastern Arabia is the largest and best-exposed slice of oceanic lithosphere on land. Detailed knowledge of the tectonic evolution of the shallow crust, in particular during and after ophiolite obduction in Late Cretaceous times is contrasted by few constraints on physical and compositional properties of the middle and lower continental crust below the obducted units. The role of inherited, pre-obduction crustal architecture remains therefore unaccounted for in our understanding of crustal evolution and the present-day geology. Based on seismological data acquired during a 27-month campaign in northern Oman, Ambient Seismic Noise Tomography and Receiver Function analysis provide for the first time a 3-D radially anisotropic shear wave velocity (V-S) model and a consistent Moho map below the iconic Semail Ophiolite. The model highlights deep crustal boundaries that segment the eastern Arabian basement in two distinct units. The previously undescribed Western Jabal Akhdar Zone separates Arabian crust with typical continental properties and a thickness of similar to 40-45 km in the northwest from a compositionally different terrane in the southeast that is interpreted as a terrane accreted during the Pan-African orogeny in Neoproterozoic times. East of the Ibra Zone, another deep crustal boundary, crustal thickness decreases to 30-35 km and very high lower crustal V-S suggest large-scale mafic intrusions into, and possible underplating of the Arabian continental crust that occurred most likely during Permian breakup of Pangea. Mafic reworking is sharply bounded by the (upper crustal) Semail Gap Fault Zone, northwest of which no such high velocities are found in the crust. Topography of the Oman Mountains is supported by a mild crustal root and Moho depth below the highest topography, the Jabal Akhdar Dome, is similar to 42 km. Radial anisotropy is robustly resolved in the upper crust and aids in discriminating dipping allochthonous units from autochthonous sedimentary rocks that are indistinguishable by isotropic V-S alone. Lateral thickness variations of the ophiolite highlight the Haylayn Ophiolite Massif on the northern flank of Jabal Akhdar Dome and the Hawasina Window as the deepest reaching unit. Ophiolite thickness is similar to 10 km in the southern and northern massifs, and <= 5 km elsewhere.
KW  - Composition and structure of the continental crust
KW  - Asia
KW  - Body waves
KW  - Seismic anisotropy
KW  - Seismic tomography
KW  - Surface waves and free oscillations
Y1  - 2022
U6  - https://doi.org/10.1093/gji/ggac223
SN  - 0956-540X
SN  - 1365-246X
VL  - 231
IS  - 2
SP  - 817
EP  - 834
PB  - Oxford University Press
CY  - Oxford
ER  - 
TY  - JOUR
A1  - Schmid, Florian
A1  - Petersen, Gesa M.
A1  - Hooft, Emilie E. E.
A1  - Paulatto, Michele
A1  - Chrapkiewicz, Kajetan
A1  - Hensch, Martin
A1  - Dahm, Torsten
T1  - Heralds of future volcanism: Swarms of microseismicity beneath the submarine Kolumbo volcano indicate opening of near-vertical fractures exploited by ascending melts
JF  - Geochemistry, geophysics, geosystems
N2  - The Kolumbo submarine volcano in the southern Aegean (Greece) is associated with repeated seismic unrest since at least two decades and the causes of this unrest are poorly understood. We present a ten-month long microseismicity data set for the period 2006-2007. The majority of earthquakes cluster in a cone-shaped portion of the crust below Kolumbo. The tip of this cone coincides with a low Vp-anomaly at 2-4 km depth, which is interpreted as a crustal melt reservoir. Our data set includes several earthquake swarms, of which we analyze the four with the highest events numbers in detail. Together the swarms form a zone of fracturing elongated in the SW-NE direction, parallel to major regional faults. All four swarms show a general upward migration of hypocenters and the cracking front propagates unusually fast, compared to swarms in other volcanic areas. We conclude that the swarm seismicity is most likely triggered by a combination of pore-pressure perturbations and the re-distribution of elastic stresses. Fluid pressure perturbations are induced likely by obstructions in the melt conduits in a rheologically strong layer between 6 and 9 km depth. We conclude that the zone of fractures below Kolumbo is exploited by melts ascending from the mantle and filling the crustal melt reservoir. Together with the recurring seismic unrest, our study suggests that a future eruption is probable and monitoring of the Kolumbo volcanic system is highly advisable.
KW  - aegean
KW  - hellenic volcanic arc
KW  - santorini
KW  - submarine volcanism
KW  - earthquake swarms
Y1  - 2022
U6  - https://doi.org/10.1029/2022GC010420
SN  - 1525-2027
VL  - 23
IS  - 7
PB  - American Geophysical Union
CY  - Washington
ER  - 
TY  - JOUR
A1  - Ezpeleta, Miguel
A1  - Parra, Mauricio
A1  - Collo, Gilda
A1  - Wunderlin, Cecilia
A1  - Borrego, Angeles G.
A1  - Sobel, Edward
A1  - Glodny, Johannes
T1  - Thermochronometry unveils ancient thermal regimes in the NW Pampean Ranges, Argentina
BT  - from Mesozoic rifting to Miocene flat-slab subduction
JF  - Basin research
N2  - Reconstructing thermal histories in thrust belts is commonly used to infer the age and rates of thrusting and hence the driving mechanisms of orogenesis. 
In areas where ancient basins have been incorporated into the orogenic wedge, a quantitative reconstruction of the thermal history helps distinguish among potential mechanisms responsible for heating events. 

