TY - JOUR A1 - Zimmermann, Heike Hildegard A1 - Raschke, Elena A1 - Epp, Laura Saskia A1 - Stoof-Leichsenring, Kathleen Rosemarie A1 - Schwamborn, Georg A1 - Schirrmeister, Lutz A1 - Overduin, Pier Paul A1 - Herzschuh, Ulrike T1 - Sedimentary ancient DNA and pollen reveal the composition of plant organic matter in Late Quaternary permafrost sediments of the Buor Khaya Peninsula (north-eastern Siberia) JF - Biogeosciences N2 - Organic matter deposited in ancient, ice-rich permafrost sediments is vulnerable to climate change and may contribute to the future release of greenhouse gases; it is thus important to get a better characterization of the plant organic matter within such sediments. From a Late Quaternary permafrost sediment core from the Buor Khaya Peninsula, we analysed plant-derived sedimentary ancient DNA (sedaDNA) to identify the taxonomic composition of plant organic matter, and undertook palynological analysis to assess the environmental conditions during deposition. Using sedaDNA, we identified 154 taxa and from pollen and non-pollen palynomorphs we identified 83 taxa. In the deposits dated between 54 and 51 kyr BP, sedaDNA records a diverse low-centred polygon plant community including recurring aquatic pond vegetation while from the pollen record we infer terrestrial open-land vegetation with relatively dry environmental conditions at a regional scale. A fluctuating dominance of either terrestrial or swamp and aquatic taxa in both proxies allowed the local hydrological development of the polygon to be traced. In deposits dated between 11.4 and 9.7 kyr BP (13.4-11.1 cal kyr BP), sedaDNA shows a taxonomic turnover to moist shrub tundra and a lower taxonomic richness compared to the older samples. Pollen also records a shrub tundra community, mostly seen as changes in relative proportions of the most dominant taxa, while a decrease in taxonomic richness was less pronounced compared to sedaDNA. Our results show the advantages of using sedaDNA in combination with palynological analyses when macrofossils are rarely preserved. The high resolution of the sedaDNA record provides a detailed picture of the taxonomic composition of plant-derived organic matter throughout the core, and palynological analyses prove valuable by allowing for inferences of regional environmental conditions. Y1 - 2017 U6 - https://doi.org/10.5194/bg-14-575-2017 SN - 1726-4170 SN - 1726-4189 VL - 14 IS - 3 SP - 575 EP - 596 PB - Copernicus CY - Göttingen ER - TY - JOUR A1 - Ziegler, Moritz O. A1 - Heidbach, Oliver A1 - Zang, Arno A1 - Martinez-Garzon, Patricia A1 - Bohnhoff, Marco T1 - Estimation of the differential stress from the stress rotation angle in low permeable rock JF - Geophysical research letters N2 - Rotations of the principal stress axes are observed as a result of fluid injection into reservoirs. We use a generic, fully coupled 3-D thermo-hydro-mechanical model to investigate systematically the dependence of this stress rotation on different reservoir properties and injection scenarios. We find that permeability, injection rate, and initial differential stress are the key factors, while other reservoir properties only play a negligible role. In particular, we find that thermal effects do not significantly contribute to stress rotations. For reservoir types with usual differential stress and reservoir treatment the occurrence of significant stress rotations is limited to reservoirs with a permeability of less than approximately 10(-12)m(2). Higher permeability effectively prevents stress rotations to occur. Thus, according to these general findings, the observed principal stress axes rotation can be used as a proxy of the initial differential stress provided that rock permeability and fluid injection rate are known a priori. Y1 - 2017 U6 - https://doi.org/10.1002/2017GL073598 SN - 0094-8276 SN - 1944-8007 VL - 44 SP - 6761 EP - 6770 PB - American Geophysical Union CY - Washington ER - TY - JOUR A1 - Zhou, Bin A1 - Rybski, Diego A1 - Kropp, Jürgen T1 - The role of city size and urban form in the surface urban heat island JF - Scientific reports N2 - Urban climate is determined by a variety of factors, whose knowledge can help to attenuate heat stress in the context of ongoing urbanization and climate change. We study the influence of city size and urban form on the Urban Heat Island (UHI) phenomenon in Europe and find a complex interplay between UHI intensity and city size, fractality, and anisometry. Due to correlations among these urban factors, interactions in the multi-linear regression need to be taken into account. We find that among the largest 5,000 cities, the UHI intensity increases with the logarithm of the city size and with the fractal dimension, but decreases with the logarithm of the anisometry. Typically, the size has the strongest influence, followed by the compactness, and the smallest is the influence of the degree to which the cities stretch. Accordingly, from the point of view of UHI alleviation, small, disperse, and stretched cities are preferable. However, such recommendations need to be balanced against e.g. positive agglomeration effects of large cities. Therefore, trade-offs must be made regarding local and global aims. Y1 - 2017 U6 - https://doi.org/10.1038/s41598-017-04242-2 SN - 2045-2322 VL - 7 PB - Nature Publ. Group CY - London ER - TY - JOUR A1 - Zhilich, Snezhana A1 - Rudaya, Natalia A1 - Krivonogov, Sergei A1 - Nazarova, Larisa B. A1 - Pozdnyakov, Dmitry T1 - Environmental dynamics of the Baraba forest-steppe (Siberia) over the last 8000 years and their impact on the types of economic life of the population JF - Quaternary science reviews : the international multidisciplinary research and review journal N2 - This article offers a reconstruction of the vegetation and climate of the south-western Siberian Baraba forest-steppe area during the last ca. 8000 years. The analysis of palynological data from the sediment core of Lake Bolshie Toroki using quantitative methods has made it possible to reconstruct changes of the dominant types of vegetation and mean July air temperatures. Coniferous forests grew in the vicinity of the lake, and mean July air temperatures were similar to present-day ones between 7.9 and 7.0 kyr BP. The warmest and driest climate occurred at 7.0-5.0 kyr BP. At that time, the region had open steppe landscapes; birch groves began to spread. A cooling trend is seen after 5.5 kyr BP, when forest-steppe began to emerge. Steppe communities started to dominate again after 1.5 kyr BP. Mean July air temperatures lower than now are reconstructed for the period of 1.9-1 kyr BP, and then the temperatures became similar to present-day ones. Comparing the archaeological data on the types of economy of the population which inhabited the Baraba forest-steppe with the data on changes in the natural environment revealed a connection between the gradual transition from hunting and fishing to livestock breeding and the development of forest-steppe landscapes with a decrease in the area covered by forests. The development of the forest-steppe as an ecotonic landscape starting around 5 kyr BP might have contributed to the coexistence of several archaeological cultures with different types of economy on the same territory. (C) 2017 Elsevier Ltd. All rights reserved. KW - Holocene KW - Climate dynamics KW - Russia KW - Vegetation dynamics KW - Baraba forest-steppe KW - Archaeology KW - Transfer function Y1 - 2017 U6 - https://doi.org/10.1016/j.quascirev.2017.03.022 SN - 0277-3791 VL - 163 SP - 152 EP - 161 PB - Elsevier CY - Oxford ER - TY - JOUR A1 - Wolter, Juliane A1 - Lantuit, Hugues A1 - Herzschuh, Ulrike A1 - Stettner, Samuel A1 - Fritz, Michael T1 - Tundra vegetation stability versus lake-basin variability on the Yukon Coastal Plain (NW Canada) during the past three centuries JF - The Holocene : an interdisciplinary journal focusing on recent environmental change KW - pollen Y1 - 2017 U6 - https://doi.org/10.1177/0959683617708441 SN - 0959-6836 SN - 1477-0911 VL - 27 SP - 1846 EP - 1858 PB - Sage Publ. CY - London ER - TY - JOUR A1 - Wieczorek, Mareike A1 - Kruse, Stefan A1 - Epp, Laura Saskia A1 - Kolmogorov, Alexei A1 - Nikolaev, Anatoly N. A1 - Heinrich, Ingo A1 - Jeltsch, Florian A1 - Pestryakova, Luidmila Agafyevna A1 - Zibulski, Romy A1 - Herzschuh, Ulrike T1 - Dissimilar responses of larch stands in northern Siberia to increasing temperatures-a field and simulation based study JF - Ecology : a publication of the Ecological Society of America N2 - Arctic and alpine treelines worldwide differ in their reactions to climate change. A northward advance of or densification within the treeline ecotone will likely influence climate-vegetation feedback mechanisms. In our study, which was conducted in the Taimyr Depression in the North Siberian Lowlands, w present a combined field-and model-based approach helping us to better understand the population processes involved in the responses of the whole treeline ecotone, spanning from closed forest to single-tree tundra, to climate warming. Using information on stand structure, tree age, and seed quality and quantity from seven sites, we investigate effects of intra-specific competition and seed availability on the specific impact of recent climate warming on larch stands. Field data show that tree density is highest in the forest-tundra, and average tree size decreases from closed forest to single-tree tundra. Age-structure analyses indicate that the trees in the closed forest and forest-tundra have been present for at least similar to 240 yr. At all sites except the most southerly ones, past establishment is positively correlated with regional temperature increase. In the single-tree tundra, however, a change in growth form from krummholz to erect trees, beginning similar to 130 yr ago, rather than establishment date has been recorded. Seed mass decreases from south to north, while seed quantity increases. Simulations with LAVESI (Larix Vegetation Simulator) further suggest that relative density changes strongly in response to a warming signal in the forest-tundra while intra-specific competition limits densification in the closed forest and seed limitation hinders densification in the single-tree tundra. We find striking differences in strength and timing of responses to recent climate warming. While forest-tundra stands recently densified, recruitment is almost non-existent at the southern and northern end of the ecotone due to autecological processes. Palaeo-treelines may therefore be inappropriate to infer past temperature changes at a fine scale. Moreover, a lagged treeline response to past warming will, via feedback mechanisms, influence climate change in the future. KW - climate change KW - closed forest KW - dendroecology KW - forest change KW - latitude KW - recruitment KW - tundra KW - vegetation model Y1 - 2017 U6 - https://doi.org/10.1002/ecy.1887 SN - 0012-9658 SN - 1939-9170 VL - 98 SP - 2343 EP - 2355 PB - Wiley CY - Hoboken ER - TY - JOUR A1 - Wieczorek, Mareike A1 - Kolmogorov, Alexei A1 - Kruse, Stefan A1 - Jacobsen, Inga A1 - Nitze, Ingmar A1 - Nikolaev, Anatoly N. A1 - Heinrich, Ingo A1 - Pestryakova, Luidmila Agafyevna A1 - Herzschuh, Ulrike T1 - Disturbance-effects on treeline larch-stands in the lower Kolyma River area (NE Siberia) JF - Silva Fennica : a quarterly journal for forest science N2 - Tree stands in the boreal treeline ecotone are, in addition to climate change, impacted by disturbances such as fire, water-related disturbances and logging. We aim to understand how these disturbances affect growth, age structure, and spatial patterns of larch stands in the north-eastern Siberian treeline ecotone (lower Kolyma River region), an insufficiently researched region. Stand structure of Larix cajanderi Mayr was studied at seven sites impacted by disturbances. Maximum tree age ranged from 44 to 300 years. Young to medium-aged stands had, independent of disturbance type, the highest stand densities with over 4000 larch trees per ha. These sites also had the highest growth rates for tree height and stem diameter. Overall lowest stand densities were found in a polygonal field at the northern end of the study area, with larches growing in distinct " tree islands". At all sites, saplings are significantly clustered. Differences in fire severity led to contrasting stand structures with respect to tree, recruit, and overall stand densities. While a low severity fire resulted in low-density stands with high proportions of small and young larches, high severity fires resulted in high-density stands with high proportions of big trees. At waterdisturbed sites, stand structure varied between waterlogged and drained sites and latitude. These mixed effects of climate and disturbance make it difficult to predict future stand characteristics and the treeline position. KW - treeline KW - Larix cajanderi KW - Siberia KW - fire KW - stand structure Y1 - 2017 U6 - https://doi.org/10.14214/sf.1666 SN - 0037-5330 SN - 2242-4075 VL - 51 IS - 3 PB - The Finnish Society of Forest Science CY - Helsinki ER - TY - JOUR A1 - Weisshuhn, Peter A1 - Reckling, Moritz A1 - Stachow, Ulrich A1 - Wiggering, Hubert T1 - Supporting Agricultural Ecosystem Services through the Integration of Perennial Polycultures into Crop Rotations JF - Sustainability N2 - This review analyzes the potential role and long-term effects of field perennial polycultures (mixtures) in agricultural systems, with the aim of reducing the trade-offs between provisioning and regulating ecosystem services. First, crop rotations are identified as a suitable tool for the assessment of the long-term effects of perennial polycultures on ecosystem services, which are not visible at the single-crop level. Second, the ability of perennial polycultures to support ecosystem services when used in crop rotations is quantified through eight agricultural ecosystem services. Legume-grass mixtures and wildflower mixtures are used as examples of perennial polycultures, and compared with silage maize as a typical crop for biomass production. Perennial polycultures enhance soil fertility, soil protection, climate regulation, pollination, pest and weed control, and landscape aesthetics compared with maize. They also score lower for biomass production compared with maize, which confirms the trade-off between provisioning and regulating ecosystem services. However, the additional positive factors provided by perennial polycultures, such as reduced costs for mineral fertilizer, pesticides, and soil tillage, and a significant preceding crop effect that increases the yields of subsequent crops, should be taken into account. However, a full assessment of agricultural ecosystem services requires a more holistic analysis that is beyond the capabilities of current frameworks. KW - agroecosystem KW - assessment KW - legume-grass mixture KW - wildflower mixture KW - perennial crop KW - mixed cropping Y1 - 2017 U6 - https://doi.org/10.3390/su9122267 SN - 2071-1050 VL - 9 PB - MDPI CY - Basel ER - TY - JOUR A1 - Weis, Christopher A1 - Sternemann, Christian A1 - Cerantola, Valerio A1 - Sahle, Christoph J. A1 - Spiekermann, Georg A1 - Harder, Manuel A1 - Forov, Yury A1 - Kononov, Alexander A1 - Sakrowski, Robin A1 - Yavas, Hasan A1 - Tolan, Metin A1 - Wilke, Max T1 - Pressure driven spin transition in siderite and magnesiosiderite single crystals JF - Scientific reports Y1 - 2017 U6 - https://doi.org/10.1038/s41598-017-16733-3 SN - 2045-2322 VL - 7 PB - Nature Publ. Group CY - London ER - TY - JOUR A1 - Wang, Yongbo A1 - Bekeschus, Benjamin A1 - Handorf, Dörthe A1 - Liu, Xingqi A1 - Dallmeyer, Anne A1 - Herzschuh, Ulrike T1 - Coherent tropical-subtropical Holocene see-saw moisture patterns in the Eastern Hemisphere monsoon systems JF - Quaternary science reviews : the international multidisciplinary research and review journal N2 - The concept of a Global Monsoon (GM) has been proposed based on modern precipitation observations, but its application over a wide range of temporal scales is still under debate. Here, we present a synthesis of 268 continental paleo-moisture records collected from monsoonal systems in the Eastern Hemisphere, including the East Asian Monsoon (EAsM), the Indian Monsoon (IM), the East African Monsoon (EAfM), and the Australian Monsoon (AuM) covering the last 18,000 years. The overall pattern of late Glacial to Holocene moisture change is consistent with those inferred from ice cores and marine records. With respect to the last 10,000 years (10 ka), i.e. a period that has high spatial coverage, a Fuzzy c-Means clustering analysis of the moisture index records together with "Xie-Beni" index reveals four clusters of our data set. The paleoclimatic meaning of each cluster is interpreted considering the temporal evolution and spatial distribution patterns. The major trend in the tropical AuM, EAfM, and IM regions is a gradual decrease in moisture conditions since the early Holocene. Moisture changes in the EAsM regions show maximum index values between 8 and 6 ka. However, records located in nearby subtropical areas, i.e. in regions not influenced by the intertropical convergence zone, show an opposite trend compared to the tropical monsoon regions (AuM, EAfM and IM), i.e. a gradual increase. Analyses of modern meteorological data reveal the same spatial patterns as in the paleoclimate records such that, in times of overall monsoon strengthening, lower precipitation rates are observed in the nearby subtropical areas. We explain this pattern as the effect of a strong monsoon circulation suppressing air uplift in nearby subtropical areas, and hence hindering precipitation. By analogy to the modern system, this would mean that during the early Holocene strong monsoon period, the intensified ascending airflows within the monsoon domains led to relatively weaker ascending or even descending airflows in the adjacent subtropical regions, resulting in a precipitation deficit compared to the late Holocene. Our conceptual model therefore integrates regionally contrasting moisture changes into the Global Monsoon hypothesis. (C) 2017 Elsevier Ltd. All rights reserved. KW - Global monsoon KW - Holocene KW - Eastern hemisphere KW - Moisture evolution Y1 - 2017 U6 - https://doi.org/10.1016/j.quascirev.2017.06.006 SN - 0277-3791 VL - 169 SP - 231 EP - 242 PB - Elsevier CY - Oxford ER - TY - JOUR A1 - Wambura, Frank Joseph A1 - Dietrich, Ottfried A1 - Lischeid, Gunnar T1 - Evaluation of Spatio-Temporal Patterns of Remotely Sensed Evapotranspiration to Infer Information about Hydrological Behaviour in a Data-Scarce Region JF - Water N2 - Information about the hydrological behaviour of a river basin prior to setting up, calibrating and validating a distributed hydrological model requires extensive datasets that are hardly available for many parts of the world due to insufficient monitoring networks. In this study, the focus was on prevailing spatio-temporal patterns of remotely sensed evapotranspiration (ET) that enabled conclusions to be drawn about the hydrological behaviour and spatial peculiarities of a river basin at rather high spatial resolution. The prevailing spatio-temporal patterns of ET were identified using a principal component analysis of a time series of 644 images of MODIS ET covering the Wami River basin (Tanzania) between the years 2000 and 2013. The time series of the loadings on the principal components were analysed for seasonality and significant long-term trends. The spatial patterns of principal component scores were tested for significant correlation with elevations and slopes, and for differences between different soil texture and land use classes. The results inferred that the temporal and spatial patterns of ET were related to those of preceding rainfalls. At the end of the dry season, high ET was maintained only in areas of shallow groundwater and in cloud forest nature reserves. A region of clear reduction of ET in the long-term was related to massive land use change. The results also confirmed that most soil texture and land use classes differed significantly. Moreover, ET was exceptionally high in natural forests and loam soil, and very low in bushland and sandy-loam soil. Clearly, this approach has shown great potential of publicly available remote sensing data in providing a sound basis for water resources management as well as for distributed hydrological models in data-scarce river basins at lower latitudes. KW - evapotranspiration KW - hydrological behaviour KW - land cover change KW - MODIS ET KW - principal component analysis KW - shallow groundwater Y1 - 2017 U6 - https://doi.org/10.3390/w9050333 SN - 2073-4441 VL - 9 SP - 297 EP - 315 PB - MDPI CY - Basel ER - TY - JOUR A1 - Vormoor, Klaus Josef A1 - Rossler, Ole A1 - Bürger, Gerd A1 - Bronstert, Axel A1 - Weingartner, Rolf T1 - When timing matters-considering changing temporal structures in runoff response surfaces JF - Climatic change : an interdisciplinary, intern. journal devoted to the description, causes and implications of climatic change N2 - Scenario-neutral response surfaces illustrate the sensitivity of a simulated natural system, represented by a specific impact variable, to systematic perturbations of climatic parameters. This type of approach has recently been developed as an alternative to top-down approaches for the assessment of climate change impacts. A major limitation of this approach is the underrepresentation of changes in the temporal structure of the climate input data (i.e., the seasonal and day-to-day variability) since this is not altered by the perturbation. This paper presents a framework that aims to examine this limitation by perturbing both observed and projected climate data time series for a future period, which both serve as input into a hydrological model (the HBV model). The resulting multiple response surfaces are compared at a common domain, the standardized runoff response surface (SRRS). We apply this