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 - JOUR A1 - Schildgen, Taylor F. A1 - van der Beek, Peter A. A1 - D'Arcy, Mitch A1 - Roda-Boluda, Duna N. A1 - Orr, Elizabeth N. A1 - Wittmann, Hella T1 - Quantifying drainage-divide migration from orographic rainfall over geologic timescales BT - Sierra de Aconquija, southern Central Andes JF - Earth & planetary science letters N2 - Drainage-divide migration, controlled by rock-uplift and rainfall patterns, may play a major role in the geomorphic evolution of mountain ranges. However, divide-migration rates over geologic timescales have only been estimated by theoretical studies and remain empirically poorly constrained. Geomorphological evidence suggests that the Sierra de Aconquija, on the eastern side of the southern Central Andes, northwest Argentina, is undergoing active westward drainage-divide migration. The mountain range has been subjected to steep rock trajectories and pronounced orographic rainfall for the last several million years, presenting an ideal setting for using low-temperature thermochronometric data to explore its topographic evolution. We perform three-dimensional thermal-kinematic modeling of previously published thermochronometric data spanning the windward and leeward sides of the range to explore the most likely structural and topographic evolution of the range. We find that the data can be explained by scenarios involving drainage-divide migration alone, or by scenarios that also involve changes in the structures that have accommodated deformation through time. By combining new Be-10-derived catchment-average denudation rates with geomorphic constraints on probable fault activity, we conclude that the evolution of the range was likely dominated by west-vergent faulting on a high-angle reverse fault underlying the range, together with westward drainage-divide migration at a rate of several km per million years. Our findings place new constraints on the magnitudes and rates of drainage-divide migration in real landscapes, quantify the effects of orographic rainfall and erosion on the topographic evolution of a mountain range, and highlight the importance of considering drainage-divide migration when interpreting thermochronometer age patterns. KW - drainage-divide migration KW - landscape evolution KW - orographic rainfall KW - thermochronology KW - cosmogenic nuclides KW - Central Andes Y1 - 2022 U6 - https://doi.org/10.1016/j.epsl.2021.117345 SN - 0012-821X SN - 1385-013X VL - 579 PB - Elsevier CY - Amsterdam 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 - 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 - 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 - 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 - 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 - 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 - 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 - 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 -