We present such a reconstruction for the Ischigualasto-Villa Union basin in the western Pampean Ranges of Argentina, where Triassic rifting and late Cretaceous-Cenozoic retroarc foreland basin development has been widely documented, including Miocene flat-slab subduction. 
We report results of organic and inorganic thermal indicators acquired along three stratigraphic sections, including vitrinite reflectance and X-ray diffractometry in claystones and new thermochronological [(apatite fission-track and apatite and zircon [U-Th]/He)] analyses. 
Despite up to 5 km-thick Cenozoic overburden and unlike previously thought, the thermal peak in the basin is not due to Cenozoic burial but occurred in the Triassic, associated with a high heat flow of up to 90 mWm(-2) and <2 km of burial, which heated the base of the Triassic strata to similar to 160 degrees C. Following exhumation, attested by the development of an unconformity between the Triassic and Late-Cretaceous-Cenozoic sequences, Cenozoic re-burial increased the temperature to similar to 110 degrees C at the base of the Triassic section and only similar to 50 degrees C 7 km upsection, suggesting a dramatic decrease in the thermal gradient. 

The onset of Cenozoic cooling occurred at similar to 10(-8) Ma, concomitant with sediment accumulation and thus preceding the latest Miocene onset of thrusting that has been independently documented by stratigraphic-cross-cutting relationships. 
We argue that the onset of cooling is associated with lithospheric refrigeration following establishment of flat-slab subduction, leading to the eastward displacement of the asthenospheric wedge beneath the South American plate. 