approach in a case study catchment in Norway to (i) analyze possible changes in mean and extreme runoff and (ii) quantify the influence of changes in the temporal structure represented by 17 different climate input sets using linear mixed-effect models. Results suggest that climate change induced increases in mean and peak flow runoff and only small changes in low flow. They further suggest that the effect of the different temporal structures of the climate input data considerably affects low flows and floods (at least 21% influence), while it is negligible for mean runoff. Y1 - 2017 U6 - https://doi.org/10.1007/s10584-017-1940-1 SN - 0165-0009 SN - 1573-1480 VL - 142 SP - 213 EP - 226 PB - Springer CY - Dordrecht ER - TY - JOUR A1 - Vogeli, Natalie A1 - Najman, Yani A1 - van der Beek, Pieter A. A1 - Huyghe, Pascale A1 - Wynn, Peter M. A1 - Govin, Gwladys A1 - van der Veen, Iris A1 - Sachse, Dirk T1 - Lateral variations in vegetation in the Himalaya since the Miocene and implications for climate evolution JF - Earth & planetary science letters N2 - The Himalaya has a major influence on global and regional climate, in particular on the Asian monsoon system. The foreland basin of the Himalaya contains a record of tectonics and paleoclimate since the Miocene. Previous work on the evolution of vegetation and climate has focused on the central and western Himalaya, where a shift from C3 to C4 vegetation has been observed at similar to 7 Ma and linked to increased seasonality, but the climatic evolution of the eastern part of the orogen is less well understood. In order to track vegetation as a marker of monsoon intensity and seasonality, we analyzed delta C-13 and 8180 values of soil carbonate and associated delta C-13 values of bulk organic carbon from previously dated sedimentary sections exposing the syn-orogenic detrital Dharamsala and Siwalik Groups in the west, and, for the first time, the Siwalik Group in the east of the Himalayan foreland basin. Sedimentary records span from 20 to 1 Myr in the west (Joginder Nagar, Jawalamukhi, and Haripur Kolar sections) and from 13 to 1 Myr in the east (Kameng section), respectively. The presence of soil carbonate in the west and its absence in the east is a first indication of long-term lateral climatic variation, as soil carbonate requires seasonally arid conditions to develop. delta C-13 values in soil carbonate show a shift from around -10 parts per thousand to -2 parts per thousand at similar to 7 Ma in the west, which is confirmed by delta C-13 analyses on bulk organic carbon that show a shift from around -23 parts per thousand to -19 parts per thousand at the same time. Such a shift in isotopic values is likely to be associated with a change from C3 to C4 vegetation. In contrast, delta C-13 values of bulk organic carbon remain at 23 parts per thousand o in the east. Thus, our data show that the current east -west variation in climate was established at similar to 7 Ma. We propose that the regional change towards a more seasonal climate in the west is linked to a decrease of the influence of the Westerlies, delivering less winter precipitation to the western Himalaya, while the east remained annually humid due to its proximity to the monsoonal moisture source. (C) 2017 Elsevier B.V. All rights reserved. KW - Himalaya KW - stable carbon isotopes KW - paleovegetation KW - Siwalik KW - pre-Siwalik KW - monsoon Y1 - 2017 U6 - https://doi.org/10.1016/j.epsl.2017.04.037 SN - 0012-821X SN - 1385-013X VL - 471 SP - 1 EP - 9 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Vogel, Kristin A1 - Ozturk, Ugur A1 - Riemer, Adrian A1 - Laudan, Jonas A1 - Sieg, Tobias A1 - Wendi, Dadiyorto A1 - Agarwal, Ankit A1 - Roezer, Viktor A1 - Korup, Oliver A1 - Thieken, Annegret T1 - Die Sturzflut von Braunsbach am 29. Mai 2016 – Entstehung, Ablauf und Schäden eines „Jahrhundertereignisses“ T1 - The Braunsbach Flashflood of Mai 29th, 2016-Origin, Pathways and Impacts of an Extreme Hydro-Meteorological Event BT - Teil 2: Geomorphologische Prozesse und Schadensanalyse BT - Part 2: Geomorphological Processes and Damage Analysis JF - Hydrologie und Wasserbewirtschaftung N2 - Am Abend des 29. Mai 2016 wurde der Ort Braunsbach im Landkreis Schwäbisch-Hall (Baden-Württemberg) von einer Sturzflut getroffen, bei der mehrere Häuser stark beschädigt oder zerstört wurden. Die Sturzflut war eine der Unwetterfolgen, die im Frühsommer 2016 vom Tiefdruckgebiet Elvira ausgelöst wurden. Der vorliegende Bericht ist der zweite Teil einer Doppelveröffentlichung, welche die Ergebnisse zur Untersuchung des Sturzflutereignisses im Rahmen des DFG-Graduiertenkollegs “Naturgefahren und Risiken in einer sich verändernden Welt” (NatRiskChange, GRK 2043/1) der Universität Potsdam präsentiert. Während Teil 1 die meteorologischen und hydrologischen Ereignisse analysiert, fokussiert Teil 2 auf die geomorphologischen Prozesse und die verursachten Gebäudeschäden. Dazu wurden Ursprung und Ausmaß des während des Sturzflutereignisses mobilisierten und in den Ort getragenen Materials untersucht. Des Weiteren wurden zu 96 betroffenen Gebäuden Daten zum Schadensgrad sowie Prozess- und Gebäudecharakteristika aufgenommen und ausgewertet. Die Untersuchungen zeigen, dass bei der Betrachtung von Hochwassergefährdung die Berücksichtigung von Sturzfluten und ihrer speziellen Charakteristika, wie hoher Feststofftransport und sprunghaftes Verhalten insbesondere in bebautem Gelände, wesentlich ist, um effektive Schutzmaßnahmen ergreifen zu können. N2 - A severe flash flood event hit the town of Braunsbach (Baden-Wurttemberg, Germany) on the evening of May 29, 2016, heavily damaging and destroying several dozens of buildings. It was only one of several disastrous events in Central Europe caused by the low-pressure system "Elvira". The DFG Graduate School "Natural hazards and risks in a changing world" (NatRiskChange, GRK 2043/1) at the University of Potsdam investigated the Braunsbach flash flood as a recent showcase for catastrophic events triggered by severe weather. This contribution is part two of a back-to-back publication on the results of this storm event. While part 1 analyses the meteorological and hydrological situation, part 2 concentrates on the geomorphological aspects and damage to buildings. The study outlines the origin and amount of material that was mobilized and transported into the town by the flood, and analyses damage data collected for 96 affected buildings, describing the degree of impact, underlying processes, and building characteristics. Due to the potentially high sediment load of flash floods and their non-steady and non-uniform flow especially in built-up areas, the damaging processes differ from those of clear water floods. The results underline the need to consider flash floods and their specific behaviour in flood hazard assessments. KW - flash flood KW - flood risk KW - damaging processes KW - debris flow KW - erosion KW - landslides KW - Braunsbach KW - Sturzflut KW - Hochwassergefährdung KW - Schadensprozesse KW - Erosion KW - Hangrutschungen Y1 - 2017 U6 - https://doi.org/10.5675/HyWa_2017,3_2 SN - 1439-1783 VL - 61 IS - 3 SP - 163 EP - 175 PB - Bundesanst. für Gewässerkunde CY - Koblenz ER - TY - JOUR A1 - van der Meij, Marijn W. A1 - Temme, Arnaud J. A. M. A1 - Wallinga, J. A1 - Hierold, W. A1 - Sommer, Michael T1 - Topography reconstruction of eroding landscapes - A case study from a hummocky ground moraine (CarboZALF-D) JF - Geomorphology : an international journal on pure and applied geomorphology N2 - Erosion processes, aggravated by human activity, have a large impact on the spatial variation of soil and topographic properties. Knowledge of the topography prior to human-induced erosion (paleotopography) in naturally stable landscapes is valuable for identifying vulnerable landscape positions and is required as starting point for erosion modelling exercises. However, developing accurate reconstructions of paleotopography provide a major challenge for geomorphologists. Here, we present a set of paleotopographies for a closed kettle hole catchment in north-east Germany (4 ha), obtained through different reconstruction approaches. Current soil and colluvium thickness, estimated from a dataset of 264 soil descriptions using Ordinary Kriging, were used as input for a mass balance, or were compared with a set of undisturbed soil thicknesses to estimate the amount of erosion. The performance of the different approaches was assessed with cross-validation and the count of mispredicted eroded, depositional or stable landscape positions. The paleotopographic reconstruction approach based on the average thickness of undisturbed soils in the study area showed the best performance. This thickness (1.00 m) is comparable to the average undisturbed soil thickness in the region and in line with global correlations of soil thickness as a function of rainfall and initial CaCO3 content. The performance of the different approaches depended more on mispredictions of landscape position due to the assumption of a spatially constant initial soil depth than on small variations in this depth. To conclude, we mention several methodological and practical points of attention for future topography reconstruction studies, concerning data quality and availability, spatial configuration of data and other processes affecting topography. (C) 2017 Elsevier B.V. All rights reserved. KW - Topography reconstruction KW - Erosion KW - Tillage KW - Landscape change Y1 - 2017 U6 - https://doi.org/10.1016/j.geomorph.2017.08.015 SN - 0169-555X SN - 1872-695X VL - 295 SP - 758 EP - 772 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Tötzke, Christian A1 - Kardjilov, Nikolay A1 - Manke, Ingo A1 - Oswald, Sascha T1 - Capturing 3D Water Flow in Rooted Soil by Ultra-fast Neutron Tomography JF - Scientific reports N2 - Water infiltration in soil is not only affected by the inherent heterogeneities of soil, but even more by the interaction with plant roots and their water uptake. Neutron tomography is a unique non-invasive 3D tool to visualize plant root systems together with the soil water distribution in situ. So far, acquisition times in the range of hours have been the major limitation for imaging 3D water dynamics. Implementing an alternative acquisition procedure we boosted the speed of acquisition capturing an entire tomogram within 10 s. This allows, for the first time, tracking of a water front ascending in a rooted soil column upon infiltration of deuterated water time-resolved in 3D. Image quality and resolution could be sustained to a level allowing for capturing the root system in high detail. Good signal-to-noise ratio and contrast were the key to visualize dynamic changes in water content and to localize the root uptake. We demonstrated the ability of ultra-fast tomography to quantitatively image quick changes of water content in the rhizosphere and outlined the value of such imaging data for 3D water uptake modelling. The presented method paves the way for time-resolved studies of various 3D flow and transport phenomena in porous systems. Y1 - 2017 U6 - https://doi.org/10.1038/s41598-017-06046-w SN - 2045-2322 VL - 7 PB - Macmillan Publishers Limited CY - London ER - TY - JOUR A1 - Tronicke, Jens A1 - Paasche, Hendrik T1 - Integrated interpretation of 2D ground-penetrating radar, P-, and S-wave velocity models in terms of petrophysical properties BT - assessing uncertainties related to data inversion and petrophysical relations JF - Interpretation : a journal of subsurface characterization N2 - Near-surface geophysical techniques are extensively used in a variety of engineering, environmental, geologic, and hydrologic applications. While many of these applications ask for detailed, quantitative models of selected material properties, geophysical data are increasingly used to estimate such target properties. Typically, this estimation procedure relies on a two-step workflow including (1) the inversion of geophysical data and (2) the petrophysical translation of the inverted parameter models into the target properties. Standard deterministic implementations of such a quantitative interpretation result in a single best-estimate model, often without considering and propagating the uncertainties related to the two steps. We address this problem by using a rather novel, particle-swarm-based global joint strategy for data inversion and by implementing Monte Carlo procedures for petrophysical property estimation. We apply our proposed workflow to crosshole ground-penetrating radar, P-, and S-wave data sets collected at a well-constrained test site for a detailed geotechnical characterization of unconsolidated sands. For joint traveltime inversion, the chosen global approach results in ensembles of acceptable velocity models, which are analyzed to appraise inversion-related uncertainties. Subsequently, the entire ensembles of inverted velocity models are considered to estimate selected petrophysical properties including porosity, bulk density, and elastic moduli via well-established petrophysical relations implemented in a Monte Carlo framework. Our results illustrate the potential benefit of such an advanced interpretation strategy; i.e., the proposed workflow allows to study how uncertainties propagate into the finally estimated property models, while concurrently we are able to study the impact of uncertainties in the used petrophysical relations (e.g., the influence of uncertain, user-specified parameters). We conclude that such statistical approaches for the quantitative interpretation of geophysical data can be easily extended and adapted to other applications and geophysical methods and might be an important step toward increasing the popularity and acceptance of geophysical tools in engineering practice. Y1 - 2017 U6 - https://doi.org/10.1190/INT-2016-0081.1 SN - 2324-8858 SN - 2324-8866 VL - 5 IS - 1 SP - T121 EP - T130 PB - Society of Exploration Geophysicists CY - Tulsa ER - TY - JOUR A1 - Toy, Virginia Gail A1 - Sutherland, Rupert A1 - Townend, John A1 - Allen, Michael J. A1 - Becroft, Leeza A1 - Boles, Austin A1 - Boulton, Carolyn A1 - Carpenter, Brett A1 - Cooper, Alan A1 - Cox, Simon C. A1 - Daube, Christopher A1 - Faulkner, D. R. A1 - Halfpenny, Angela A1 - Kato, Naoki A1 - Keys, Stephen A1 - Kirilova, Martina A1 - Kometani, Yusuke A1 - Little, Timothy A1 - Mariani, Elisabetta A1 - Melosh, Benjamin A1 - Menzies, Catriona D. A1 - Morales, Luiz A1 - Morgan, Chance A1 - Mori, Hiroshi A1 - Niemeijer, Andre A1 - Norris, Richard A1 - Prior, David A1 - Sauer, Katrina A1 - Schleicher, Anja Maria A1 - Shigematsu, Norio A1 - Teagle, Damon A. H. A1 - Tobin, Harold A1 - Valdez, Robert A1 - Williams, Jack A1 - Yeo, Samantha A1 - Baratin, Laura-May A1 - Barth, Nicolas A1 - Benson, Adrian A1 - Boese, Carolin A1 - Célérier, Bernard A1 - Chamberlain, Calum J. A1 - Conze, Ronald A1 - Coussens, Jamie A1 - Craw, Lisa A1 - Doan, Mai-Linh A1 - Eccles, Jennifer A1 - Grieve, Jason A1 - Grochowski, Julia A1 - Gulley, Anton A1 - Howarth, Jamie A1 - Jacobs, Katrina A1 - Janku-Capova, Lucie A1 - Jeppson, Tamara A1 - Langridge, Robert A1 - Mallyon, Deirdre A1 - Marx, Ray A1 - Massiot, Cécile A1 - Mathewson, Loren A1 - Moore, Josephine A1 - Nishikawa, Osamu A1 - Pooley, Brent A1 - Pyne, Alex A1 - Savage, Martha K. A1 - Schmitt, Doug A1 - Taylor-Offord, Sam A1 - Upton, Phaedra A1 - Weaver, Konrad C. A1 - Wiersberg, Thomas A1 - Zimmer, Martin T1 - Bedrock geology of DFDP-2B, central Alpine Fault, New Zealand JF - New Zealand journal of geology and geophysics : an international journal of the geoscience of New Zealand, the Pacific Rim, and Antarctica ; NZJG N2 - During the second phase of the Alpine Fault, Deep Fault Drilling Project (DFDP) in the Whataroa River, South Westland, New Zealand, bedrock was encountered in the DFDP-2B borehole from 238.5–893.2 m Measured Depth (MD). Continuous sampling and meso- to microscale characterisation of whole rock cuttings established that, in sequence, the borehole sampled amphibolite facies, Torlesse Composite Terrane-derived schists, protomylonites and mylonites, terminating 200–400 m above an Alpine Fault Principal Slip Zone (PSZ) with a maximum dip of 62°. The most diagnostic structural features of increasing PSZ proximity were the occurrence of shear bands and reduction in mean quartz grain sizes. A change in composition to greater mica:quartz + feldspar, most markedly below c. 700 m MD, is inferred to result from either heterogeneous sampling or a change in lithology related to alteration. Major oxide variations suggest the fault-proximal Alpine Fault alteration zone, as previously defined in DFDP-1 core, was not sampled. KW - Alpine Fault KW - New Zealand KW - scientific drilling KW - mylonite KW - cataclasite Y1 - 2017 U6 - https://doi.org/10.1080/00288306.2017.1375533 SN - 0028-8306 SN - 1175-8791 VL - 60 IS - 4 SP - 497 EP - 518 PB - Taylor & Francis CY - Abingdon ER - TY - JOUR A1 - Totz, Sonja Juliana A1 - Tziperman, Eli A1 - Coumou, Dim A1 - Pfeiffer, Karl A1 - Cohen, Judah T1 - Winter precipitation forecast in the European and mediterranean regions using cluster analysis JF - Geophysical research letters N2 - The European climate is changing under global warming, and especially the Mediterranean region has been identified as a hot spot for climate change with climate models projecting a reduction in winter rainfall and a very pronounced increase in summertime heat waves. These trends are already detectable over the historic period. Hence, it is beneficial to forecast seasonal droughts well in advance so that water managers and stakeholders can prepare to mitigate deleterious impacts. We developed a new cluster-based empirical forecast method to predict precipitation anomalies in winter. This algorithm considers not only the strength but also the pattern of the precursors. We compare our algorithm with dynamic forecast models and a canonical correlation analysis-based prediction method demonstrating that our prediction method performs better in terms of time and pattern correlation in the Mediterranean and European regions. KW - precipitation anomaly KW - seasonal forecast KW - cluster analysis Y1 - 2018 U6 - https://doi.org/10.1002/2017GL075674 SN - 0094-8276 SN - 1944-8007 VL - 44 SP - 12418 EP - 12426 PB - American Geophysical Union CY - Washington ER - TY - JOUR A1 - Tofelde, Stefanie A1 - Schildgen, Taylor F. A1 - Savi, Sara A1 - Pingel, Heiko A1 - Wickert, Andrew D. A1 - Bookhagen, Bodo A1 - Wittmann, Hella A1 - Alonso, Ricardo N. A1 - Cottle, John A1 - Strecker, Manfred T1 - 100 kyr fluvial cut-and-fill terrace cycles since the Middle Pleistocene in the southern Central Andes, NW Argentina JF - Earth & planetary science letters N2 - Fluvial fill terraces in intermontane basins are valuable geomorphic archives that can record tectonically and/or climatically driven changes of the Earth-surface process system. However, often the preservation of fill terrace sequences is incomplete and/or they may form far away from their source areas, complicating the identification of causal links between forcing mechanisms and landscape response, especially over multi-millennial timescales. The intermontane Toro Basin in the southern Central Andes exhibits at least five generations of fluvial terraces that have been sculpted into several-hundred-meter-thick Quaternary valley-fill conglomerates. New surface-exposure dating using nine cosmogenic Be-10 depth profiles reveals the successive abandonment of these terraces with a 100 kyr cyclicity between 75 +/- 7 and 487 +/- 34 ka. Depositional ages of the conglomerates, determined by four Al-26/Be-10 burial samples and U-Pb zircon ages of three intercalated volcanic ash beds, range from 18 +/- 141 to 936 +/- 170 ka, indicating that there were multiple cut-and-fill episodes. Although the initial onset of aggradation at similar to 1 Ma and the overall net incision since ca. 500 ka can be linked to tectonic processes at the narrow basin outlet, the superimposed 100 kyr cycles of aggradation and incision are best explained by eccentricity-driven climate change. Within these cycles, the onset of river incision can be correlated with global cold periods and enhanced humid phases recorded in paleoclimate archives on the adjacent Bolivian Altiplano, whereas deposition occurred mainly during more arid phases on the Altiplano and global interglacial periods. We suggest that enhanced runoff during global cold phases - due to increased regional precipitation rates, reduced evapotranspiration, or both - resulted in an increased sediment-transport capacity in the Toro Basin, which outweighed any possible increases in upstream sediment supply and thus triggered incision. Compared with two nearby basins that record precessional (21-kyr) and long-eccentricity (400-kyr) forcing within sedimentary and geomorphic archives, the recorded cyclicity scales with the square of the drainage basin length. (C) 2017 Elsevier B.V. All rights reserved. KW - Be-10 depth-profiles KW - surface inflation KW - aggradation-incision cycles KW - glacial-interglacial cycles KW - landscape response to climate change KW - Eastern Cordillera Y1 - 2017 U6 - https://doi.org/10.1016/j.epsl.2017.06.001 SN - 0012-821X SN - 1385-013X VL - 473 SP - 141 EP - 153 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Toetzke, Christian A1 - Kardjilov, Nikolay A1 - Manke, Ingo A1 - Oswald, Sascha T1 - Capturing 3D Water Flow in Rooted Soil by Ultra-fast Neutron Tomography JF - Scientific reports N2 - Water infiltration in soil is not only affected by the inherent heterogeneities of soil, but even more by the interaction with plant roots and their water uptake. Neutron tomography is a unique non-invasive 3D tool to visualize plant root systems together with the soil water distribution in situ. So far, acquisition times in the range of hours have been the major limitation for imaging 3D water dynamics. Implementing an alternative acquisition procedure we boosted the speed of acquisition capturing an entire tomogram within 10 s. This allows, for the first time, tracking of a water front ascending in a rooted soil column upon infiltration of deuterated water time-resolved in 3D. Image quality and resolution could be sustained to a level allowing for capturing the root system in high detail. Good signal-to-noise ratio and contrast were the key to visualize dynamic changes in water content and to localize the root uptake. We demonstrated the ability of ultra-fast tomography to quantitatively image quick changes of water content in the rhizosphere and outlined the value of such imaging data for 3D water uptake modelling. The presented method paves the way for time-resolved studies of various 3D flow and transport phenomena in porous systems. Y1 - 2017 U6 - https://doi.org/10.1038/s41598-017-06046-w SN - 2045-2322 VL - 7 PB - Nature Publ. Group CY - London ER - TY - JOUR A1 - Tian, Fang A1 - Cao, Xianyong A1 - Dallmeyer, Anne A1 - Zhao, Yan A1 - Ni, Jian A1 - Herzschuh, Ulrike T1 - Pollen-climate relationships in time (9 ka, 6 ka, 0 ka) and space (upland vs. lowland) in eastern continental Asia JF - Quaternary science reviews : the international multidisciplinary research and review journal N2 - Temporal and spatial stability of the vegetation climate relationship is a basic ecological assumption for pollen-based quantitative inferences of past climate change and for predicting future vegetation. We explore this assumption for the Holocene in eastern continental Asia (China, Mongolia). Boosted regression trees (BRT) between fossil pollen taxa percentages (Abies, Artemisia, Betula, Chenopodiaceae, Cyperaceae, Ephedra, Picea, Pinus, Poaceae and Quercus) and climate model outputs of mean annual precipitation (P-ann) and mean temperature of the warmest month (Mt(wa)) for 9 and 6 ka (ka = thousand years before present) were set up and results compared to those obtained from relating modern pollen to modern climate. Overall, our results reveal only slight temporal differences in the pollen climate relationships. Our analyses suggest that the importance of P-ann compared with Mt(wa) for taxa distribution is higher today than it was at 6 ka and 9 ka. In particular, the relevance of P-ann for Picea and Pinus increases and has become the main determinant. This change in the climate tree pollen relationship parallels a widespread tree pollen decrease in north-central China and the eastern Tibetan Plateau. We assume that this is at least partly related to vegetation climate disequilibrium originating from human impact. Increased atmospheric CO2 concentration may have permitted the expansion of moisture-loving herb taxa (Cyperaceae and Poaceae) during the late Holocene into arid/semi-arid areas. We furthermore find that the pollen climate relationship between north-central China and the eastern Tibetan Plateau is generally similar, but that regional differences are larger than temporal differences. In summary, vegetation climate relationships in China are generally stable in space and time, and pollen-based climate reconstructions can be applied to the Holocene. Regional differences imply the calibration-set should be restricted spatially. KW - Boosted regression trees KW - China KW - Holocene KW - Niche stability KW - Pollen-climate relationship KW - Uniformitarianism Y1 - 2016 U6 - https://doi.org/10.1016/j.quascirev.2016.11.027 SN - 0277-3791 VL - 156 SP - 1 EP - 11 PB - Elsevier CY - Oxford ER - TY - JOUR A1 - Thieken, Annegret T1 - Contributions of flood insurance toeEnhance resilience-findings from Germany BT - Findings from Germany JF - Urban Disaster Resilience and Security N2 - In 2002, a severe flood caused financial losses of EUR 11.6 billion in Germany and triggered many changes in flood risk management. This chapter focuses on flood insurance, which is a voluntary supplementary insurance in Germany: it is explored how flood insurance has contributed to enhance resilience of flood-prone residents. The analyses are based on empirical data collected by post-event surveys in the federal states of Saxony and Bavaria and refer to the three pillars upon which the concept of flood resilience usually builds in the natural hazards context: recovery, adaptive capacity and resistance. Overall, the penetration of flood insurance has increased since 2002 and there is strong empirical evidence that losses of insured residents are more often and better compensated than those of uninsured despite the provision of governmental financial disaster assistance after big floods. This facilitation of recovery is, however, not the only contribution to flood resilience. Insured residents tend to invest more in further flood mitigation measures at their properties than uninsured. Obviously, flood insurance is embedded in a complex safety strategy of property owners that needs more investigation in order to be addressed more effectively in risk communication and integrated risk management strategies. KW - Flood losses KW - Recovery KW - Climate change adaptation Saxony KW - Bavaria Y1 - 2017 SN - 978-3-319-68606-6 SN - 978-3-319-68605-9 U6 - https://doi.org/10.1007/978-3-319-68606-6_9 SN - 2365-757X SP - 129 EP - 144 PB - Springer CY - Cham ER - TY - JOUR A1 - Thiede, Rasmus Christoph A1 - Robert, Xavier A1 - Stuebner, Konstanze A1 - Dey, Saptarshi A1 - Faruhn, Johannes T1 - Sustained out-of-sequence shortening along a tectonically active segment of the Main Boundary thrust: The Dhauladhar Range in the northwestern Himalaya JF - Lithosphere N2 - Competing hypotheses suggest that Himalayan topography is sustained and the plate convergence is accommodated either solely along the basal decollement, the Main Himalayan thrust (MHT), or more broadly, across multiple thrust faults. In the past, structural, geomorphic, and geodetic data of the Nepalese Himalaya have been used to constrain the geometry of the MHT and its shallow frontal thrust fault, known as Main Frontal thrust (MFT). The MHT flattens at depth and connects to a hinterland mid-crustal, steeper thrust ramp, located similar to 100 km north of the deformation front. There, the present-day convergence across the Himalaya is mostly accommodated by slip along the MFT. Despite a general agreement that in Nepal most of the shortening is accommodated along the MHT, some researchers have suggested the occurrence of persistent out-of-sequence shortening on interior faults near the Main Central thrust (MCT). Along the northwest Himalaya, in contrast, some of these characteristics of central Nepal are missing, suggesting along-strike variation of wedge deformation and MHT fault geometry. Here we present new field observations and seven zircon (U-Th)/He (ZHe) cooling ages combined with existing low-temperature data sets. In agreement with our previous findings, we suggest that the transect of cooling age patterns across the frontal Dhauladhar Range reveals that the Main Boundary thrust (MBT) is a primary fault, which has uplifted and sustained this spectacular mountain front since at least the late Miocene. Our results suggest that the MBT forms an similar to 40-km-long fault ramp before it soles into the MHT, and motion along it has exhumed rocks from depth of similar to 8-10 km. New three-dimensional thermokinematic modeling (using Pecube finite-element code) reveals that the observed ZHe and apatite fission track cooling ages can only be explained by sustained mean MBT slip rates between similar to 2.6 and 3.5 mm a(-1) since at least 8 Ma, which corresponds to a horizontal shortening rate of similar to 1.7-2.4 mm a(-1). We propose that the MBT is active today, despite a lack of definitive field or seismogenic evidence, and continues to accommodate crustal shorting by out-of-sequence faulting. Assuming that present-day geodetic shorting rates (similar to 14 +/- 2 mm a(-1)) across the northwest Himalaya have been sustained over geologic time scales, this implies that the MBT accommodated similar to 15% of the total Himalayan convergence since its onset. Furthermore, our modeling results imply that the MHT is missing a hinterland mid-crustal ramp further north. Y1 - 2017 U6 - https://doi.org/10.1130/L630.1 SN - 1941-8264 SN - 1947-4253 VL - 9 SP - 715 EP - 725 PB - American Institute of Physics CY - Boulder ER - TY - JOUR A1 - Tanyas, Hakan A1 - van Westen, Cees J. A1 - Allstadt, Kate E. A1 - Jessee, M. Anna Nowicki A1 - Gorum, Tolga A1 - Jibson, Randall W. A1 - Godt, Jonathan W. A1 - Sato, Hiroshi P. A1 - Schmitt, Robert G. A1 - Marc, Odin A1 - Hovius, Niels T1 - Presentation and Analysis of a Worldwide Database of Earthquake-Induced Landslide Inventories JF - Journal of geophysical research : Earth surface N2 - Earthquake-induced landslide (EQIL) inventories are essential tools to extend our knowledge of the relationship between earthquakes and the landslides they can trigger. Regrettably, such inventories are difficult to generate and therefore scarce, and the available ones differ in terms of their quality and level of completeness. Moreover, access to existing EQIL inventories is currently difficult because there is no centralized database. To address these issues, we compiled EQIL inventories from around the globe based on an extensive literature study. The database contains information on 363 landslide-triggering earthquakes and includes 66 digital landslide inventories. To make these data openly available, we created a repository to host the digital inventories that we have permission to redistribute through the U.S. Geological Survey ScienceBase platform. It can grow over time as more authors contribute their inventories. We analyze the distribution of EQIL events by time period and location, more specifically breaking down the distribution by continent, country, and mountain region. Additionally, we analyze frequency distributions of EQIL characteristics, such as the approximate area affected by landslides, total number of landslides, maximum distance from fault rupture zone, and distance from epicenter when the fault plane location is unknown. For the available digital EQIL inventories, we examine the underlying characteristics of landslide size, topographic slope, roughness, local relief, distance to streams, peak ground acceleration, peak ground velocity, and Modified Mercalli Intensity. Also, we present an evaluation system to help users assess the suitability of the available inventories for different types of EQIL studies and model development. Y1 - 2017 U6 - https://doi.org/10.1002/2017JF004236 SN - 2169-9003 SN - 2169-9011 VL - 122 SP - 1991 EP - 2015 PB - American Geophysical Union CY - Washington ER - TY - JOUR A1 - Syrykh, Lydmila S. A1 - Nazarova, Larisa B. A1 - Herzschuh, Ulrike A1 - Subetto, D. A. A1 - Grekov, I. M. T1 - Reconstruction of palaeoecological and palaeoclimatic conditions of the Holocene in the south of the Taimyr according to an analysis of lake sediments JF - Contemporary Problems of Ecology N2 - A sediment core from Khatanga-12 Lake (Taimyr Peninsula, Krasnoyarsk krai) has been studied. The 131.5-cm-long core covers ca. 7100 years of sedimentation. Chironomid analysis, a qualitative reconstruction of the paleoenvironment in the region, and a quantitative reconstruction of variations of the mean July air temperature and in the water depth of the lake have been performed using Northern Russia chironomid-inferred mean July temperature models (Nazarova et al., 2008, 2011, 2015). Khatanga-12 Lake was formed during the Middle Holocene warming as a result of thermokarst processes. The development of the lake ecosystem at different stages of its development was influenced by climatic and cryolithogenic factors. The Middle Holocene warming, which occurred around 7100-6250 cal. years BP, activated thermokarst processes and resulted in the formation of the lake basin. Later, between 6250 and 4500 cal. years BP, a period of cooling took place, as is proved by chironomid analysis. The bottom sediments of the lake during this period were formed by erosion processes on the lake shores. The reconstructed conditions were close to the modern after 2500 cal. years BP. KW - Chironomidae KW - paleolimnology KW - Holocene KW - climate reconstructions KW - Russian Arctic region KW - Khatanga Y1 - 2017 U6 - https://doi.org/10.1134/S1995425517040114 SN - 1995-4255 SN - 1995-4263 VL - 10 SP - 363 EP - 369 PB - Pleiades Publ. CY - New York ER - TY - JOUR A1 - Surminski, Swenja A1 - Thieken, Annegret T1 - Promoting flood risk reduction BT - the role of insurance in Germany and England JF - Earth's Future N2 - Improving society's ability to prepare for, respond to and recover from flooding requires integrated, anticipatory flood risk management (FRM). However, most countries still focus their efforts on responding to flooding events if and when they occur rather than addressing their current and future vulnerability to flooding. Flood insurance is one mechanism that could promote a more ex ante approach to risk by supporting risk reduction activities. This paper uses an adapted version of Easton's System Theory to investigate the role of insurance for FRM in Germany and England. We introduce an anticipatory FRM framework, which allows flood insurance to be considered as part of a broader policy field. We analyze if and how flood insurance can catalyze a change toward a more anticipatory approach to FRM. In particular we consider insurance's role in influencing five key components of anticipatory FRM: risk knowledge, prevention through better planning, property‐level protection measures, structural protection and preparedness (for response). We find that in both countries FRM is still a reactive, event‐driven process, while anticipatory FRM remains underdeveloped. Collaboration between insurers and FRM decision‐makers has already been successful, for example in improving risk knowledge and awareness, while in other areas insurance acts as a disincentive for more risk reduction action. In both countries there is evidence that insurance can play a significant role in encouraging anticipatory FRM, but this remains underutilized. Effective collaboration between insurers and government should not be seen as a cost, but as an investment to secure future insurability through flood resilience. KW - flooding KW - insurance KW - governance KW - risk reduction Y1 - 2017 U6 - https://doi.org/10.1002/2017EF000587 SN - 2328-4277 VL - 5 SP - 979 EP - 1001 PB - Wiley CY - Hoboken ER - TY - JOUR A1 - Strauss, Jens A1 - Schirrmeister, Lutz A1 - Grosse, Guido A1 - Fortier, Daniel A1 - Hugelius, Gustaf A1 - Knoblauch, Christian A1 - Romanovsky, Vladimir E. A1 - Schadel, Christina A1 - von Deimling, Thomas Schneider A1 - Schuur, Edward A. G. A1 - Shmelev, Denis A1 - Ulrich, Mathias A1 - Veremeeva, Alexandra T1 - Deep Yedoma permafrost: A synthesis of depositional characteristics and carbon vulnerability JF - Earth science reviews : the international geological journal bridging the gap between research articles and textbooks N2 - Permafrost is a distinct feature of the terrestrial Arctic and is vulnerable to climate warming. Permafrost degrades in different ways, including deepening of a seasonally unfrozen surface and localized but rapid development of deep thaw features. Pleistocene ice-rich permafrost with syngenetic ice-wedges, termed Yedoma deposits, are widespread in Siberia, Alaska, and Yukon, Canada and may be especially prone to rapid-thaw processes. Freeze-locked organic matter in such deposits can be re-mobilized on short time-scales and contribute to a carbon-cycle climate feedback. Here we synthesize the characteristics and vulnerability of Yedoma deposits by synthesizing studies on the Yedoma origin and the associated organic carbon pool. We suggest that Yedoma deposits accumulated under periglacial weathering, transport, and deposition dynamics in non-glaciated regions during the late Pleistocene until the beginning of late glacial warming. The deposits formed due to a combination of aeolian, colluvial, nival, and alluvial deposition and simultaneous ground ice accumulation. We found up to 130 gigatons organic carbon in Yedoma, parts of which are well-preserved and available for fast decomposition after thaw. Based on incubation experiments, up to 10% of the Yedoma carbon is considered especially decomposable and may be released upon thaw. The substantial amount of ground ice in Yedoma makes it highly vulnerable to disturbances such as thermokarst and thermo-erosion processes. Mobilization of permafrost carbon is expected to increase under future climate warming. Our synthesis results underline the need of accounting for Yedoma carbon stocks in next generation Earth-System-Models for a more complete representation of the permafrost-carbon feedback. KW - Perennial frozen ground KW - Thermokarst KW - Arctic KW - Late Pleistocene KW - Greenhouse gas source KW - Climate feedback Y1 - 2017 U6 - https://doi.org/10.1016/j.earscirev.2017.07.007 SN - 0012-8252 SN - 1872-6828 VL - 172 SP - 75 EP - 86 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Stolle, Amelie A1 - Bernhardt, Anne A1 - Schwanghart, Wolfgang A1 - Hoelzmann, Philipp A1 - Adhikari, Basanta R. A1 - Fort, Monique A1 - Korup, Oliver T1 - Catastrophic valley fills record large Himalayan earthquakes, Pokhara, Nepal JF - Quaternary science reviews : the international multidisciplinary research and review journal KW - Catastrophic valley infill KW - Great Himalayan earthquakes KW - Radiocarbon age dating KW - Provenance analysis KW - Paleoseismology KW - Nepal Y1 - 2017 U6 - https://doi.org/10.1016/j.quascirev.2017.10.015 SN - 0277-3791 VL - 177 SP - 88 EP - 103 PB - Elsevier CY - Oxford ER - TY - JOUR A1 - Stinnesbeck, Wolfgang A1 - Becker, Julia A1 - Hering, Fabio A1 - Frey, Eberhard A1 - Gonzalez Gonzalez, Arturo A1 - Fohlmeister, Jens Bernd A1 - Stinnesbeck, Sarah A1 - Frank, Norbert A1 - Terrazas Mata, Alejandro A1 - Elena Benavente, Martha A1 - Aviles Olguin, Jeronimo A1 - Aceves Nunez, Eugenio A1 - Zell, Patrick A1 - Deininger, Michael T1 - The earliest settlers of Mesoamerica date back to the late Pleistocene JF - PLoS one N2 - Preceramic human skeletal remains preserved in submerged caves near Tulum in the Mexican state of Quintana Roo, Mexico, reveal conflicting results regarding C-14 dating. Here we use U-series techniques for dating a stalagmite overgrowing the pelvis of a human skeleton discovered in the submerged Chan Hol cave. The oldest closed system U/Th age comes from around 21 mm above the pelvis defining the terminus ante quem for the pelvis to 11311 +/- 370 y BP. However, the skeleton might be considerable older, probably as old as 13 ky BP as indicated by the speleothem stable isotope data. The Chan Hol individual confirms a late Pleistocene settling of Mesoamerica and represents one of the oldest human osteological remains in America. Y1 - 2017 U6 - https://doi.org/10.1371/journal.pone.0183345 SN - 1932-6203 VL - 12 PB - PLoS CY - San Fransisco ER - TY - JOUR A1 - Steinhöfel, Grit A1 - Breuer, Jörn A1 - von Blanckenburg, Friedhelm A1 - Horn, Ingo A1 - Sommer, Michael T1 - The dynamics of Si cycling during weathering in two small catchments in the Black Forest (Germany) traced by Si isotopes JF - Chemical geology : official journal of the European Association for Geochemistry N2 - Silicon stable isotopes have emerged as a powerful proxy to investigate weathering because Si uptake from solution by secondary minerals or by the vegetation causes significant shifts in the isotope composition. In this study, we determined the Si isotope compositions of the principle Si pools within two small catchments located on sandstone and paragneiss, respectively, in the temperate Black Forest (Germany). At both settings, clay formation is dominated by mineral transformation preserving largely the signature of parental minerals with delta Si-30 values of around -0.7%. Bulk soils rich in primary minerals are similar to bulk parental material with delta Si-30 values close to -0.4%. Topsoils are partly different because organic matter degradation has promoted intense weathering leading to delta Si-30 values as low as -1.0%. Water samples expose highly dynamic weathering processes in the soil zone: 1) after spring snowmelt, increased release of DOC and high water fluxes trigger clay mineral dissolution which leads to delta Si-30 values down to -0.7% and 2) in course of the summer, Si uptake by the vegetation and secondary mineral formation drives dissolved Si to typical positive delta Si-30 values up to 1.1%. Groundwater with delta Si-30 values of around 0.4% records steady processes in bedrock reflecting plagioclase weathering together with kaolinite precipitation. An isotope mass balance approach reveals incongruent weathering conditions where denudation of Si is largely driven by physical erosion. Erosion of phytoliths contributes 3 to 21% to the total Si export flux, which is in the same order as the dissolved Si flux. These results elucidate the Si dynamics during weathering on catchments underlain of sedimentary origin, prevailing on the Earth surface and provide therefore valuable information to interpret the isotope signature of large river systems. KW - Weathering KW - Sedimentary rocks KW - Biogeochemical Si cycle KW - Silicon isotopes KW - UV femtosecond laser ablation Y1 - 2017 U6 - https://doi.org/10.1016/j.chemgeo.2017.06.026 SN - 0009-2541 SN - 1878-5999 VL - 466 SP - 389 EP - 402 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Stanton, Richard A. A1 - Boone, Wesley W. A1 - Soto-Shoender, Jose A1 - Fletcher, Robert J. A1 - Blaum, Niels A1 - McCleery, Robert A. T1 - Shrub encroachment and vertebrate diversity BT - a global meta-analysis JF - Global ecology and biogeography : a journal of macroecology N2 - Aim: Across the planet, grass-dominated biomes are experiencing shrub encroachment driven by atmospheric CO2 enrichment and land-use change. By altering resource structure and availability, shrub