Our study places time and temperature constraints on flat-slab cooling that calls for a careful interpretation of exhumation signals in thrustbelts inferred from thermochronology only.
KW  - %Ro
KW  - Cenozoic flat-slab
KW  - Ischigualasto-Villa Union Basin
KW  - thermochronological modelling (AFT, AHe and ZHe)
KW  - Triassic rifting
KW  - XRD in the clay fraction
KW  - heat flow
KW  - burial
Y1  - 2022
U6  - https://doi.org/10.1111/bre.12693
SN  - 0950-091X
SN  - 1365-2117
VL  - 34
IS  - 6
SP  - 1983
EP  - 2012
PB  - Wiley
CY  - Hoboken
ER  - 
TY  - JOUR
A1  - van Geffen, Femke
A1  - Heim, Birgit
A1  - Brieger, Frederic
A1  - Geng, Rongwei
A1  - Shevtsova, Iuliia
A1  - Schulte, Luise
A1  - Stuenzi, Simone M.
A1  - Bernhardt, Nadine
A1  - Troeva, Elena I.
A1  - Pestryakova, Luidmila Agafyevna
A1  - Zakharov, Evgenii S.
A1  - Pflug, Bringfried
A1  - Herzschuh, Ulrike
A1  - Kruse, Stefan
T1  - SiDroForest: a comprehensive forest inventory of Siberian boreal forest investigations including drone-based point clouds, individually labeled trees, synthetically generated tree crowns, and Sentinel-2 labeled image patches
JF  - Earth system science data
N2  - The SiDroForest (Siberian drone-mapped forest inventory) data collection is an attempt to remedy the scarcity of forest structure data in the circumboreal region by providing adjusted and labeled tree-level and vegetation plot-level data for machine learning and upscaling purposes. We present datasets of vegetation composition and tree and plot level forest structure for two important vegetation transition zones in Siberia, Russia; the summergreen-evergreen transition zone in Central Yakutia and the tundra-taiga transition zone in Chukotka (NE Siberia). The SiDroForest data collection consists of four datasets that contain different complementary data types that together support in-depth analyses from different perspectives of Siberian Forest plot data for multi-purpose applications. i. Dataset 1 provides unmanned aerial vehicle (UAV)-borne data products covering the vegetation plots surveyed during fieldwork (Kruse et al., 2021, ). The dataset includes structure-from-motion (SfM) point clouds and red-green-blue (RGB) and red-green-near-infrared (RGN) orthomosaics. From the orthomosaics, point-cloud products were created such as the digital elevation model (DEM), canopy height model (CHM), digital surface model (DSM) and the digital terrain model (DTM). The point-cloud products provide information on the three-dimensional (3D) structure of the forest at each plot. Dataset 2 contains spatial data in the form of point and polygon shapefiles of 872 individually labeled trees and shrubs that were recorded during fieldwork at the same vegetation plots (van Geffen et al., 2021c, ). The dataset contains information on tree height, crown diameter, and species type. These tree and shrub individually labeled point and polygon shapefiles were generated on top of the RGB UVA orthoimages. The individual tree information collected during the expedition such as tree height, crown diameter, and vitality are provided in table format. This dataset can be used to link individual information on trees to the location of the specific tree in the SfM point clouds, providing for example, opportunity to validate the extracted tree height from the first dataset. The dataset provides unique insights into the current state of individual trees and shrubs and allows for monitoring the effects of climate change on these individuals in the future. Dataset 3 contains a synthesis of 10 000 generated images and masks that have the tree crowns of two species of larch ( and ) automatically extracted from the RGB UAV images in the common objects in context (COCO) format (van Geffen et al., 2021a, ). As machine-learning algorithms need a large dataset to train on, the synthetic dataset was specifically created to be used for machine-learning algorithms to detect Siberian larch species. Larix gmeliniiLarix cajanderiDataset 4 contains Sentinel-2 (S-2) Level-2 bottom-of-atmosphere processed labeled image patches with seasonal information and annotated vegetation categories covering the vegetation plots (van