encroachment may have important impacts on vertebrate communities. We sought to determine the magnitude and variability of these effects across climatic gradients, continents, and taxa, and to learn whether shrub thinning restores the structure of vertebrate communities. Location: Worldwide. Time period: Contemporary. Major taxa studied: Terrestrial vertebrates. Methods: We estimated relationships between percentage shrub cover and the structure of terrestrial vertebrate communities (species richness, Shannon diversity and community abundance) in experimentally thinned and unmanipulated shrub-encroached grass-dominated biomes using systematic review and meta-analyses of 43 studies published from 1978 to 2016. We modelled the effects of continent, biome, mean annual precipitation, net primary productivity and the normalized difference vegetation index (NDVI) on the relationship between shrub cover and vertebrate community structure. Results: Species richness, Shannon diversity and total abundance had no consistent relationship with shrub encroachment and experimental thinning did not reverse encroachment effects on vertebrate communities. However, some effects of shrub encroachment on vertebrate communities differed with net primary productivity, amongst vertebrate groups, and across continents. Encroachment had negative effects on vertebrate diversity at low net primary productivity. Mammalian and herpetofaunal diversity decreased with shrub encroachment. Shrub encroachment also had negative effects on species richness and total abundance in Africa but positive effects in North America. Main conclusions: Biodiversity conservation and mitigation efforts responding to shrub encroachment should focus on low-productivity locations, on mammals and herpetofauna, and in Africa. However, targeted research in neglected regions such as central Asia and India will be needed to fill important gaps in our knowledge of shrub encroachment effects on vertebrates. Additionally, our findings provide an impetus for determining the mechanisms associated with changes in vertebrate diversity and abundance in shrub-encroached grass-dominated biomes. KW - biodiversity KW - global change KW - grasslands KW - grazing KW - pastoral abandonment KW - savannas KW - shrub encroachment KW - shrub thinning KW - species richness KW - woody encroachment Y1 - 2017 U6 - https://doi.org/10.1111/geb.12675 SN - 1466-822X SN - 1466-8238 VL - 27 IS - 3 SP - 368 EP - 379 PB - Wiley CY - Hoboken ER - TY - JOUR A1 - Spinola, Diogo Noses A1 - Pi-Puig, Teresa A1 - Solleiro-Rebolledo, Elizabeth A1 - Egli, Markus A1 - Sudo, Masafumi A1 - Sedov, Sergey A1 - Kühn, Peter T1 - Origin of clay minerals in Early Eocene volcanic paleosols on King George Island, Maritime Antarctica JF - Scientific reports N2 - The paleoclimate during the Early Eocene in Maritime Antarctica is characterized by cool conditions without a pronounced dry season. Soils formed on volcanic material under such climate conditions in modern analogue environments are usually Andosols rich in nanocrystalline minerals without pedogenic smectite. The paleosols formed on volcanic material on King Georges Island are covered by basalts, dated by 6 new 40Ar/39Ar datings to 51-48 Ma, and are rich in smectite. A pedogenic origin of the smectites would suggest a semi-arid rather than a wet non-seasonal humid paleoclimate. To investigate the origin of the smectites in these paleosols we used X-ray diffraction and microscopic techniques. Minor mineralogical changes between the volcanic parent material and the paleosols and a homogenous distribution of smectites throughout the paleosol horizons indicate that these smectites were mainly inherited from the pyroclastic parent material, which was altered prior to surficial weathering. Nevertheless, the mineralogical properties, such as degree of crystallinity and octahedral site occupancy, of these smectites were modified during the ancient soil formation. Our findings highlight that trioctahedral smectites were a product of deuteric alteration of pyroclastic rocks and were progressively transformed to dioctahedral smectites during weathering in a soil environment on King George Island. Y1 - 2017 U6 - https://doi.org/10.1038/s41598-017-06617-x SN - 2045-2322 VL - 7 PB - Nature Publ. Group CY - London ER - TY - JOUR A1 - Spekkers, Matthieu A1 - Roezer, Viktor A1 - Thieken, Annegret A1 - ten Veldhuis, Marie-Claire A1 - Kreibich, Heidi T1 - A comparative survey of the impacts of extreme rainfall in two international case studies JF - Natural hazards and earth system sciences Y1 - 2017 U6 - https://doi.org/10.5194/nhess-17-1337-2017 SN - 1561-8633 VL - 17 SP - 1337 EP - 1355 PB - Copernicus CY - Göttingen ER - TY - JOUR A1 - Socquet, Anne A1 - Valdes, Jesus Pina A1 - Jara, Jorge A1 - Cotton, Fabrice A1 - Walpersdorf, Andrea A1 - Cotte, Nathalie A1 - von Specht, Sebastian A1 - Ortega-Culaciati, Francisco A1 - Carrizo, Daniel A1 - Norabuena, Edmundo T1 - An 8month slow slip event triggers progressive nucleation of the 2014 Chile megathrust JF - Geophysical research letters N2 - The mechanisms leading to large earthquakes are poorly understood and documented. Here we characterize the long-term precursory phase of the 1 April 2014 M(w)8.1 North Chile megathrust. We show that a group of coastal GPS stations accelerated westward 8months before the main shock, corresponding to a M(w)6.5 slow slip event on the subduction interface, 80% of which was aseismic. Concurrent interface foreshocks underwent a diminution of their radiation at high frequency, as shown by the temporal evolution of Fourier spectra and residuals with respect to ground motions predicted by recent subduction models. Such ground motions change suggests that in response to the slow sliding of the subduction interface, seismic ruptures are progressively becoming smoother and/or slower. The gradual propagation of seismic ruptures beyond seismic asperities into surrounding metastable areas could explain these observations and might be the precursory mechanism eventually leading to the main shock. KW - seismology KW - GPS KW - subduction KW - precursor Y1 - 2017 U6 - https://doi.org/10.1002/2017GL073023 SN - 0094-8276 SN - 1944-8007 VL - 44 SP - 4046 EP - 4053 PB - American Geophysical Union CY - Washington ER - TY - JOUR A1 - Sobolev, Stephan Vladimir A1 - Muldashev, Iskander A. T1 - Modeling Seismic Cycles of Great Megathrust Earthquakes Across the Scales With Focus at Postseismic Phase JF - Geochemistry, geophysics, geosystems Y1 - 2017 U6 - https://doi.org/10.1002/2017GC007230 SN - 1525-2027 VL - 18 SP - 4387 EP - 4408 PB - American Geophysical Union CY - Washington ER - TY - JOUR A1 - Smith, Taylor A1 - Bookhagen, Bodo A1 - Rheinwalt, Aljoscha T1 - identified with an automated snowmelt detection algorithm, 1987-2016 JF - The Cryosphere : TC ; an interactive open access journal of the European Geosciences Union N2 - High Mountain Asia (HMA) – encompassing the Tibetan Plateau and surrounding mountain ranges – is the primary water source for much of Asia, serving more than a billion downstream users. Many catchments receive the majority of their yearly water budget in the form of snow, which is poorly monitored by sparse in situ weather networks. Both the timing and volume of snowmelt play critical roles in downstream water provision, as many applications – such as agriculture, drinking-water generation, and hydropower – rely on consistent and predictable snowmelt runoff. Here, we examine passive microwave data across HMA with five sensors (SSMI, SSMIS, AMSR-E, AMSR2, and GPM) from 1987 to 2016 to track the timing of the snowmelt season – defined here as the time between maximum passive microwave signal separation and snow clearance. We validated our method against climate model surface temperatures, optical remote-sensing snow-cover data, and a manual control dataset (n = 2100, 3 variables at 25 locations over 28 years); our algorithm is generally accurate within 3–5 days. Using the algorithm-generated snowmelt dates, we examine the spatiotemporal patterns of the snowmelt season across HMA. The climatically short (29-year) time series, along with complex interannual snowfall variations, makes determining trends in snowmelt dates at a single point difficult. We instead identify trends in snowmelt timing by using hierarchical clustering of the passive microwave data to determine trends in self-similar regions. We make the following four key observations. (1) The end of the snowmelt season is trending almost universally earlier in HMA (negative trends). Changes in the end of the snowmelt season are generally between 2 and 8 days decade−1 over the 29-year study period (5–25 days total). The length of the snowmelt season is thus shrinking in many, though not all, regions of HMA. Some areas exhibit later peak signal separation (positive trends), but with generally smaller magnitudes than trends in snowmelt end. (2) Areas with long snowmelt periods, such as the Tibetan Plateau, show the strongest compression of the snowmelt season (negative trends). These trends are apparent regardless of the time period over which the regression is performed. (3) While trends averaged over 3 decades indicate generally earlier snowmelt seasons, data from the last 14 years (2002–2016) exhibit positive trends in many regions, such as parts of the Pamir and Kunlun Shan. Due to the short nature of the time series, it is not clear whether this change is a reversal of a long-term trend or simply interannual variability. (4) Some regions with stable or growing glaciers – such as the Karakoram and Kunlun Shan – see slightly later snowmelt seasons and longer snowmelt periods. It is likely that changes in the snowmelt regime of HMA account for some of the observed heterogeneity in glacier response to climate change. While the decadal increases in regional temperature have in general led to earlier and shortened melt seasons, changes in HMA's cryosphere have been spatially and temporally heterogeneous. Y1 - 2017 U6 - https://doi.org/10.5194/tc-11-2329-2017 SN - 1994-0416 SN - 1994-0424 VL - 11 SP - 2329 EP - 2343 PB - Copernicus CY - Göttingen ER - TY - JOUR A1 - Smith, Taylor A1 - Bookhagen, Bodo A1 - Rheinwalt, Aljoscha T1 - Spatiotemporal patterns of High Mountain Asia's snowmelt season identified with an automated snowmelt detection algorithm, 1987-2016 JF - The Cryosphere : TC ; an interactive open access journal of the European Geosciences Union N2 - High Mountain Asia (HMA) - encompassing the Tibetan Plateau and surrounding mountain ranges - is the primary water source for much of Asia, serving more than a billion downstream users. Many catchments receive the majority of their yearly water budget in the form of snow, which is poorly monitored by sparse in situ weather networks. Both the timing and volume of snowmelt play critical roles in downstream water provision, as many applications - such as agriculture, drinking-water generation, and hydropower - rely on consistent and predictable snowmelt runoff. Here, we examine passive microwave data across HMA with five sensors (SSMI, SSMIS, AMSR-E, AMSR2, and GPM) from 1987 to 2016 to track the timing of the snowmelt season - defined here as the time between maximum passive microwave signal separation and snow clearance. We validated our method against climate model surface temperatures, optical remote-sensing snow-cover data, and a manual control dataset (n = 2100, 3 variables at 25 locations over 28 years); our algorithm is generally accurate within 3-5 days. Using the algorithm-generated snowmelt dates, we examine the spatiotemporal patterns of the snowmelt season across HMA. The climatically short (29-year) time series, along with complex interannual snowfall variations, makes determining trends in snowmelt dates at a single point difficult. We instead identify trends in snowmelt timing by using hierarchical clustering of the passive microwave data to determine trends in self-similar regions. We make the following four key observations. (1) The end of the snowmelt season is trending almost universally earlier in HMA (negative trends). Changes in the end of the snowmelt season are generally between 2 and 8 days decade 1 over the 29-year study period (5-25 days total). The length of the snowmelt season is thus shrinking in many, though not all, regions of HMA. Some areas exhibit later peak signal separation (positive trends), but with generally smaller magnitudes than trends in snowmelt end. (2) Areas with long snowmelt periods, such as the Tibetan Plateau, show the strongest compression of the snowmelt season (negative trends). These trends are apparent regardless of the time period over which the regression is performed. (3) While trends averaged over 3 decades indicate generally earlier snowmelt seasons, data from the last 14 years (2002-2016) exhibit positive trends in many regions, such as parts of the Pamir and Kunlun Shan. Due to the short nature of the time series, it is not clear whether this change is a reversal of a long-term trend or simply interannual variability. (4) Some regions with stable or growing glaciers - such as the Karakoram and Kunlun Shan - see slightly later snowmelt seasons and longer snowmelt periods. It is likely that changes in the snowmelt regime of HMA account for some of the observed heterogeneity in glacier response to climate change. While the decadal increases in regional temperature have in general led to earlier and shortened melt seasons, changes in HMA's cryosphere have been spatially and temporally heterogeneous. Y1 - 2017 U6 - https://doi.org/10.5194/tc-11-2329-2017 SN - 1994-0416 SN - 1994-0424 VL - 11 SP - 2329 EP - 2343 ER - TY - JOUR A1 - Sirbescu, Mona-Liza C. A1 - Schmidt, Christian A1 - Veksler, Ilya V. A1 - Whittington, Alan G. A1 - Wilke, Max T1 - Experimental crystallization of undercooled felsic liquids BT - generation of pegmatitic texture JF - Journal of petrology N2 - The crystallization kinetics of silicate liquids were studied experimentally in the system haplogranite-B-Li-H2O, at variable degrees of undercooling and variable water concentration. We investigated the kinetics of nucleation and crystallization of unseeded synthetic hydrous haplogranite with 1 wt % Li2O + 2 center dot 3 wt % B2O3 added (composition C1) and 2 wt % Li2O + 4 center dot 6 wt % B2O3 added (composition C2). Compositions C1 and C2 are simplified representative bulk compositions of Li-rich pegmatites and their highly differentiated cores, respectively. Starting water contents varied between 3 and 9 wt %. With few exceptions, the system remained water-undersaturated. About 86 isothermal runs of 1-60 days duration, grouped in 25 time series of constant temperature and initial H2O content, were carried out at temperatures from 400 to 700A degrees C at 300 MPa, corresponding to variable degrees of undercooling between the liquidus and glass transition. Viscosity measurements indicate that the glass transition for both compositions is below 400A degrees C for 3 wt % water and below 300A degrees C for 6 center dot 5 wt % water. The melts remained virtually crystal free at 400A degrees C, about 100A degrees C and 120A degrees C above the glass transition for compositions C1 and C2, respectively, in experiments up to 30 days long. This result is consistent with the existence of low-temperature, undercooled melts in the crust. At lower values of undercooling the runs crystallized partially, up to about 70% volume fraction. Undercooling and the amount of water are the main factors controlling nucleation and growth rates, and therefore textures. Minerals nucleate and grow sequentially according to mineral-specific nucleation delays. The mineral assemblage started with Li-Al stuffed quartz (in C1) and virgilite (in C2), solid-solutions between quartz and gamma-spodumene. The quartz-like phases were typically followed by spherulitic alkali feldspar-quartz intergrowths, euhedral petalite, and fine-grained muscovite. Nearly pure quartz formed as rims and replacement of metastable virgilite and stuffed quartz, in particular at the boron- and water-rich crystallization front of large feldspar or petalite. With the exception of muscovite, all minerals nucleated heterogeneously, on the capsule wall or on pre-existing minerals, and grew inwards, towards the capsule center. Experimental textures resembled the textures of zoned pegmatites, including skeletal, graphic, unidirectional, radiating, spherulitic, massive, and replacement textures. In some cases, when fluid saturation was reached, miarolitic cavities developed containing euhedral crystals. Although unidirectional growth rates appeared to slow down in time, volumetric rates for stable graphic alkali-feldspar quartz intergrowths and petalite remained constant for up to 60 days and similar to 70% crystallization. Metastable stuffed quartz and virgilite diminished in their growth rates in runs of 30 days or longer, were resorbed in the melt, and were partially replaced by second-generation quartz. Unobstructed, self-sustained crystal growth in conditions of very low nucleation density appears to be the dominant mechanism to form giant pegmatitic crystals, although experimental growth rates are much slower than predicted in nature based on conductive-cooling models. KW - experimental petrology KW - lithium pegmatites KW - igneous texture KW - viscosity KW - crystal nucleation KW - crystal growth rate Y1 - 2017 U6 - https://doi.org/10.1093/petrology/egx027 SN - 0022-3530 SN - 1460-2415 VL - 58 IS - 3 SP - 539 EP - 568 PB - Oxford Univ. Press CY - Oxford ER - TY - JOUR A1 - Sippel, Judith A1 - Meessen, Christian A1 - Cacace, Mauro A1 - Mechie, James A1 - Fishwick, Stewart A1 - Heine, Christian A1 - Scheck-Wenderoth, Magdalena A1 - Strecker, Manfred T1 - The Kenya rift revisited BT - insights into lithospheric strength through data-driven 3-D gravity and thermal modelling JF - Solid earth N2 - We present three-dimensional (3-D) models that describe the present-day thermal and rheological state of the lithosphere of the greater Kenya rift region aiming at a better understanding of the rift evolution, with a particular focus on plume-lithosphere interactions. The key methodology applied is the 3-D integration of diverse geological and geophysical observations using gravity modelling. Accordingly, the resulting lithospheric-scale 3-D density model is consistent with (i) reviewed descriptions of lithological variations in the sedimentary and volcanic cover, (ii) known trends in crust and mantle seismic velocities as revealed by seismic and seismological data and (iii) the observed gravity field. This data-based model is the first to image a 3-D density configuration of the crystalline crust for the entire region of Kenya and northern Tanzania. An upper and a basal crustal layer are differentiated, each composed of several domains of different average densities. We interpret these domains to trace back to the Precambrian terrane amalgamation associated with the East African Orogeny and to magmatic processes during Mesozoic and Cenozoic rifting phases. In combination with seismic velocities, the densities of these crustal domains indicate compositional differences. The derived lithological trends have been used to parameterise steady-state thermal and rheological models. These models indicate that crustal and mantle temperatures decrease from the Kenya rift in the west to eastern Kenya, while the integrated strength of the lithosphere increases. Thereby, the detailed strength configuration appears strongly controlled by the complex inherited crustal structure, which may have been decisive for the onset, localisation and propagation of rifting. Y1 - 2017 U6 - https://doi.org/10.5194/se-8-45-2017 SN - 1869-9510 SN - 1869-9529 VL - 8 SP - 45 EP - 81 PB - Copernicus CY - Göttingen ER - TY - JOUR A1 - Sier, Mark J. A1 - Langereis, Cor G. A1 - Dupont-Nivet, Guillaume A1 - Feibel, Craig S. A1 - Joordens, Josephine C. A. A1 - van der Lubbe, Jeroen Fiji. A1 - Beck, Catherine C. A1 - Olago, Daniel A1 - Cohen, Andrew T1 - The top of the Olduvai Subchron in a high-resolution magnetostratigraphy from the West Turkana core WTK13, hominin sites and Paleolakes Drilling Project (HSPDP) JF - Quaternary geochronology : the international research and review journal on advances in quaternary dating techniques N2 - One of the major challenges in understanding the evolution of our own species is identifying the role climate change has played in the evolution of hominin species. To clarify the influence of climate, we need long and continuous high-resolution paleoclimate records, preferably obtained from hominin-bearing sediments, that are well-dated by tephro- and magnetostratigraphy and other methods. This is hindered, however, by the fact that fossil-bearing outcrop sediments are often discontinuous, and subject to weathering, which may lead to oxidation and remagnetization. To obtain fresh, unweathered sediments, the Hominin Sites and Paleolakes Drilling Project (HSPDP) collected a ∼216-meter core (WTK13) in 2013 from Early Pleistocene Paleolake Lorenyang deposits in the western Turkana Basin (Kenya). Here, we present the magnetostratigraphy of the WTK13 core, providing a first age model for upcoming HSPDP paleoclimate and paleoenvrionmental studies on the core sediments. Rock magnetic analyses reveal the presence of iron sulfides carrying the remanent magnetizations. To recover polarity orientation from the near-equatorial WTK13 core drilled at 5°N, we developed and successfully applied two independent drill-core reorientation methods taking advantage of (1) the sedimentary fabric as expressed in the Anisotropy of Magnetic Susceptibility (AMS) and (2) the occurrence of a viscous component oriented in the present day field. The reoriented directions reveal a normal to reversed polarity reversal identified as the top of the Olduvai Subchron. From this excellent record, we find no evidence for the ‘Vrica Subchron’ previously reported in the area. We suggest that outcrop-based interpretations supporting the presence of the Vrica Subchron have been affected by the oxidation of iron sulfides initially present in the sediments -as evident in the core record- and by subsequent remagnetization. We discuss the implications of the observed geomagnetic record for human evolution studies. KW - Paleolake Lorenyang KW - Magnetostratigraphy KW - Olduvai Subchron KW - Vrica Subchron KW - Drill-core reorientation KW - ICDP KW - Paleoclimate KW - Hominin evolution Y1 - 2017 U6 - https://doi.org/10.1016/j.quageo.2017.08.004 SN - 1871-1014 SN - 1878-0350 VL - 42 SP - 117 EP - 129 PB - Elsevier CY - Oxford ER - TY - JOUR A1 - Sieg, Tobias A1 - Vogel, Kristin A1 - Merz, Bruno A1 - Kreibich, Heidi T1 - Tree-based flood damage modeling of companies: Damage processes and model performance JF - Water resources research N2 - Reliable flood risk analyses, including the estimation of damage, are an important prerequisite for efficient risk management. However, not much is known about flood damage processes affecting companies. Thus, we conduct a flood damage assessment of companies in Germany with regard to two aspects. First, we identify relevant damage-influencing variables. Second, we assess the prediction performance of the developed damage models with respect to the gain by using an increasing amount of training data and a sector-specific evaluation of the data. Random forests are trained with data from two postevent surveys after flood events occurring in the years 2002 and 2013. For a sector-specific consideration, the data set is split into four subsets corresponding to the manufacturing, commercial, financial, and service sectors. Further, separate models are derived for three different company assets: buildings, equipment, and goods and stock. Calculated variable importance values reveal different variable sets relevant for the damage estimation, indicating significant differences in the damage process for various company sectors and assets. With an increasing number of data used to build the models, prediction errors decrease. Yet the effect is rather small and seems to saturate for a data set size of several hundred observations. In contrast, the prediction improvement achieved by a sector-specific consideration is more distinct, especially for damage to equipment and goods and stock. Consequently, sector-specific data acquisition and a consideration of sector-specific company characteristics in future flood damage assessments is expected to improve the model performance more than a mere increase in data. Y1 - 2017 U6 - https://doi.org/10.1002/2017WR020784 SN - 0043-1397 SN - 1944-7973 VL - 53 SP - 6050 EP - 6068 PB - American Geophysical Union CY - Washington ER - TY - JOUR A1 - Siddiqui, Tarique Adnan A1 - Stolle, Claudia A1 - Lühr, Hermann T1 - Longitude-dependent lunar tidal modulation of the equatorial electrojet during stratospheric sudden warmings JF - Journal of geophysical research : Space physics N2 - The effects of coupling between different layers of the atmosphere during Stratospheric Sudden Warming (SSW) events have been studied quite extensively in the past fewyears, and in this context large lunitidal enhancements in the equatorial ionosphere have also been widely discussed. In this study we report about the longitudinal variabilities in lunitidal enhancement in the equatorial electrojet (EEJ) during SSWs through ground and space observations in the Peruvian and Indian sectors. We observe that the amplification of lunitidal oscillations in EEJ is significantly larger over the Peruvian sector in comparison to the Indian sector. We further compare the lunitidal oscillations in both the sectors during the 2005-2006 and 2008-2009 major SSW events and during a non-SSW winter of 2006-2007. It is found that the lunitidal amplitude in EEJ over the Peruvian sector showed similar enhancements during both the major SSWs, but the enhancements were notably different in the Indian sector. Independent from SSW events, we have also performed a climatological analysis of the lunar modulation of the EEJ during December solstice over both the sectors by using 10years of CHAMP magnetic measurements and found larger lunitidal amplitudes over the Peruvian sector confirming the results from ground magnetometer observations. We have also analyzed the semidiurnal lunar tidal amplitude in neutral temperature measurements from Sounding of the Atmosphere using Broadband Emission Radiometry (SABER) at 110km and found lesser longitudinal variability than the lunitidal amplitude in EEJ. Our results suggest that the longitudinal variabilities in lunitidal modulation of the EEJ during SSWs could be related to electrodynamics in the E region dynamo. KW - SSW KW - vertical coupling KW - equatorial electrojet KW - lunar tide of EEJ Y1 - 2017 U6 - https://doi.org/10.1002/2016JA023609 SN - 2169-9380 SN - 2169-9402 VL - 122 IS - 3 SP - 3760 EP - 3776 PB - American Geophysical Union CY - Washington ER - TY - JOUR A1 - Seiler, Claudia A1 - van Velzen, Ellen A1 - Neu, Thomas R. A1 - Gaedke, Ursula A1 - Berendonk, Thomas U. A1 - Weitere, Markus T1 - Grazing resistance of bacterial biofilms: a matter of predators’ feeding trait JF - FEMS microbiology ecology N2 - Biofilm formation in bacteria is considered to be one strategy to avoid protozoan grazing. However, this assumption is largely based on experiments with suspension-feeding protozoans. Here we test the hypothesis that grazing resistance depends on both the grazers’ feeding trait and the bacterial phenotype, rather than being a general characteristic of bacterial biofilms. We combined batch experiments with mathematical modelling, considering the bacterium Pseudomonas putida and either a suspension-feeding (i.e. the ciliate Paramecium tetraurelia) or a surface-feeding grazer (i.e. the amoeba Acanthamoeba castellanii). We find that both plankton and biofilm phenotypes were consumed, when exposed to their specialised grazer, whereas the other phenotype remained grazing-resistant. This was consistently shown in two experiments (starting with either only planktonic bacteria or with additional pre-grown biofilms) and matches model predictions. In the experiments, the plankton feeder strongly stimulated the biofilm biomass. This stimulation of the resistant prey phenotype was not predicted by the model and it was not observed for the biofilm feeders, suggesting the existence of additional mechanisms that stimulate biofilm formation besides selective feeding. Overall, our results confirm our hypothesis that grazing resistance is a matter of the grazers’ trait (i.e. feeding type) rather than a biofilm-specific property. KW - protozoa KW - biofilm KW - plankton KW - predator-prey model KW - grazing defence KW - feeding trait Y1 - 2017 U6 - https://doi.org/10.1093/femsec/fix112 SN - 0168-6496 SN - 1574-6941 VL - 93 PB - Oxford Univ. Press CY - Oxford ER - TY - JOUR A1 - Seibert, Mathias A1 - Merz, Bruno A1 - Apel, Heiko T1 - Seasonal forecasting of hydrological drought in the Limpopo Basin BT - a comparison of statistical methods JF - Hydrology and earth system sciences : HESS N2 - The Limpopo Basin in southern Africa is prone to droughts which affect the livelihood of millions of people in South Africa, Botswana, Zimbabwe and Mozambique. Seasonal drought early warning is thus vital for the whole region. In this study, the predictability of hydrological droughts during the main runoff period from December to May is assessed using statistical approaches. Three methods (multiple linear models, artificial neural networks, random forest regression trees) are compared in terms of their ability to forecast streamflow with up to 12 months of lead time. The following four main findings result from the study. 1. There are stations in the basin at which standardised streamflow is predictable with lead times up to 12 months. The results show high inter-station differences of forecast skill but reach a coefficient of determination as high as 0.73 (cross validated). 2. A large range of potential predictors is considered in this study, comprising well-established climate indices, customised teleconnection indices derived from sea surface temperatures and antecedent streamflow as a proxy of catchment conditions. El Nino and customised indices, representing sea surface temperature in the Atlantic and Indian oceans, prove to be important teleconnection predictors for the region. Antecedent streamflow is a strong predictor in small catchments (with median 42% explained variance), whereas teleconnections exert a stronger influence in large catchments. 3. Multiple linear models show the best forecast skill in this study and the greatest robustness compared to artificial neural networks and random forest regression trees, despite their capabilities to represent nonlinear relationships. 4. Employed in early warning, the models can be used to forecast a specific drought level. Even if the coefficient of determination is low, the forecast models have a skill better than a climatological forecast, which is shown by analysis of receiver operating characteristics (ROCs). Seasonal statistical forecasts in the Limpopo show promising results, and thus it is recommended to employ them as complementary to existing forecasts in order to strengthen preparedness for droughts. Y1 - 2017 U6 - https://doi.org/10.5194/hess-21-1611-2017 SN - 1027-5606 SN - 1607-7938 VL - 21 SP - 1611 EP - 1629 PB - Copernicus CY - Göttingen ER - TY - JOUR A1 - Schwanghart, Wolfgang A1 - Scherler, Dirk T1 - Bumps in river profiles: uncertainty assessment and smoothing using quantile regression techniques JF - Earth surface dynamics N2 - The analysis of longitudinal river profiles is an important tool for studying landscape evolution. However, characterizing river profiles based on digital elevation models (DEMs) suffers from errors and artifacts that particularly prevail along valley bottoms. The aim of this study is to characterize uncertainties that arise from the analysis of river profiles derived from different, near-globally available DEMs. We devised new algorithms quantile carving and the CRS algorithm - that rely on quantile regression to enable hydrological correction and the uncertainty quantification of river profiles. We find that globally available DEMs commonly overestimate river elevations in steep topography. The distributions of elevation errors become increasingly wider and right skewed if adjacent hillslope gradients are steep. Our analysis indicates that the AW3D DEM has the highest precision and lowest bias for the analysis of river profiles in mountainous topography. The new 12m resolution TanDEM-X DEM has a very low precision, most likely due to the combined effect of steep valley walls and the presence of water surfaces in valley bottoms. Compared to the conventional approaches of carving and filling, we find that our new approach is able to reduce the elevation bias and errors in longitudinal river profiles. Y1 - 2017 U6 - https://doi.org/10.5194/esurf-5-821-2017 SN - 2196-6311 SN - 2196-632X VL - 5 SP - 821 EP - 839 PB - Copernicus CY - Göttingen ER - TY - JOUR A1 - Schrön, Martin A1 - Köhli, Markus A1 - Scheiffele, Lena A1 - Iwema, Joost A1 - Bogena, Heye R. A1 - Lv, Ling A1 - Martini, Edoardo A1 - Baroni, Gabriele A1 - Rosolem, Rafael A1 - Weimar, Jannis A1 - Mai, Juliane A1 - Cuntz, Matthias A1 - Rebmann, Corinna A1 - Oswald, Sascha A1 - Dietrich, Peter A1 - Schmidt, Ulrich A1 - Zacharias, Steffen T1 - Improving calibration and validation of cosmic-ray neutron sensors in the light of spatial sensitivity JF - Hydrology and earth system sciences : HESS N2 - In the last few years the method of cosmic-ray neutron sensing (CRNS) has gained popularity among hydrologists, physicists, and land-surface modelers. The sensor provides continuous soil moisture data, averaged over several hectares and tens of decimeters in depth. However, the signal still may contain unidentified features of hydrological processes, and many calibration datasets are often required in order to find reliable relations between neutron intensity and water dynamics. Recent insights into environmental neutrons accurately described the spatial sensitivity of the sensor and thus allowed one to quantify the contribution of individual sample locations to the CRNS signal. Consequently, data points of calibration and validation datasets are suggested to be averaged using a more physically based weighting approach. In this work, a revised sensitivity function is used to calculate weighted averages of point data. The function is different from the simple exponential convention by the extraordinary sensitivity to the first few meters around the probe, and by dependencies on air pressure, air humidity, soil moisture, and vegetation. The approach is extensively tested at six distinct monitoring sites: two sites with multiple calibration datasets and four sites with continuous time series datasets. In all cases, the revised averaging method improved the performance of the CRNS products. The revised approach further helped to reveal hidden hydrological processes which otherwise remained unexplained in the data or were lost in the process of overcalibration. The presented weighting approach increases the overall accuracy of CRNS products and will have an impact on all their applications in agriculture, hydrology, and modeling. Y1 - 2017 U6 - https://doi.org/10.5194/hess-21-5009-2017 SN - 1027-5606 SN - 1607-7938 VL - 21 SP - 5009 EP - 5030 PB - Copernicus CY - Göttingen ER - TY - JOUR A1 - Schmidt, Katja A1 - Walz, Ariane A1 - Martin-Lopez, Berta A1 - Sachse, Rene T1 - Testing socio-cultural valuation methods of ecosystem services to explain land use preferences JF - Ecosystem Services : Science, Policy and Practice N2 - Socio-cultural valuation still emerges as a methodological field in ecosystem service (ES) research and until now lacks consistent formalisation and balanced application in ES assessments. In this study, we examine the explanatory value of ES values for land use preferences. We use 563 responses to a survey about the Pentland Hills regional park in Scotland. Specifically, we aim to (1) identify clusters of land use preferences by using a novel visualisation tool, (2) test if socio-cultural values of ESs or (3) user characteristics are linked with land use preferences, and (4) determine whether both socio-cultural values of ESs and user characteristics can predict land use preferences. Our results suggest that there are five groups of people with different land use preferences, ranging from forest and nature enthusiasts to traditionalists, multi-functionalists and recreation seekers. Rating and weighting of ESs and user characteristics were associated with different clusters. Neither socio-cultural values nor user characteristics were suitable predictors for land use preferences. While several studies have explored land use preferences by identifying socio-cultural values in the past, our findings imply that in this case study ES values inform about general perceptions but do not replace the assessment of land use preferences. (C) 2017 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license. KW - Non-monetary valuation KW - Values KW - Visitors KW - Landscape visualisation KW - Visualisation tool Y1 - 2017 U6 - https://doi.org/10.1016/j.ecoser.2017.07.001 SN - 2212-0416 VL - 26 SP - 270 EP - 288 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Schernthanner, Harald A1 - Asche, Hartmut A1 - Gonschorek, Julia A1 - Scheele, Lasse T1 - Spatial Modeling and Geovisualization of Rental Prices for Real Estate portals JF - International journal of agricultural and environmental information systems : an official publication of the Information Resources Management Association KW - Geoinformation Science KW - Geostatistics KW - Geo-Visualisation KW - Real Estate Portal KW - Rental Prize KW - Spatial Modeling Y1 - 2017 U6 - https://doi.org/10.4018/IJAEIS.2017040106 SN - 1947-3192 SN - 1947-3206 VL - 8 SP - 78 EP - 91 PB - IGI Global CY - Hershey ER - TY - JOUR A1 - Schattan, Paul A1 - Baroni, Gabriele A1 - Oswald, Sascha A1 - Schoeber, Johannes A1 - Fey, Christine A1 - Kormann, Christoph A1 - Huttenlau, Matthias A1 - Achleitner, Stefan T1 - Continuous monitoring of snowpack dynamics in alpine terrain by aboveground neutron sensing JF - Water resources research N2 - The characteristics of an aboveground cosmic-ray neutron sensor (CRNS) are evaluated for monitoring a mountain snowpack in the Austrian Alps from March 2014 to June 2016. Neutron counts were compared to continuous point-scale snow depth (SD) and snow-water-equivalent (SWE) measurements from an automatic weather station with a maximum SWE of 600 mm (April 2014). Several spatially distributed Terrestrial Laser Scanning (TLS)-based SD and SWE maps were additionally used. A strong nonlinear correlation is found for both SD and SWE. The representative footprint of the CRNS is in the range of 230-270 m. In contrast to previous studies suggesting signal saturation at around 100 mm of SWE, no complete signal saturation was observed. These results imply that CRNS could be transferred into an unprecedented method for continuous detection of spatially averaged SD and SWE for alpine snowpacks, though with sensitivity decreasing with increasing SWE. While initially different functions were found for accumulation and melting season conditions, this could be resolved by accounting for a limited measurement depth. This depth limit is in the range of 200 mm of SWE for dense snowpacks with high liquid water contents and associated snow density values around 450 kg m(-3) and above. In contrast to prior studies with shallow snowpacks, interannual transferability of the results is very high regardless of presnowfall soil moisture conditions. This underlines the unexpectedly high potential of CRNS to close the gap between point-scale measurements, hydrological models, and remote sensing of the cryosphere in alpine terrain. KW - cosmic-ray neutron sensing KW - snow hydrology KW - continuous snowpack monitoring KW - alpine environment Y1 - 2017 U6 - https://doi.org/10.1002/2016WR020234 SN - 0043-1397 SN - 1944-7973 VL - 53 SP - 3615 EP - 3634 PB - American Geophysical Union CY - Washington ER - TY - JOUR A1 - Sahle, Christoph J. A1 - Niskanen, Johannes A1 - Schmidt, Christian A1 - Stefanski, Johannes A1 - Gilmore, Keith A1 - Forov, Yury A1 - Jahn, Sandro A1 - Wilke, Max A1 - Sternemann, Christian T1 - Cation Hydration in Supercritical NaOH and HCl Aqueous Solutions JF - The journal of physical chemistry : B, Condensed matter, materials, surfaces, interfaces & biophysical chemistry N2 - We present a study of the local atomic environment of the oxygen atoms in the aqueous solutions of NaOH and HCl under simultaneous high-temperature and high-pressure conditions. Experimental nonresonant X-ray Raman scattering core-level spectra at the oxygen K-edge show systematic changes as a function of temperature and pressure. These systematic changes are distinct for the two different solutes and are described well by calculations within the Bethe- Salpeter formalism for snapshots from ab initio molecular dynamics simulations. The agreement between experimental and simulation results allows us to use the computations for a detailed fingerprinting analysis in an effort to elucidate the local atomic structure and hydrogen-bonding topology in these relevant solutions. We observe that both electrolytes, especially NaOH, enhance hydrogen bonding and tetrahedrality in the water structure at supercritical conditions, in particular in the vicinity of the hydration shells. This effect is accompanied with the association of the HCl and NaOH molecules at elevated temperatures. Y1 - 2017 U6 - https://doi.org/10.1021/acs.jpcb.7b09688 SN - 1520-6106 VL - 121 SP - 11383 EP - 11389 PB - American Chemical Society CY - Washington ER - TY - JOUR A1 - Ryberg, Trond A1 - Braeuer, Benjamin A1 - Weber, Michael T1 - Upper mantle structure at Walvis Ridge from P-n tomography JF - Tectonophysics : international journal of geotectonics and the geology and physics of the interior of the earth N2 - Passive continental margins offer the unique opportunity to study the processes involved in continental extension and break-up. Within the LISPWAL (Llthospheric Structure of the Namibian continental Passive margin at the intersection with the Walvis Ridge from amphibious seismic investigations) project, combined on- and offshore seismic experiments were designed to characterize the Southern African passive margin at the Walvis Ridge in northern Namibia. In addition to extensive analysis of the crustal structures, we carried out seismic investigations targeting the velocity structure of the upper mantle in the landfall region of the Walvis Ridge with the Namibian coast. Upper mantle P-n travel time tomography from controlled source, amphibious seismic data was used to investigate the sub-Moho upper mantle seismic velocity. We succeeded in imaging upper mantle structures potentially associated with continental break-up and/or the Tristan da Cunha hotspot track. We found mostly coast-parallel sub-Moho velocity anomalies, interpreted as structures which were created during Gondwana break-up. (C)2016 Published by Elsevier B.V. KW - Seismic investigations KW - P-n tomography KW - passive continental margin KW - Gondwana break-up Y1 - 2017 U6 - https://doi.org/10.1016/j.tecto.2016.08.009 SN - 0040-1951 SN - 1879-3266 VL - 716 SP - 121 EP - 129 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Rudolph-Mohr, Nicole A1 - Toetzke, Christian A1 - Kardjilov, Nikolay A1 - Oswald, Sascha T1 - Mapping water, oxygen, and pH dynamics in the rhizosphere of young maize roots JF - Journal of plant nutrition and soil science = Zeitschrift für Pflanzenernährung und Bodenkunde N2 - Rhizosphere