Geffen et al., 2021b, ). The dataset is created with the aim of providing a small ready-to-use validation and training dataset to be used in various vegetation-related machine-learning tasks. It enhances the data collection as it allows classification of a larger area with the provided vegetation classes. The SiDroForest data collection serves a variety of user communities. <br /> The detailed vegetation cover and structure information in the first two datasets are of use for ecological applications, on one hand for summergreen and evergreen needle-leaf forests and also for tundra-taiga ecotones. Datasets 1 and 2 further support the generation and validation of land cover remote-sensing products in radar and optical remote sensing. In addition to providing information on forest structure and vegetation composition of the vegetation plots, the third and fourth datasets are prepared as training and validation data for machine-learning purposes. For example, the synthetic tree-crown dataset is generated from the raw UAV images and optimized to be used in neural networks. Furthermore, the fourth SiDroForest dataset contains S-2 labeled image patches processed to a high standard that provide training data on vegetation class categories for machine-learning classification with JavaScript Object Notation (JSON) labels provided. The SiDroForest data collection adds unique insights into remote hard-to-reach circumboreal forest regions.
Y1  - 2022
U6  - https://doi.org/10.5194/essd-14-4967-2022
SN  - 1866-3508
SN  - 1866-3516
VL  - 14
IS  - 11
SP  - 4967
EP  - 4994
PB  - Copernicus
CY  - Göttingen
ER  - 
TY  - JOUR
A1  - Radosavljevic, Boris
A1  - Lantuit, Hugues
A1  - Knoblauch, Christian
A1  - Couture, Nicole
A1  - Herzschuh, Ulrike
A1  - Fritz, Michael
T1  - Arctic nearshore sediment dynamics - an example from Herschel Island - Qikiqtaruk, Canada
JF  - Journal of marine science and engineering
N2  - Increasing arctic coastal erosion rates imply a greater release of sediments and organic matter into the coastal zone. With 213 sediment samples taken around Herschel Island-Qikiqtaruk, Canadian Beaufort Sea, we aimed to gain new insights on sediment dynamics and geochemical properties of a shallow arctic nearshore zone. Spatial characteristics of nearshore sediment texture (moderately to poorly sorted silt) are dictated by hydrodynamic processes, but ice-related processes also play a role. We determined organic matter (OM) distribution and inferred the origin and quality of organic carbon by C/N ratios and stable carbon isotopes delta C-13. The carbon content was higher offshore and in sheltered areas (mean: 1.0 wt.%., S.D.: 0.9) and the C/N ratios also showed a similar spatial pattern (mean: 11.1, S.D.: 3.1), while the delta C-13 (mean: -26.4 parts per thousand VPDB, S.D.: 0.4) distribution was more complex. We compared the geochemical parameters of our study with terrestrial and marine samples from other studies using a bootstrap approach. Sediments of the current study contained 6.5 times and 1.8 times less total organic carbon than undisturbed and disturbed terrestrial sediments, respectively. Therefore, degradation of OM and separation of carbon pools take place on land and continue in the nearshore zone, where OM is leached, mineralized, or transported beyond the study area.
KW  - permafrost
KW  - Arctic Ocean
KW  - stable carbon isotopes
KW  - nitrogen
KW  - sediment
KW  - chemistry
KW  - sediment dynamics
KW  - Beaufort Sea
KW  - grain size
Y1  - 2022
U6  - https://doi.org/10.3390/jmse10111589
SN  - 2077-1312
VL  - 10
IS  - 11
PB  - MDPI
CY  - Basel
ER  - 
TY  - JOUR
A1  - Stuenzi, Simone Maria
A1  - Kruse, Stefan
A1  - Boike, Julia
A1  - Herzschuh, Ulrike
A1  - Oehme, Alexander
A1  - Pestryakova, Luidmila A.
A1  - Westermann, Sebastian
A1  - Langer, Moritz
T1  - Thermohydrological impact of forest disturbances on ecosystem-protected permafrost
JF  - Journal of geophysical research : Biogeosciences
N2  - Boreal forests cover over half of the global permafrost area and protect underlying permafrost. Boreal forest development, therefore, has an impact on permafrost evolution, especially under a warming climate. 

Forest disturbances and changing climate conditions cause vegetation shifts and potentially destabilize the carbon stored within the vegetation and permafrost. Disturbed permafrost-forest ecosystems can develop into a dry or swampy bush- or grasslands, shift toward broadleaf- or evergreen needleleaf-dominated forests, or recover to the pre-disturbance state. 

An increase in the number and intensity of fires, as well as intensified logging activities, could lead to a partial or complete ecosystem and permafrost degradation. We study the impact of forest disturbances (logging, surface, and canopy fires) on the thermal and hydrological permafrost conditions and ecosystem resilience. 

We use a dynamic multilayer canopy-permafrost model to simulate different scenarios at a study site in eastern Siberia. We implement expected mortality, defoliation, and ground surface changes and analyze the interplay between forest recovery and permafrost. We find that forest loss induces soil drying of up to 44%, leading to lower active layer thicknesses and abrupt or steady decline of a larch forest, depending on disturbance intensity. 

Only after surface fires, the most common disturbances, inducing low mortality rates, forests can recover and overpass pre-disturbance leaf area index values. We find that the trajectory of larch forests after surface fires is dependent on the precipitation conditions in the years after the disturbance. Dryer years can drastically change the direction of the larch forest development within the studied period.
KW  - permafrost
KW  - boreal forest
KW  - periglacial process
KW  - Siberia
KW  - larch forest
KW  - disturbance
Y1  - 2022
U6  - https://doi.org/10.1029/2021JG006630
SN  - 2169-8953
SN  - 2169-8961
VL  - 127
IS  - 5
PB  - American Geophysical Union
CY  - Washington
ER  - 
TY  - JOUR
A1  - Herzschuh, Ulrike
A1  - Li, Chenzhi
A1  - Boehmer, Thomas
A1  - Postl, Alexander K.
A1  - Heim, Birgit
A1  - Andreev, Andrei A.
A1  - Cao, Xianyong
A1  - Wieczorek, Mareike
A1  - Ni, Jian
T1  - LegacyPollen 1.0
BT  - a taxonomically harmonized global late Quaternary pollen dataset of 2831 records with standardized chronologies
JF  - Earth system science data : ESSD
N2  - Here we describe the LegacyPollen 1.0, a dataset of 2831 fossil pollen records with metadata, a harmonized taxonomy, and standardized chronologies. 
A total of 1032 records originate from North America, 1075 from Europe, 488 from Asia, 150 from Latin America, 54 from Africa, and 32 from the Indo-Pacific. 

The pollen data cover the late Quaternary (mostly the Holocene). The original 10 110 pollen taxa names (including variations in the notations) were harmonized to 1002 terrestrial taxa (including Cyperaceae), with woody taxa and major herbaceous taxa harmonized to genus level and other herbaceous taxa to family level. 

The dataset is valuable for synthesis studies of, for example, taxa areal changes, vegetation dynamics, human impacts (e.g., deforestation), and climate change at global or continental scales. 

The harmonized pollen and metadata as well as the harmonization table are available from PANGAEA (https://doi.org/10.1594/PANGAEA.929773; Herzschuh et al., 2021). R code for the harmonization is provided at Zenodo (https://doi.org/10.5281/zenodo.5910972; Herzschuh et al., 2022) so that datasets at a customized harmonization level can be easily established.
Y1  - 2022
U6  - https://doi.org/10.5194/essd-14-3213-2022
SN  - 1866-3508
SN  - 1866-3516
VL  - 14
IS  - 7
SP  - 3213
EP  - 3227
PB  - Copernicus
CY  - Göttingen
ER  - 
TY  - JOUR
A1  - Glückler, Ramesh
A1  - Geng, Rongwei
A1  - Grimm, Lennart
A1  - Baisheva, Izabella
A1  - Herzschuh, Ulrike
A1  - Stoof-Leichsenring, Kathleen R.
A1  - Kruse, Stefan
A1  - Andreev, Andrej Aleksandrovic
A1  - Pestryakova, Luidmila
A1  - Dietze, Elisabeth
T1  - Holocene wildfire and vegetation dynamics in Central Yakutia, Siberia, reconstructed from lake-sediment proxies
JF  - Frontiers in Ecology and Evolution
N2  - Wildfires play an essential role in the ecology of boreal forests. 
In eastern Siberia, fire activity has been increasing in recent years, challenging the livelihoods of local communities. Intensifying fire regimes also increase disturbance pressure on the boreal forests, which currently protect the permafrost beneath from accelerated degradation. 