processes are highly dynamic in time and space and strongly depend on each other. Key factors influencing pH changes in the rhizosphere are root exudation, respiration, and nutrient supply, which are influenced by soil water content levels. In this study, we measured the real-time distribution of soil water, pH changes, and oxygen distribution in the rhizosphere of young maize plants using a recently developed imaging approach. Neutron radiography was used to capture the root system and soil water distribution, while fluorescence imaging was employed to map soil pH and soil oxygen changes. Germinated seeds of maize (Zea mays L.) were planted in glass rhizotrons equipped with pH and oxygen-sensitive sensor foils. After 20 d, the rhizotrons were wetted from the bottom and time-lapsed images via fluorescence and neutron imaging were taken during the subsequent day and night cycles for 5 d. We found higher water content and stronger acidification in the first 0.5 mm from the root surface compared to the bulk soil, which could be a consequence of root exudation. While lateral roots only slightly acidified their rhizosphere, crown roots induced stronger acidification of up to 1 pH unit. We observed changing oxygen patterns at different soil moisture conditions and increasing towards lateral as well as crown roots while extending laterally with ongoing water logging. Our work indicates that plants alter the rhizosphere pH and oxygen also depending on root type, which may indirectly arise also from differences in age and water content changes. The results presented here were possible only by combining different imaging techniques to examine profiles at the root-soil interface in a comprehensive way during wetting and drying. KW - crown roots KW - imaging KW - optical sensors KW - root exudation KW - root respiration Y1 - 2017 U6 - https://doi.org/10.1002/jpln.201600120 SN - 1436-8730 SN - 1522-2624 VL - 180 SP - 336 EP - 346 PB - Wiley-VCH CY - Weinheim ER - TY - JOUR A1 - Rubey, Michael A1 - Brune, Sascha A1 - Heine, Christian A1 - Davies, D. Rhodri A1 - Williams, Simon E. A1 - Müller, R. Dietmar T1 - role of subducted slabs JF - Solid earth Y1 - 2017 U6 - https://doi.org/10.5194/se-8-899-2017 SN - 1869-9510 SN - 1869-9529 VL - 8 SP - 899 EP - 919 PB - Copernicus CY - Göttingen ER - TY - JOUR A1 - Rosenwinkel, Swenja A1 - Landgraf, Angela A1 - Schwanghart, Wolfgang A1 - Volkmer, Friedrich A1 - Dzhumabaeva, Atyrgul A1 - Merchel, Silke A1 - Rugel, Georg A1 - Preusser, Frank A1 - Korup, Oliver T1 - Late Pleistocene outburst floods from Issyk Kul, Kyrgyzstan? JF - Earth surface processes and landforms : the journal of the British Geomorphological Research Group KW - outburst flood KW - lake-level changes KW - Issyk Kul KW - Kyrgyzstan KW - cosmogenic nuclides Y1 - 2017 U6 - https://doi.org/10.1002/esp.4109 SN - 0197-9337 SN - 1096-9837 VL - 42 SP - 1535 EP - 1548 PB - Wiley CY - Hoboken ER - TY - JOUR A1 - Rodriguez-Zuluaga, Juan A1 - Stolle, Claudia A1 - Park, J. T1 - On the direction of the Poynting flux associated with equatorial plasma depletions as derived from Swarm JF - Geophysical research letters N2 - Magnetic and electric field observations from the European Space Agency Swarm mission are used to report the direction of electromagnetic energy flux associated with equatorial plasma depletions. Contrary to expectations, the observations suggest a general interhemispheric Poynting flux rather than concurrent flows at both hemispheres toward or away from the equator. Of high interest is a particular behavior noticed over the region with the largest variation in the magnetic declination. This is a Poynting flux flowing mainly into the southern magnetic hemisphere about between 60 degrees W and 30 degrees E and into the northern magnetic hemisphere between 110 degrees W and 60 degrees W. The abrupt change in the flow direction at 60 degrees W is suggested to be caused by an asymmetry between the hemispheres on the ionospheric conductivity, likely due to the influence of thermospheric winds and the presence of the South Atlantic Anomaly. Y1 - 2017 U6 - https://doi.org/10.1002/2017GL073385 SN - 0094-8276 SN - 1944-8007 VL - 44 SP - 5884 EP - 5891 PB - American Geophysical Union CY - Washington ER - TY - JOUR A1 - Ramage, Justine Lucille A1 - Irrgang, Anna Maria A1 - Herzschuh, Ulrike A1 - Morgenstern, Anne A1 - Couture, Nicole A1 - Lantuit, Hugues T1 - Terrain controls on the occurrence of coastal retrogressive thaw slumps along the Yukon Coast, Canada JF - Journal of geophysical research : Earth surface N2 - Retrogressive thaw slumps (RTSs) are among the most active landforms in the Arctic; their number has increased significantly over the past decades. While processes initiating discrete RTSs are well identified, the major terrain controls on the development of coastal RTSs at a regional scale are not yet defined. Our research reveals the main geomorphic factors that determine the development of RTSs along a 238km segment of the Yukon Coast, Canada. We (1) show the current extent of RTSs, (2) ascertain the factors controlling their activity and initiation, and (3) explain the spatial differences in the density and areal coverage of RTSs. We mapped and classified 287 RTSs using high-resolution satellite images acquired in 2011. We highlighted the main terrain controls over their development using univariate regression trees model. Coastal geomorphology influenced both the activity and initiation of RTSs: active RTSs and RTSs initiated after 1972 occurred primarily on terrains with slope angles greater than 3.9 degrees and 5.9 degrees, respectively. The density and areal coverage of RTSs were constrained by the volume and thickness of massive ice bodies. Differences in rates of coastal change along the coast did not affect the model. We infer that rates of coastal change averaged over a 39year period are unable to reflect the complex relationship between RTSs and coastline dynamics. We emphasize the need for large-scale studies of RTSs to evaluate their impact on the ecosystem and to measure their contribution to the global carbon budget. Plain Language Summary Retrogressive thaw slumps, henceforth slumps are a type of landslides that occur when permafrost thaws. Slumps are active landforms: they develop quickly and extend over several hectares. Satellite imagery allows to map such slumps over large areas. Our research shows where slumps develop along a 238 km segment of the Yukon Coast in Canada and explains which environments are most suitable for slump occurrence. We found that active and newly developed slumps were triggered where coastal slopes were greater than 3.9 degrees and 5.9 degrees, respectively. We explain that coastal erosion influences the development of slumps by modifying coastal slopes. We found that the highest density of slumps as well as the largest slumps occurred on terrains with high amounts of ice bodies in the ground. This study provides tools to better identify areas in the Arctic that are prone to slump development. KW - permafrost degradation KW - retrogressive thaw slumps KW - coastal erosion KW - Arctic KW - coastal geomorphology Y1 - 2017 U6 - https://doi.org/10.1002/2017JF004231 SN - 2169-9003 SN - 2169-9011 VL - 122 SP - 1619 EP - 1634 PB - American Geophysical Union CY - Washington ER - TY - JOUR A1 - Rach, Oliver A1 - Kahmen, Ansgar A1 - Brauer, Achim A1 - Sachse, Dirk T1 - A dual-biomarker approach for quantification of changes in relative humidity from sedimentary lipid D/H ratios JF - Climate of the past : an interactive open access journal of the European Geosciences Union N2 - Past climatic change can be reconstructed from sedimentary archives by a number of proxies. However, few methods exist to directly estimate hydrological changes and even fewer result in quantitative data, impeding our understanding of the timing, magnitude and mechanisms of hydrological changes. Here we present a novel approach based on delta H-2 values of sedimentary lipid biomarkers in combination with plant physiological modeling to extract quantitative information on past changes in relative humidity. Our initial application to an annually laminated lacustrine sediment sequence from western Europe deposited during the Younger Dryas cold period revealed relative humidity changes of up to 15% over sub-centennial timescales, leading to major ecosystem changes, in agreement with palynological data from the region. We show that by combining organic geochemical methods and mechanistic plant physiological models on well characterized lacustrine archives it is possible to extract quantitative ecohydrological parameters from sedimentary lipid biomarker delta H-2 data. Y1 - 2017 U6 - https://doi.org/10.5194/cp-13-741-2017 SN - 1814-9324 SN - 1814-9332 VL - 13 SP - 741 EP - 757 PB - Copernicus CY - Göttingen ER - TY - JOUR A1 - Rach, Oliver A1 - Engels, S. A1 - Kahmen, A. A1 - Brauer, Achim A1 - Martin-Puertas, C. A1 - van Geel, B. A1 - Sachse, Dirk T1 - Hydrological and ecological changes in western Europe between 3200 and 2000 years BP derived from lipid biomarker delta D values in lake Meerfelder Maar sediments JF - Quaternary science reviews : the international multidisciplinary research and review journal N2 - One of the most significant Late Holocene climate shifts occurred around 2800 years ago, when cooler and wetter climate conditions established in western Europe. This shift coincided with an abrupt change in regional atmospheric circulation between 2760 and 2560 cal years BP, which has been linked to a grand solar minimum with the same duration (the Homeric Minimum). We investigated the temporal sequence of hydroclimatic and vegetation changes across this interval of climatic change (Homeric climate oscillation) by using lipid biomarker stable hydrogen isotope ratios (ED values) and pollen assemblages from the annually-laminated sediment record from lake Meerfelder Maar (Germany). Over the investigated interval (3200-2000 varve years BP), terrestrial lipid biomarker ED showed a gradual trend to more negative values, consistent with the western Europe long-term climate trend of the Late Holocene. At ca. 2640 varve years BP we identified a strong increase in aquatic plants and algal remains, indicating a rapid change in the aquatic ecosystem superimposed on this long-term trend. Interestingly, this aquatic ecosystem change was accompanied by large changes in ED values of aquatic lipid biomarkers, such as nC(21) and nC(23) (by between 22 and 30%(0)). As these variations cannot solely be explained by hydroclimate changes, we suggest that these changes in the Wag value were influenced by changes in n-alkane source organisms. Our results illustrate that if ubiquitous aquatic lipid biomarkers are derived from a limited pool of organisms, changes in lake ecology can be a driving factor for variations on sedimentary lipid MN values, which then could be easily misinterpreted in terms of hydro climatic changes. (C) 2017 Elsevier Ltd. All rights reserved. KW - Holocene KW - Climate dynamics KW - Paleoclimatology KW - Western Europe KW - Continental biomarkers KW - Organic geochemistry KW - Stable isotopes KW - Vegetation dynamics Y1 - 2017 U6 - https://doi.org/10.1016/j.quascirev.2017.07.019 SN - 0277-3791 VL - 172 SP - 44 EP - 54 PB - Elsevier CY - Oxford ER - TY - JOUR A1 - Purinton, Benjamin A1 - Bookhagen, Bodo T1 - Validation of digital elevation models (DEMs) and comparison of geomorphic metrics on the southern Central Andean Plateau JF - Earth surface dynamics N2 - In this study, we validate and compare elevation accuracy and geomorphic metrics of satellite-derived digital elevation models (DEMs) on the southern Central Andean Plateau. The plateau has an average elevation of 3.7 km and is characterized by diverse topography and relief, lack of vegetation, and clear skies that create ideal conditions for remote sensing. At 30m resolution, SRTM-C, ASTER GDEM2, stacked ASTER L1A stereopair DEM, ALOS World 3D, and TanDEM-X have been analyzed. The higher-resolution datasets include 12m TanDEM-X, 10m single-CoSSC TerraSAR-X/TanDEM-X DEMs, and 5m ALOS World 3D. These DEMs are state of the art for optical (ASTER and ALOS) and radar (SRTM-C and TanDEM-X) spaceborne sensors. We assessed vertical accuracy by comparing standard deviations of the DEM elevation versus 307 509 differential GPS measurements across 4000m of elevation. For the 30m DEMs, the ASTER datasets had the highest vertical standard deviation at > 6.5 m, whereas the SRTM-C, ALOS World 3D, and TanDEM-X were all < 3.5 m. Higher-resolution DEMs generally had lower uncertainty, with both the 12m TanDEM-X and 5m ALOSWorld 3D having < 2m vertical standard deviation. Analysis of vertical uncertainty with respect to terrain elevation, slope, and aspect revealed the low uncertainty across these attributes for SRTM-C (30 m), TanDEM-X (12–30 m), and ALOS World 3D (5–30 m). Single-CoSSC TerraSAR-X/TanDEM-X 10m DEMs and the 30m ASTER GDEM2 displayed slight aspect biases, which were removed in their stacked counterparts (TanDEM-X and ASTER Stack). Based on low vertical standard deviations and visual inspection alongside optical satellite data, we selected the 30m SRTM-C, 12–30m TanDEM-X, 10m single-CoSSC TerraSAR-X/TanDEM-X, and 5m ALOS World 3D for geomorphic metric comparison in a 66 km2 catchment with a distinct river knickpoint. Consistent m=n values were found using chi plot channel profile analysis, regardless of DEM type and spatial resolution. Slope, curvature, and drainage area were calculated and plotting schemes were used to assess basin-wide differences in the hillslope-to-valley transition related to the knickpoint. While slope and hillslope length measurements vary little between datasets, curvature displays higher magnitude measurements with fining resolution. This is especially true for the optical 5m ALOS World 3D DEM, which demonstrated high-frequency noise in 2–8 pixel steps through a Fourier frequency analysis. The improvements in accurate space-radar DEMs (e.g., TanDEM-X) for geomorphometry are promising, but airborne or terrestrial data are still necessary for meter-scale analysis. Y1 - 2017 U6 - https://doi.org/10.5194/esurf-5-211-2017 SN - 2196-632X SN - 2196-6311 VL - 5 IS - 2 SP - 211 EP - 237 PB - Copernicus Publ. CY - Göttingen ER - TY - JOUR A1 - Purinton, Benjamin A1 - Bookhagen, Bodo T1 - Validation of digital elevation models (DEMs) and comparison of geomorphic metrics on the southern Central Andean Plateau JF - Earth surface dynamics N2 - In this study, we validate and compare elevation accuracy and geomorphic metrics of satellite-derived digital elevation models (DEMs) on the southern Central Andean Plateau. The plateau has an average elevation of 3.7 km and is characterized by diverse topography and relief, lack of vegetation, and clear skies that create ideal conditions for remote sensing. At 30m resolution, SRTM-C, ASTER GDEM2, stacked ASTER L1A stereopair DEM, ALOS World 3D, and TanDEM-X have been analyzed. The higher-resolution datasets include 12m TanDEM-X, 10m single-CoSSC TerraSAR-X/TanDEM-X DEMs, and 5m ALOS World 3D. These DEMs are state of the art for optical (ASTER and ALOS) and radar (SRTM-C and TanDEM-X) spaceborne sensors. We assessed vertical accuracy by comparing standard deviations of the DEM elevation versus 307 509 differential GPS measurements across 4000m of elevation. For the 30m DEMs, the ASTER datasets had the highest vertical standard deviation at > 6.5 m, whereas the SRTM-C, ALOS World 3D, and TanDEM-X were all < 3.5 m. Higher-resolution DEMs generally had lower uncertainty, with both the 12m TanDEM-X and 5m ALOSWorld 3D having < 2m vertical standard deviation. Analysis of vertical uncertainty with respect to terrain elevation, slope, and aspect revealed the low uncertainty across these attributes for SRTM-C (30 m), TanDEM-X (12-30 m), and ALOS World 3D (5-30 m). Single-CoSSC TerraSAR-X/TanDEM-X 10m DEMs and the 30m ASTER GDEM2 displayed slight aspect biases, which were removed in their stacked counterparts (TanDEM-X and ASTER Stack). Based on low vertical standard deviations and visual inspection alongside optical satellite data, we selected the 30m SRTM-C, 12-30m TanDEM-X, 10m single-CoSSC TerraSAR-X/TanDEM-X, and 5m ALOS World 3D for geomorphic metric comparison in a 66 km2 catchment with a distinct river knickpoint. Consistent m = n values were found using chi plot channel profile analysis, regardless of DEM type and spatial resolution. Slope, curvature, and drainage area were calculated and plotting schemes were used to assess basin-wide differences in the hillslope-to-valley transition related to the knickpoint. While slope and hillslope length measurements vary little between datasets, curvature displays higher magnitude measurements with fining resolution. This is especially true for the optical 5m ALOS World 3D DEM, which demonstrated high-frequency noise in 2-8 pixel steps through a Fourier frequency analysis. The improvements in accurate space-radar DEMs (e. g., TanDEM-X) for geomorphometry are promising, but airborne or terrestrial data are still necessary for meter-scale analysis. Y1 - 2017 U6 - https://doi.org/10.5194/esurf-5-211-2017 SN - 2196-6311 SN - 2196-632X VL - 5 SP - 211 EP - 237 PB - Copernicus CY - Göttingen ER - TY - JOUR A1 - Proborukmi, Maria Sekar A1 - Urban, Brigitte A1 - Mischke, Steffen A1 - Mienis, Henk K. A1 - Melamed, Yoel A1 - Dupont-Nivet, Guillaume A1 - Jourdan, Fred A1 - Goren-Inbar, Naama T1 - Evidence for climatic changes around the Matuyama-Brunhes Boundary (MBB) inferred from a multi-proxy palaeoenvironmental study of the GBY#2 core, Jordan River Valley, Israel JF - Palaeogeography, palaeoclimatology, palaeoecology : an international journal for the geo-sciences N2 - The Acheulian site of Gesher Benot Ya‘aqov (GBY) in the Upper Jordan Valley revealed important data on environment and material culture, as well as evidence for hominin behavioural and cognitive patterns documented at the margins of the Hula Palaeo-lake. A 50 m long core (GBY#2) drilled at the archaeological site has provided a long Pleistocene geological, environmental and climatological record, which expands the existing knowledge of hominin-habitat relationships. Bracketed by two basalt flows dated by 40Ar/39Ar and based on the identification of the Matuyama-Brunhes Boundary (MBB) and correlation with the GBY excavation site, the sedimentary sequence provides the climatic history around the MBB. Multi-proxy data including pollen and non-pollen palynomorphs, macro-botanical remains, molluscs and ostracods provide evidence for lake and lake-margin environments during Marine Isotope Stages (MIS) 20 and 19. Semi-moist conditions were followed by a pronounced dry phase during MIS 20, and warm and moist conditions with Quercus-Pistacia woodlands prevailed during MIS 19. In contrast to the reconstructed climate change from relatively dry to moister conditions, the depositional environment developed from an open-water lake during MIS 20 to a lake margin environment in MIS 19. Generally shallower conditions at the core site in MIS 19 resulted from the progradation of the lake shore due to the filling of the basin. Micro-charcoal analysis suggests a likelihood of human-induced fire in some parts of the core, which can be correlated with artefact-containing layers of the GBY excavation site. The Hula Palaeo-lake region provided an ideal niche for hominins and other vertebrates during global glacial-interglacial climate fluctuations at the end of the Early Pleistocene. KW - Hula Basin KW - Levant KW - Hominins KW - Pollen record KW - Plant macro-remains Y1 - 2017 U6 - https://doi.org/10.1016/j.palaeo.2017.10.007 SN - 0031-0182 SN - 1872-616X VL - 489 SP - 166 EP - 185 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Pradhan, Prajal A1 - Costa, Luís Fílípe Carvalho da A1 - Rybski, Diego A1 - Lucht, Wolfgang A1 - Kropp, Jürgen T1 - A Systematic Study of Sustainable Development Goal (SDG) Interactions JF - Earths Future N2 - Sustainable development goals (SDGs) have set the 2030 agenda to transform our world by tackling multiple challenges humankind is facing to ensure well-being, economic prosperity, and environmental protection. In contrast to conventional development agendas focusing on a restricted set of dimensions, the SDGs provide a holistic and multidimensional view on development. Hence, interactions among the SDGs may cause diverging results. To analyze the SDG interactions we systematize the identification of synergies and trade-offs using official SDG indicator data for 227 countries. A significant positive correlation between a pair of SDG indicators is classified as a synergy while a significant negative correlation is classified as a trade-off. We rank synergies and trade-offs between SDGs pairs on global and country scales in order to identify the most frequent SDG interactions. For a given SDG, positive correlations between indicator pairs were found to outweigh the negative ones in most countries. Among SDGs the positive and negative correlations between indicator pairs allowed for the identification of particular global patterns. SDG 1 (No poverty) has synergetic relationship with most of the other goals, whereas SDG 12 (Responsible consumption and production) is the goal most commonly associated with trade-offs. The attainment of the SDG agenda will greatly depend on whether the identified synergies among the goals can be leveraged. In addition, the highlighted trade-offs, which constitute obstacles in achieving the SDGs, need to be negotiated and made structurally nonobstructive by deeper changes in the current strategies. Y1 - 2017 U6 - https://doi.org/10.1002/2017EF000632 SN - 2328-4277 VL - 5 SP - 1169 EP - 1179 PB - Wiley CY - Hoboken ER - TY - JOUR A1 - Pokorny, Richard A1 - Krmicek, Lukas A1 - Sudo, Masafumi T1 - An endemic ichnoassemblage from a late Miocene paleolake in SE Iceland JF - Palaeogeography, palaeoclimatology, palaeoecology : an international journal for the geo-sciences N2 - In Porisdalur valley, a small relict of a sedimentary body was identified in southeastern Iceland. It probably represents a remnant of the deep, tectonically arranged paleolake (Late Miocene, 8-9 Ma), and filled by volcaniclastic material from nearby, active volcanic centers. In the profile of tuffitic sandstone, siltstone and claystone, the ripple-bedding layers, molds and flute casts indicate periodic mass flow episodes. In the sedimentary profile, the characteristic arrangement of sediments is evident, showing features of the Bouma sequences. In the claystone layers, deposited during episodes of lowest kinetic energy, a specific ichnoassemblage was found, represented by Thorichnus ramosus igen. et isp. nov., T. corniculatus igen. et isp. nov., Mammillichnis jakubi isp. nov., Helminthoidichnites multilaqueatus comb. nov., Vamaspor jachymi igen. et isp. nov. and five preliminarily identified trace fossils. The assemblage belongs to Mermia ichnofacies, the nonmarine representative of an ichnofacies, developed in a turbiditic environment; most of identified trace fossils are so far endemic. (C) 2017 Elsevier B.V. All rights reserved. KW - Turbidite KW - Mermia ichnofacies KW - Thorichnus-Vatnaspor ichnoassemblage Y1 - 2017 U6 - https://doi.org/10.1016/j.palaeo.2017.07.033 SN - 0031-0182 SN - 1872-616X VL - 485 SP - 761 EP - 773 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Planert, Lars A1 - Behrmann, Jan H. A1 - Jokat, Wilfried A1 - Fromm, Tanja A1 - Ryberg, Trond A1 - Weber, Michael A1 - Haberland, Christian T1 - The wide-angle seismic image of a complex rifted margin, offshore North Namibia: Implications for the tectonics of continental breakup JF - Tectonophysics : international journal of geotectonics and the geology and physics of the interior of the earth N2 - Voluminous magmatism during the South Atlantic opening has been considered as a classical example for plume related continental breakup. We present a study of the crustal structure around Walvis Ridge, near the intersection with the African margin. Two wide-angle seismic profiles were acquired. One is oriented NNW–SSE, following the continent–ocean transition and crossing Walvis Ridge. A second amphibious profile runs NW–SE from the Angola Basin into continental Namibia. At the continent–ocean boundary (COB) the mafic crust beneath Walvis Ridge is up to 33 km thick, with a pronounced high-velocity lower crustal body. Towards the south there is a smooth transition to 20–25 km thick crust underlying the COB in the Walvis Basin, with a similar velocity structure, indicating a gabbroic lower crust with associated cumulates at the base. The northern boundary of Walvis Ridge towards the Angola Basin shows a sudden change to oceanic crust only 4–6 km thick, coincident with the projection of the Florianopolis Fracture Zone, one of the most prominent tectonic features of the South Atlantic ocean basin. In the amphibious profile the COB is defined by a sharp transition from oceanic to rifted continental crust, with a magmatic overprint landward of the intersection of Walvis Ridge with the Namibian margin. The continental crust beneath the Congo Craton is 40 km thick, shoaling to 35 km further SE. The velocity models show that massive high-velocity gabbroic intrusives are restricted to a narrow zone directly underneath Walvis Ridge and the COB in the south. This distribution of rift-related magmatism is not easily reconciled with models of continental breakup following the establishment of a large, axially symmetric plume in the Earth's mantle. Rift-related lithospheric stretching and associated transform faulting play an overriding role in locating magmatism, dividing the margin in a magma-dominated southern and an essentially amagmatic northern segment. KW - Wide-angle seismic KW - Crustal structure KW - Walvis Ridge KW - Hotspot KW - Rifted continental margin KW - South Atlantic Y1 - 2017 U6 - https://doi.org/10.1016/j.tecto.2016.06.024 SN - 0040-1951 SN - 1879-3266 VL - 716 SP - 130 EP - 148 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Pilz, Tobias A1 - Francke, Till A1 - Bronstert, Axel T1 - lumpR 2.0.0: an R package facilitating landscape discretisation for hillslope-based hydrological models JF - Geoscientific model development : an interactive open access journal of the European Geosciences Union N2 - The characteristics of a landscape pose essential factors for hydrological processes. Therefore, an adequate representation of the landscape of a catchment in hydrological models is vital. However, many of such models exist differing, amongst others, in spatial concept and discretisation. The latter constitutes an essential pre-processing step, for which many different algorithms along with numerous software implementations exist. In that context, existing solutions are often model specific, commercial, or depend on commercial back-end software, and allow only a limited or no workflow automation at all. Consequently, a new package for the scientific software and scripting environment R, called lumpR, was developed. lumpR employs an algorithm for hillslope-based landscape discretisation directed to large-scale application via a hierarchical multi-scale approach. The package addresses existing limitations as it is free and open source, easily extendible to other hydrological models, and the workflow can be fully automated. Moreover, it is user-friendly as the direct coupling to a GIS allows for immediate visual inspection and manual adjustment. Sufficient control is furthermore retained via parameter specification and the option to include expert knowledge. Conversely, completely automatic operation also allows for extensive analysis of aspects related to landscape discretisation. In a case study, the application of the package is presented. A sensitivity analysis of the most important discretisation parameters demonstrates its efficient workflow automation. Considering multiple streamflow metrics, the employed model proved reasonably robust to the discretisation parameters. However, parameters determining the sizes of subbasins and hillslopes proved to be more important than the others, including the number of representative hillslopes, the number of attributes employed for the lumping algorithm, and the number of sub-discretisations of the representative hillslopes. Y1 - 2017 U6 - https://doi.org/10.5194/gmd-10-3001-2017 SN - 1991-959X SN - 1991-9603 VL - 10 SP - 3001 EP - 3023 PB - Copernicus CY - Göttingen ER - TY - JOUR A1 - Pilz, Tobias A1 - Francke, Till A1 - Bronstert, Axel T1 - lumpR 2.0.0: an R package facilitating landscape discretisation for hillslope-based hydrological models JF - Geoscientific model development N2 - The characteristics of a landscape pose essential factors for hydrological processes. Therefore, an adequate representation of the landscape of a catchment in hydrological models is vital. However, many of such models exist differing, amongst others, in spatial concept and discretisation. The latter constitutes an essential pre-processing step, for which many different algorithms along with numerous software implementations exist. In that context, existing solutions are often model specific, commercial, or depend on commercial back-end software, and allow only a limited or no workflow automation at all. Consequently, a new package for the scientific software and scripting environment R, called lumpR, was developed. lumpR employs an algorithm for hillslope-based landscape discretisation directed to large-scale application via a hierarchical multi-scale approach. The package addresses existing limitations as it is free and open source, easily extendible to other hydrological models, and the workflow can be fully automated. Moreover, it is user-friendly as the direct coupling to a GIS allows for immediate visual inspection and manual adjustment. Sufficient control is furthermore retained via parameter specification and the option to include expert knowledge. Conversely, completely automatic operation also allows for extensive analysis of aspects related to landscape discretisation. In a case study, the application of the package is presented. A sensitivity analysis of the most important discretisation parameters demonstrates its efficient workflow automation. Considering multiple streamflow metrics, the employed model proved reasonably robust to the discretisation parameters. However, parameters determining the sizes of subbasins and hillslopes proved to be more important than the others, including the number of representative hillslopes, the number of attributes employed for the lumping algorithm, and the number of sub-discretisations of the representative hillslopes. Y1 - 2017 U6 - https://doi.org/10.5194/gmd-10-3001-2017 SN - 1991-959X SN - 1991-9603 VL - 10 SP - 3001 EP - 3023 PB - Copernicus CY - Göttingen ER - TY - JOUR A1 - Pick, Leonie A1 - Korte, Monika T1 - An annual proxy for the geomagnetic signal of magnetospheric currents on Earth based on observatory data from 1900–2010 JF - Geophysical Journal International N2 - We introduce the Annual Magnetospheric Currents index as long-term proxy for the geomagnetic signal of magnetospheric currents on Earth valid within the time span 1900–2010. Similar to the widely used disturbance storm time and ‘Ring Current’ indices, it is based on geomagnetic observatory data, but provides a realistic absolute level and uncertainty estimates. Crucial aspects to this end are the revision of observatory crustal biases as well as the implementation of a Bayesian inversion accounting for uncertainties in the main field estimate, both required for the index derivation. The observatory choice is based on a minimization of index variance during a reference period spanning 1960–2010. The new index is capable of correcting observatory time series from large-scale external signals in a user-friendly manner. At present the index is only available as annual mean values. An extension to hourly values for the same time span is in progress. KW - Magnetic field variations through time KW - Satellite magnetics KW - Inverse theory KW - Statistical methods KW - Time-series analysis Y1 - 2017 U6 - https://doi.org/10.1093/gji/ggx367 SN - 1365-246X SN - 0956-540X VL - 211 IS - 2 SP - 1223 EP - 1236 PB - Oxford Univ. Press CY - Oxford ER - TY - JOUR A1 - Perez-Lopez, Raul A1 - Martin-Velazquez, Saul A1 - Sanchez-Moral, Sergio A1 - Patyniak, Magda A1 - Lopez-Gutierrez, Jose A1 - Cuezva, Soledad A1 - Lario, J. A1 - Silva, P. G. A1 - Rodriguez-Pascua, M. A. A1 - Giner-Robles, J. L. T1 - New insights on speleoseismology: The geothermal gradient and heat flow values in caves for the study of active faults JF - Quaternary international : the journal of the International Union for Quaternary Research N2 - Normally in paleoseismology, the study of the tectonic slip-rate is performed in trenches on the fault scarp, or by the estimation of fault movements from the geomorphic features. In this work, we have carried out a paleoseismic analysis of the Benis Fault, located in southeast Spain, combined with a geothermal analysis inside a deep cave related to the fault (-350 m). Thus, we have estimated the last earthquake magnitude and time of occurrence from evidence of ceiling collapse and displaced carbonate blocks inside a cave, which is developed across the fault. The magnitude was obtained from the application of the empirical relationship of the fault parameters and coseismic vertical displacement, yielding a value ranging between M 5.9 and M 6.5. Moreover, we dated this paleoearthquake by the paleontological record of a "Lynx pardinus spelaea", with an age of 65 +/- 18 ka BP. Additionally, we have measured the thermal profile of the Benis Cave (-350 m of depth), from single rock point temperature measurements during 2 years. The temperature profile shows three different parts inside the cave, the shallow heterogeneous thermal zone till 50 m depth; the homogeneous thermal zone 150 m till with constant temperature and the hetero-thermal deep zone, deeper than 150 m and till the deepest zone (350 m). Furthermore, we have estimated the Vertical Geothermal Gradient, 1.85 degrees C/100 m for the deepest zone (-150; -290 m). The temperature increases with depth, showing a reverse thermal profile in comparison with normal gradients in deep caves. Finally, we have calculated the heat flux of 0.46 mWm(2). (C) 2016 Elsevier Ltd and INQUA. All rights reserved. KW - Speleoseismology KW - Active fault KW - Cave KW - Slip-rate KW - Heat flux Y1 - 2017 U6 - https://doi.org/10.1016/j.quaint.2016.11.026 SN - 1040-6182 SN - 1873-4553 VL - 451 SP - 165 EP - 175 PB - Elsevier CY - Oxford ER - TY - JOUR A1 - Pedoja, K. A1 - Jara Muñoz, Julius A1 - De Gelder, G. A1 - Robertson, J. A1 - Meschis, M. A1 - Fernandez-Blanco, D. A1 - Nexer, M. A1 - Poprawski, Y. A1 - Dugue, O. A1 - Delcaillau, B. A1 - Bessin, P. A1 - Benabdelouahed, M. A1 - Authemayou, C. A1 - Husson, L. A1 - Regard, V. A1 - Menier, D. A1 - Pinel, B. T1 - Neogene-Quaternary slow coastal uplift of Western Europe through the perspective of sequences of strandlines from the Cotentin Peninsula (Normandy, France) JF - Geomorphology : an international journal on pure and applied geomorphology N2 - The Cotentin Peninsula (Normandy, France) displays sequences of marine terraces and rasas, the latter being wide Late Cenozoic coastal erosion surfaces, that are typical of Western European coasts in Portugal, Spain, France and southern England. Remote sensing imagery and field mapping enabled reappraisal of the Cotentin coastal sequences. From bottom to top, the N Cotentin sequence includes four previously recognized Pleistocene marine terraces (T1 to T4) at elevations <40 m as well as four higher and older rasas (R1 to R4) reaching 200 +/- 5 m in elevation. Low-standing marine terraces are not observed in the central part of the Peninsula and a limited number of terraces are described to the south. The high-standing rasas are widespread all over the peninsula. Such strandline distributions reveal major changes during the Late Cenozoic. Progressive uplift of an irregular sea-floor led to subaerial exposure of bathymetric highs that were carved into rocky platforms, rasas and marine terraces. Eventually, five main islands coalesced and connected to the mainland to the south to form the Cotentin Peninsula. On the basis of previous dating of the last interglacial maximum terrace (i.e. Marine Isotopic Stage, MIS 5e), sequential morphostratigraphy and modelling, we have reappraised uplift rates and derived: (i) mean Upper Pleistocene (i.e. since MIS 5e similar to 122 +/- 6 ka, i.e. kilo annum) apparent uplift rates of 0.04 +/- 0.01 mm/yr, (ii) mean Middle Pleistocene eustasy-corrected uplift rates of 0.09 +/- 0.03 mm/yr, and (iii) low mean Pleistocene uplift rates of 0.01 mm/yr. Extrapolations of these slow rates combined with geological evidence implies that the formation of the sequences from the Cotentin Peninsula occurred between 3 Ma (Pliocene) and 15 Ma (Miocene), which cannot be narrowed down further without additional research. Along the coasts of Western Europe, sequences of marine terraces and rasas are widespread (169 preserve the MIS Se benchmark). In Spain, Portugal, S England and other parts of western France, the sequences morphostratigraphy is very similar to that of Cotentin. The onset of such Western European sequences occurred during the Miocene (e.g. Spain) or Pliocene (e.g. Portugal). We interpret this Neogene-Quaternary coastal uplift as a symptom of the increasing lithospheric compression that accompanies Cenozoic orogenies. (C) 2017 Elsevier B.V. All rights reserved. KW - Marine terrace KW - Rasa KW - Cotentin and Western Europe KW - Neogene and Quaternary coastal uplift Y1 - 2017 U6 - https://doi.org/10.1016/j.geomorph.2017.11.021 SN - 0169-555X SN - 1872-695X VL - 303 SP - 338 EP - 356 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Patyniak, Magda A1 - Landgraf, Angela A1 - Dzhumabaeva, Atyrgul A1 - Abdrakhmatov, Kanatbek E. A1 - Rosenwinkel, Swenja A1 - Korup, Oliver A1 - Preusser, Frank A1 - Fohlmeister, Jens Bernd A1 - Arrowsmith, J. Ramon A1 - Strecker, Manfred T1 - Paleoseismic Record of Three Holocene Earthquakes Rupturing the Issyk-Ata Fault near Bishkek, North Kyrgyzstan JF - Bulletin of the Seismological Society of America N2 - The northern edge of the western central Tien Shan range is bounded by the Issyk-Ata fault situated south of Bishkek, the capital of Kyrgyzstan. Contraction in this thick-skinned orogen occurs with low-strain accumulation and long earthquake recurrence intervals. In the nineteenth to twentieth centuries, a sequence of large earthquakes with magnitudes between 6.9 and 8 affected the northern Tien Shan but left nearly the entire extent of the Issyk-Ata fault unruptured. Here, the only known historic earthquake ruptured in A.D. 1885 (M6.9) along the western end of the Issyk-Ata fault. Because earthquakes in low-strain regions often tend to cluster in time and may promote failure along nearby structures, the earthquake history of the northern Tien Shan represents an exceptional structural setting for studying fault behavior affected by an intraplate earthquake sequence. We present a paleoseismological study from one site (Belek) along the Issyk-Ata fault located east of the A.D. 1885 epicentral area. Our analysis combines a range of tools, including photogrammetry, differential Global Positioning System, 3D visualization, and age modeling with different dating methods (infrared stimulated luminescence, radiocarbon, U-series) to improve the reliability of an event chronology for the trench stratigraphy and fault geometry. We were able to distinguish three different surfacerupturing paleoearthquakes; these affected the area before 10.5 +/- 1.1 cal ka B.P., at similar to 5.6 +/- 1.0 cal ka B.P., and at similar to 630 +/- 100 cal B.P., respectively. Associated paleomagnitudes for the last two earthquakes range between M6.7 and 7.4, with a cumulative slip rate of 0.7 +/- 0.32 mm/yr. We did not find evidence for the A.D. 1885 event at Belek. Our study yielded two main overall results: first, it extends the regional historic and paleoseismic record; second, the documented rupture events along the Issyk-Ata fault suggest that this fault was not affected in its entirety; instead, these events indicate segmented rupture behavior. Y1 - 2017 U6 - https://doi.org/10.1785/0120170083 SN - 0037-1106 SN - 1943-3573 VL - 107 SP - 2721 EP - 2737 PB - Seismological Society of America CY - Albany ER - TY - JOUR A1 - Palagushkina, Olga A1 - Wetterich, Sebastian A1 - Biskaborn, Boris A1 - Nazarova, Larisa B. A1 - Schirrmeister, Lutz A1 - Lenz, Josefine A1 - Schwamborn, Georg A1 - Grosse, Guido T1 - Diatom records and tephra mineralogy in pingo deposits of Seward Peninsula, Alaska JF - Palaeogeography, palaeoclimatology, palaeoecology : an international journal for the geo-sciences N2 - Vast areas of the terrestrial Subarctic and Arctic are underlain by permafrost. Landscape evolution is therefore largely controlled by climate-driven periglacial processes. The response of the frozen ground to late Quaternary warm and cold stages is preserved in permafrost sequences, and deducible by multi-proxy palaeoenvironmental approaches. Here, we analyse radiocarbon-dated mid-Wisconsin Interstadial and Holocene lacustrine deposits preserved in the Kit-1 pingo permafrost sequence combined with water and surface sediment samples from nine modern water bodies on Seward Peninsula (NW Alaska) to reconstruct thermokarst dynamics and determine major abiotic factors that controlled the aquatic ecosystem variability. Our methods comprise taxonomical diatom analyses as well as Detrended Correspondence Analysis (DCA) and Redundancy Analysis (RDA). Our results show, that the fossil diatom record reflects thermokarst lake succession since about 42 C-14 kyr BP. Different thermolcarst lake stages during the mid-Wisconsin Interstadial, the late Wisconsin and the early Holocene are mirrored by changes in diatom abundance, diversity, and ecology. We interpret the taxonomical changes in the fossil diatom assemblages in combination with both modern diatom data from surrounding ponds and existing micropalaeontological, sedimentological and mineralogical data from the pingo sequence. A diatom based quantitative reconstruction of lake water pH indicates changing lake environments during mid-Wisconsin to early Holocene stages. Mineralogical analyses indicate presence of tephra fallout and its impact on fossil diatom communities. Our comparison of modern and fossil diatom communities shows the highest floristic similarity of modern polygon ponds to the corresponding initial (shallow water) development stages of thermolcarst lakes. We conclude, that mid-Wisconsin thermokarst processes in the study area could establish during relatively warm interstadial climate conditions accompanied by increased precipitation due to approaching coasts, while still high continentality and hence high seasonal temperature gradients led to warm summers in the central part of Beringia. (C) 2017 Elsevier B.V. All rights reserved. KW - Microalgae assemblages KW - Palaeoenvironments KW - Thermokarst KW - Late Quaternary KW - Permafrost Y1 - 2017 U6 - https://doi.org/10.1016/j.palaeo.2017.04.006 SN - 0031-0182 SN - 1872-616X VL - 479 SP - 1 EP - 15 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Owen-Smith, T. M. A1 - Ashwal, L. D. A1 - Sudo, Masafumi A1 - Trumbull, Robert B. T1 - Age and Petrogenesis of the Doros Complex, Namibia, and Implications for Early Plume-derived Melts in the Parana-Etendeka LIP JF - Journal of petrology N2 - The early Cretaceous Paraná–Etendeka Large Igneous Province is attributed to the impact of the Tristan mantle plume on the base of the continental lithosphere and the associated opening of the South Atlantic