However, long-term relationships between changes in fire regime and forest structure remain largely unknown. 
We assess past fire-vegetation feedbacks using sedimentary proxy records from Lake Satagay, Central Yakutia, Siberia, covering the past c. 10,800 years. 

Results from macroscopic and microscopic charcoal analyses indicate high amounts of burnt biomass during the Early Holocene, and that the present-day, low-severity surface fire regime has been in place since c. 4,500 years before present. 
A pollen-based quantitative reconstruction of vegetation cover and a terrestrial plant record based on sedimentary ancient DNA metabarcoding suggest a pronounced shift in forest structure toward the Late Holocene. 

Whereas the Early Holocene was characterized by postglacial open larch-birch woodlands, forest structure changed toward the modern, mixed larch-dominated closed-canopy forest during the Mid-Holocene. 

We propose a potential relationship between open woodlands and high amounts of burnt biomass, as well as a mediating effect of dense larch forest on the climate-driven intensification of fire regimes. 
Considering the anticipated increase in forest disturbances (droughts, insect invasions, and wildfires), higher tree mortality may force the modern state of the forest to shift toward an open woodland state comparable to the Early Holocene. 
Such a shift in forest structure may result in a positive feedback on currently intensifying wildfires. 

These new long-term data improve our understanding of millennial-scale fire regime changes and their relationships to changes of vegetation in Central Yakutia, where the local population is already being confronted with intensifying wildfire seasons.
KW  - fire
KW  - larch
KW  - boreal
KW  - forest
KW  - Russia
KW  - charcoal
KW  - pollen
KW  - ancient DNA
Y1  - 2022
U6  - https://doi.org/10.3389/fevo.2022.962906
SN  - 2296-701X
VL  - 10
PB  - Frontiers Media
CY  - Lausanne
ER  - 
TY  - JOUR
A1  - Song, Lina
A1  - Jie, Dongmei
A1  - Gao, Guizai
A1  - Liu, Lidan
A1  - Liu, Hongyan
A1  - Li, Dehui
A1  - Liu, Ying
T1  - Application of a topsoil phytolith dataset to quantitative paleoclimate reconstruction in Northeast China
JF  - Palaeogeography, palaeoclimatology, palaeoecology : an international journal for the geo-sciences
N2  - Although phytoliths are recognized as an important proxy for paleoenvironmental reconstruction, the quantitative relationship between phytoliths and climate is still debated. In order to provide an improved basis for phytolith-based paleoclimate reconstructions, a representative modern phytolith dataset is essential. Here, we synthesize a modern topsoil phytolith dataset for Northeast China, analyze its climatic significance, and apply it to a fossil phytolith series from the Hani peat core in Northeast China. The dataset comprises 660 topsoil phytolith assemblages from 289 sample sites. We compiled modern meteorological data to assess the quantitative relationship between the phytolith assemblages and climatic variables. Detrended correspondence analysis (DCA) and Redundancy analysis (RDA) were used to determine the dominant climatic variable influencing the phytolith distributions. The results showed that mean annual temperature (MAT) is the dominant variable controlling the spatial distribution of phytoliths, accounting for 8.91% of the total variance. Transfer function based on inverse deshrinking locally-weighted weighted averaging (LWWA_Inv) was developed for MAT (R-_boot(2) = 0.86, RMSEP = 1.02 degrees C). Applying the LWWA_Inv transfer function to fossil phytolith records from the Hani peat core enables quantitative inferences to be made about Holocene climate changes in Northeast China. Overall, combined with the LWWA_Inv method, the topsoil phytolith dataset of Northeast China can be used for reliable quantitative MAT reconstruction.
KW  - Phytoliths
KW  - Northeast China
KW  - Transfer function
KW  - paleoclimate
KW  - reconstruction
Y1  - 2022
U6  - https://doi.org/10.1016/j.palaeo.2022.111108
SN  - 0031-0182
SN  - 1872-616X
VL  - 601
PB  - Elsevier
CY  - Amsterdam
ER  - 
TY  - JOUR
A1  - Öztürk, Ugur
A1  - Bozzolan, Elisa
A1  - Holcombe, Elizabeth A.
A1  - Shukla, Roopam
A1  - Pianosi, Francesca
A1  - Wagener, Thorsten
T1  - How climate change and unplanned urban sprawl bring more landslides
JF  - Nature : the international weekly journal of science
N2  - More settlements will suffer as heavy rains and unregulated construction destabilize slopes in the tropics, models show.
KW  - Geophysics
KW  - Engineering
KW  - Climate change
KW  - Policy
Y1  - 2022
U6  - https://doi.org/10.1038/d41586-022-02141-9
SN  - 0028-0836
SN  - 1476-4687
VL  - 608
IS  - 7922
SP  - 262
EP  - 265
PB  - Nature portfolio
CY  - Berlin
ER  - 
TY  - JOUR
A1  - Cruces-Zabala, José Alejandro
A1  - Ritter, Oliver
A1  - Weckmann, Ute
A1  - Tietze, Kristina
A1  - Meqbel, Naser M.
A1  - Audemard, Franck
A1  - Schmitz, Michael
T1  - Three-dimensional magnetotelluric imaging of the Merida Andes, Venezuela
JF  - Journal of South American earth sciences
N2  - The 100 km wide Merida Andes extend from the Colombian/Venezuelan border to the Coastal Cordillera. The mountain chain and its associated major strike-slip fault systems in western Venezuela formed due to oblique convergence of the Caribbean with the South American Plates and the north-eastwards expulsion of the North Andean Block. Due to the limited knowledge of lithospheric structures related to the formation of the Merida Andes research projects have been developed to illuminate this zone with deep geophysical data. In this study, we present three-dimensional inversion of broadband magnetotelluric data, collected along a 240 km long profile crossing the Merida Andes and the Maracaibo and Barinas-Apure foreland basins. The distribution of the stations limits resolution of the model to off-profile features. Combining 3D inversion of synthetic data sets derived from 3D modelling with 3D inversion of measured data, we could derive a 10 to 15 km wide corridor with good lateral resolution to develop hypotheses about the origin of deep-reaching anomalies of high electrical conductivity. The Merida Andes appear generally as electrically resistive structures, separated by anomalies associated with the most important fault systems of the region, the Bocono and Valera faults. Sensitivity tests suggest that the Valera Fault reaches to depths of up to 12 km and the Bocono Fault to more than 35 km depth. Both structures are connected to a sizeable conductor located east of the profile at 12-15 km depth. We propose that the high conductivity associated with this off-profile conductor may be related to the detachment of the Trujillo Block. We also identified a conductive zone that correlates spatially with the location of a gravity low, possibly representing a SE tilt of the Maracaibo Triangular Block under the mountain chain to great depths (>30 km). The relevance of these tectonic blocks in our models at crustal depths seems to be consistent with proposed theories that describe the geodynamics of western Venezuela as dominated by floating blocks or orogens. Our results stress the importance of the Trujillo Block for the current tectonic evolution of western Venezuela and confirm the relevance of the Bocono Fault carrying deformation to the lower crust and upper mantle. The Barinas-Apure and the Maracaibo sedimentary basins are imaged as electrically conductive with depths of 4 to 5 km and 5 to 10 km, respectively. The Barinas-Apure basin is imaged as a simple 1D structure, in contrast to the Maracaibo Basin, where a series of conductive and resistive bodies could be related to active deformation causing the juxtaposition of older geological formations and younger basin sediments.
KW  - Magnetotellurics
KW  - Merida Andes
KW  - Geodynamics
KW  - Trujillo Block
KW  - Chain structure
KW  - Strike-slip faults
KW  - Bocono
Y1  - 2022
U6  - https://doi.org/10.1016/j.jsames.2022.103711
SN  - 0895-9811
SN  - 1873-0647
VL  - 114
PB  - Elsevier
CY  - Oxford
ER  -