Ocean during the breakup of West Gondwana. Although the geochemistry of the Paraná and Etendeka volcanic rocks has been extensively studied, there is still disagreement on the role of the mantle plume in the production of the magma types observed, because some of their primary compositions are obscured by continental crustal contamination. However, there are related plutonic rocks that preserve mantle signatures. The Doros Complex is a shallow-level mafic intrusion within the Etendeka Province of Namibia. New 39Ar/40Ar step-heating ages for Doros gabbros from this study (weighted mean of 130 ± 1 Ma; 2σ error) confirm contemporaneity with the Paraná–Etendeka magmatic event. The Doros suite yields mean ɛNd values of +5·3 ± 1·0 (1σ; n = 11), initial 87Sr/86Sr = 0·70418 ± 0·00017 (n = 11) and 206Pb/204Pb = 18·11 ± 0·06 (n = 13) at 132 Ma. The clustering of isotopic data and trends in incompatible trace element ratios indicate that all the magmas in the complex were derived from the same mantle source components, during the same melting episode. By quantitative isotopic modelling of mixing processes, we constrain the Doros parental magma to comprise 60–80% melt of a depleted asthenospheric mantle component and 20–40% melt of a more enriched, Tristan plume-derived, asthenospheric component. No lithospheric mantle component is required to explain the Doros magma compositions. The chilled margin to the complex is the only rock type that shows evidence of significant continental crustal contamination, by assimilation of the metasedimentary host-rock upon emplacement. The identification of a substantial Tristan plume component in the Doros source confirms the integral role of the deep-seated thermal anomaly in Paraná–Etendeka magmatism. We show, in addition, that the Doros suite has consistent, strong geochemical affinities with the Tafelkop group ‘ferropicrite’ lavas of the Etendeka Province. This provides crucial evidence in support of Doros as the eruptive site for the Tafelkop lavas, thereby linking the Doros magmatism to the earliest eruptive phase in the Etendeka event. The distinctive chemistry of this magma group has been attributed to relatively deep decompression melting of pyroxenite-bearing material in the heterogeneous Tristan plume head, related to the initial impact of the plume on the base of the lithosphere. KW - radiogenic isotopes KW - ferropicrite magmas KW - layered mafic intrusion KW - Tristan mantle plume KW - Parana-Etendeka Large Igneous Province Y1 - 2017 U6 - https://doi.org/10.1093/petrology/egx021 SN - 0022-3530 SN - 1460-2415 VL - 58 IS - 3 SP - 423 EP - 442 PB - Oxford Univ. Press CY - Oxford ER - TY - JOUR A1 - Otto, Christian A1 - Willner, Sven N. A1 - Wenz, Leonie A1 - Frieler, Katja A1 - Levermann, Anders T1 - Modeling loss-propagation in the global supply network: The dynamic agent-based model acclimate JF - Journal of economic dynamics & control N2 - World markets are highly interlinked and local economies extensively rely on global supply and value chains. Consequently, local production disruptions, for instance caused by extreme weather events, are likely to induce indirect losses along supply chains with potentially global repercussions. These complex loss dynamics represent a challenge for comprehensive disaster risk assessments. Here, we introduce the numerical agent-based model acclimate designed to analyze the cascading of economic losses in the global supply network. Using national sectors as agents, we apply the model to study the global propagation of losses induced by stylized disasters. We find that indirect losses can become comparable in size to direct ones, but can be efficiently mitigated by warehousing and idle capacities. Consequently, a comprehensive risk assessment cannot focus solely on first-tier suppliers, but has to take the whole supply chain into account. To render the supply network climate-proof, national adaptation policies have to be complemented by international adaptation efforts. In that regard, our model can be employed to assess reasonable leverage points and to identify dynamic bottlenecks inaccessible to static analyses. (C) 2017 Elsevier B.V. All rights reserved. KW - Disaster impact analysis KW - Higher-order effects KW - Economic network KW - Resilience KW - Dynamic input-output model KW - Agent-based modeling Y1 - 2017 U6 - https://doi.org/10.1016/j.jedc.2017.08.001 SN - 0165-1889 SN - 1879-1743 VL - 83 SP - 232 EP - 269 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Omrani, Hadi A1 - Moazzen, Mohssen A1 - Oberhänsli, Roland A1 - Moslempour, Mohammad Elyas T1 - Iranshahr blueschist: subduction of the inner Makran oceanic crust JF - Journal of metamorphic geology N2 - The Makran accretionary prism in SE Iran and SW Pakistan is one of the most extensive subduction accretions on Earth. It is characterized by intense folding, thrust faulting and dislocation of the Cenozoic units that consist of sedimentary, igneous and metamorphic rocks. Rock units forming the northern Makran ophiolites are amalgamated as a melange. Metamorphic rocks, including greenschist, amphibolite and blueschist, resulted from metamorphism of mafic rocks and serpentinites. In spite of the geodynamic significance of blueschist in this area, it has been rarely studied. Peak metamorphic phases of the northern Makran mafic blueschist in the Iranshahr area are glaucophane, phengite, quartz +/- omphacite+epidote. Post peak minerals are chlorite, albite and calcic amphibole. Blueschist facies metasedimentary rocks contain garnet, phengite, albite and epidote in the matrix and as inclusions in glaucophane. The calculated P-T pseudosection for a representative metabasic glaucophane schist yields peak pressure and temperature of 11.5-15kbar at 400-510 degrees C. These rocks experienced retrograde metamorphism from blueschist to greenschist facies (350-450 degrees C and 7-8kbar) during exhumation. A back arc basin was formed due to northward subduction of Neotethys under Eurasia (Lut block). Exhumation of the high-pressure metamorphic rocks in northern Makran occurred contemporarily with subduction. Several reverse faults played an important role in exhumation of the ophiolitic and HP-LT rocks. The presence of serpentinite shows the possible role of a serpentinite diapir for exhumation of the blueschist. A tectonic model is proposed here for metamorphism and exhumation of oceanic crust and accretionary sedimentary rocks of the Makran area. Vast accretion of subducted materials caused southward migration of the shore. KW - back arc basin KW - Bajgan/Durkan KW - HP-LT metamorphic rocks KW - Iran KW - Lut Blocks KW - Northern Makran KW - subduction and exhumation Y1 - 2017 U6 - https://doi.org/10.1111/jmg.12236 SN - 0263-4929 SN - 1525-1314 VL - 35 SP - 373 EP - 392 PB - Wiley CY - Hoboken ER - TY - JOUR A1 - Olatunji, Akinade S. A1 - Kolawole, Tesleem O. A1 - Oloruntola, Moroof A1 - Günter, Christina T1 - Evaluation of pollution of soils and particulate matter around metal recycling factories in Southwestern Nigeria JF - Journal of health and pollutuin N2 - Background. Metal recycling factories (MRFs) have developed rapidly in Nigeria as recycling policies have been increasingly embraced. These MRFs are point sources for introducing potentially toxic elements (PTEs) into environmental media. Objectives. The aim of this study was to determine the constituents (elemental and mineralogy) of the wastes (slag and particulate matter, (PM)) and soils around the MRFs and to determine the level of pollution within the area. Methods. Sixty samples (30 slag samples, 15 soil samples and 15 PM samples) were collected for this study. The soils, slag and PM samples were analyzed for elemental constituents using inductively coupled plasma optical emission spectrometry. Mineralogy of the PM was determined using scanning electron microscope-energy dispersive spectroscopy (SEM-EDS), and soil mineralogy was determined by an X-ray diffractometer (XRD). Results. The results of the soil analyses revealed the following concentrations for the selected metals in mg/kg include lead (Pb) (21.0-2399.0), zinc (Zn) (56.0-4188.0), copper (Cu) (10.0-1470.0), nickel (Ni) (6.0-215.0), chromium (Cr) (921.0-1737.0) and cadmium (Cd) (below detectable limit (Bdl)-18.1). For the slags the results were Pb (68.0-.333.0), Zn (1364.0-3062), Cu (119.0-1470.0), Ni (12.0-675.0), Cr (297-1737) and Cd (Bdl-15.8). The results in mu g/g for the metal analysis in PM were Pb (4.6-160.0), Zn (18.0-471.0), Cu (2.5-11.0), Ni (0.8-4.2), and Cr (2.5-11.0), while Cd was undetected. The slags are currently utilized for filling the foundations of buildings and roads, providing additional pathways for the introduction of PTEs into the environment from the suspended materials generated from mechanical breakdown of the slags. Conclusions. The MRFs were found to have impacted the quality of environmental media through the introduction of PTEs, impairing soil quality, in addition to PM, which can have detrimental health consequences. Further studies on the health implications of these pollutants and their impacts on human health are needed. Competing Interests. The authors declare no competing financial interests KW - potentially toxic elements KW - metal recycling plants KW - slags KW - pollution indices Y1 - 2017 U6 - https://doi.org/10.5696/2156-9614-8.17.20 SN - 2156-9614 VL - 8 IS - 17 SP - 20 EP - 30 PB - Blacksmith Institute and Pure Earth CY - New York ER - TY - JOUR A1 - Oguntunde, Philip G. A1 - Abiodun, Babatunde Joseph A1 - Lischeid, Gunnar T1 - Impacts of climate change on hydro-meteorological drought over the Volta Basin, West Africa JF - Global and planetary change N2 - This study examines the characteristics of drought in the Volta River Basin (VRB), investigates the influence of drought on the streamflow, and projects the impacts of future climate change on the drought. A combination of observation data and regional climate simulations of past and future climates (1970-2013, 2046-2065, and 2081-2100) were analyzed for the study. The Standardized Precipitation Index (SPI) and Standardized Precipitation and Evapotranspiration (SPEI) were used to characterize drought while the Standardized Runoff Index (SRI) were used to quantify runoff. Results of the study show that the historical pattern of drought is generally consistent with previous studies over the Basin and most part of West Africa. RCA ensemble medians (RMED) give realistic simulations of drought characteristics and area extent over the Basin and the sub-catchments in the past climate. Generally, an increase in drought intensity and spatial extent are projected over VRB for SPEI and SPI, but the magnitude of increase is higher with SPEI than with SPI. Drought frequency (events per decade) may be magnified by a factor of 1.2, (2046-2065) to 1.6 (2081-2100) compared to the present day episodes in the basin. The coupling between streamflow and drought episodes was very strong (P < 0.05) for the 1-16-year band before the 1970 but showed strong correlation all through the time series period for the 4-8 -years band. Runoff was highly sensitive to precipitation in the VRB and a 2-3 month time lag was found between drought indices and streamflow in the Volta River Basin. Results of this study may guide policymakers in planning how to minimize the negative impacts of future climate change that could have consequences on agriculture, water resources and energy supply. KW - Drought indices KW - Water management KW - Climate change KW - Streamfiow KW - Volta Basin Y1 - 2017 U6 - https://doi.org/10.1016/j.gloplacha.2017.07.003 SN - 0921-8181 SN - 1872-6364 VL - 155 SP - 121 EP - 132 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Norris, Jesse A1 - Carvalho, Leila M. V. A1 - Jones, Charles A1 - Cannon, Forest A1 - Bookhagen, Bodo A1 - Palazzi, Elisa A1 - Tahir, Adnan Ahmad T1 - The spatiotemporal variability of precipitation over the Himalaya: evaluation of one-year WRF model simulation JF - Climate dynamics : observational, theoretical and computational research on the climate system N2 - The Weather Research and Forecasting (WRF) model is used to simulate the spatiotemporal distribution of precipitation over central Asia over the year April 2005 through March 2006. Experiments are performed at 6.7 km horizontal grid spacing, with an emphasis on winter and summer precipitation over the Himalaya. The model and the Tropical Rainfall Measuring Mission show a similar inter-seasonal cycle of precipitation, from extratropical cyclones to monsoon precipitation, with agreement also in the diurnal cycle of monsoon precipitation. In winter months, WRF compares better in timeseries of daily precipitation to stations below than above 3-km elevation, likely due to inferior measurement of snow than rain by the stations, highlighting the need for reliable snowfall measurements at high elevations in winter. In summer months, the nocturnal precipitation cycle in the foothills and valleys of the Himalaya is captured by this 6.7-km WRF simulation, while coarser simulations with convective parameterization show near zero nocturnal precipitation. In winter months, higher resolution is less important, serving only to slightly increase precipitation magnitudes due to steeper slopes. However, even in the 6.7-km simulation, afternoon precipitation is overestimated at high elevations, which can be reduced by even higher-resolution (2.2-km) simulations. These results indicate that WRF provides skillful simulations of precipitation relevant for studies of water resources over the complex terrain in the Himalaya. KW - WRF KW - Himalayas KW - Mesoscale KW - Precipitation KW - Climate change KW - Orographicprecipitation KW - Water resources Y1 - 2017 U6 - https://doi.org/10.1007/s00382-016-3414-y SN - 0930-7575 SN - 1432-0894 VL - 49 SP - 2179 EP - 2204 PB - Springer CY - New York ER - TY - JOUR A1 - Nord, Guillaume A1 - Boudevillain, Brice A1 - Berne, Alexis A1 - Branger, Flora A1 - Braud, Isabelle A1 - Dramais, Guillaume A1 - Gerard, Simon A1 - Le Coz, Jerome A1 - Legout, Cedric A1 - Molinie, Gilles A1 - Van Baelen, Joel A1 - Vandervaere, Jean-Pierre A1 - Andrieu, Julien A1 - Aubert, Coralie A1 - Calianno, Martin A1 - Delrieu, Guy A1 - Grazioli, Jacopo A1 - Hachani, Sahar A1 - Horner, Ivan A1 - Huza, Jessica A1 - Le Boursicaud, Raphael A1 - Raupach, Timothy H. A1 - Teuling, Adriaan J. A1 - Uber, Magdalena A1 - Vincendon, Beatrice A1 - Wijbrans, Annette T1 - A high space-time resolution dataset linking meteorological forcing and hydro-sedimentary response in a mesoscale Mediterranean catchment (Auzon) of the Ardeche region, France JF - Earth System Science Data N2 - A comprehensive hydrometeorological dataset is presented spanning the period 1 January 201131 December 2014 to improve the understanding of the hydrological processes leading to flash floods and the relation between rainfall, runoff, erosion and sediment transport in a mesoscale catchment (Auzon, 116 km(2)) of the Mediterranean region. Badlands are present in the Auzon catchment and well connected to high-gradient channels of bedrock rivers which promotes the transfer of suspended solids downstream. The number of observed variables, the various sensors involved (both in situ and remote) and the space-time resolution (similar to km(2), similar to min) of this comprehensive dataset make it a unique contribution to research communities focused on hydrometeorology, surface hydrology and erosion. Given that rainfall is highly variable in space and time in this region, the observation system enables assessment of the hydrological response to rainfall fields. Indeed, (i) rainfall data are provided by rain gauges (both a research network of 21 rain gauges with a 5 min time step and an operational network of 10 rain gauges with a 5 min or 1 h time step), S-band Doppler dual-polarization radars (1 km(2), 5 min resolution), disdrometers (16 sensors working at 30 s or 1 min time step) and Micro Rain Radars (5 sensors, 100m height resolution). Additionally, during the special observation period (SOP-1) of the HyMeX (Hydrological Cycle in the Mediterranean Experiment) project, two X-band radars provided precipitation measurements at very fine spatial and temporal scales (1 ha, 5 min). (ii) Other meteorological data are taken from the operational surface weather observation stations of Meteo-France (including 2m air temperature, atmospheric pressure, 2 m relative humidity, 10m wind speed and direction, global radiation) at the hourly time resolution (six stations in the region of interest). (iii) The monitoring of surface hydrology and suspended sediment is multi-scale and based on nested catchments. Three hydrometric stations estimate water discharge at a 2-10 min time resolution. Two of these stations also measure additional physico-chemical variables (turbidity, temperature, conductivity) and water samples are collected automatically during floods, allowing further geochemical characterization of water and suspended solids. Two experimental plots monitor overland flow and erosion at 1 min time resolution on a hillslope with vineyard. A network of 11 sensors installed in the intermittent hydrographic network continuously measures water level and water temperature in headwater subcatchments (from 0.17 to 116 km(2)) at a time resolution of 2-5 min. A network of soil moisture sensors enables the continuous measurement of soil volumetric water content at 20 min time resolution at 9 sites. Additionally, concomitant observations (soil moisture measurements and stream gauging) were performed during floods between 2012 and 2014. Finally, this dataset is considered appropriate for understanding the rainfall variability in time and space at fine scales, improving areal rainfall estimations and progressing in distributed hydrological and erosion modelling. Y1 - 2017 U6 - https://doi.org/10.5194/essd-9-221-2017 SN - 1866-3508 SN - 1866-3516 VL - 9 PB - Copernicus CY - Göttingen ER - TY - JOUR A1 - Nooshiri, Nima A1 - Saul, Joachim A1 - Heimann, Sebastian A1 - Tilmann, Frederik A1 - Dahm, Torsten T1 - Revision of earthquake hypocentre locations in global bulletin data sets using source-specific station terms JF - Geophysical journal international N2 - Global earthquake locations are often associated with very large systematic travel-time residuals even for clear arrivals, especially for regional and near-regional stations in subduction zones because of their strongly heterogeneous velocity structure. Travel-time corrections can drastically reduce travel-time residuals at regional stations and, in consequence, improve the relative location accuracy. We have extended the shrinking-box source-specific station terms technique to regional and teleseismic distances and adopted the algorithm for probabilistic, nonlinear, global-search location. We evaluated the potential of the method to compute precise relative hypocentre locations on a global scale. The method has been applied to two specific test regions using existing P- and pP-phase picks. The first data set consists of 3103 events along the Chilean margin and the second one comprises 1680 earthquakes in the Tonga-Fiji subduction zone. Pick data were obtained from the GEOFON earthquake bulletin, produced using data from all available, global station networks. A set of timing corrections varying as a function of source position was calculated for each seismic station. In this way, we could correct the systematic errors introduced into the locations by the inaccuracies in the assumed velocity structure without explicitly solving for a velocity model. Residual statistics show that the median absolute deviation of the travel-time residuals is reduced by 40-60 per cent at regional distances, where the velocity anomalies are strong. Moreover, the spread of the travel-time residuals decreased by similar to 20 per cent at teleseismic distances (>28 degrees). Furthermore, strong variations in initial residuals as a function of recording distance are smoothed out in the final residuals. The relocated catalogues exhibit less scattered locations in depth and sharper images of the seismicity associated with the subducting slabs. Comparison with a high-resolution local catalogue reveals that our relocation process significantly improves the hypocentre locations compared to standard locations. KW - Seismicity and tectonics KW - Computational seismology KW - Subduction zone processes KW - Pacific Ocean KW - South America Y1 - 2016 U6 - https://doi.org/10.1093/gji/ggw405 SN - 0956-540X SN - 1365-246X VL - 208 IS - 2 SP - 589 EP - 602 PB - Oxford Univ. Press CY - Oxford ER - TY - JOUR A1 - Nitze, Ingmar A1 - Grosse, Guido A1 - Jones, Benjamin M. A1 - Arp, Christopher D. A1 - Ulrich, Mathias A1 - Fedorov, Alexander A1 - Veremeeva, Alexandra T1 - Landsat-Based Trend Analysis of Lake Dynamics across Northern Permafrost Regions JF - Remote sensing N2 - Lakes are a ubiquitous landscape feature in northern permafrost regions. They have a strong impact on carbon, energy and water fluxes and can be quite responsive to climate change. The monitoring of lake change in northern high latitudes, at a sufficiently accurate spatial and temporal resolution, is crucial for understanding the underlying processes driving lake change. To date, lake change studies in permafrost regions were based on a variety of different sources, image acquisition periods and single snapshots, and localized analysis, which hinders the comparison of different regions. Here, we present a methodology based on machine-learning based classification of robust trends of multi-spectral indices of Landsat data (TM, ETM+, OLI) and object-based lake detection, to analyze and compare the individual, local and regional lake dynamics of four different study sites (Alaska North Slope, Western Alaska, Central Yakutia, Kolyma Lowland) in the northern permafrost zone from 1999 to 2014. Regional patterns of lake area change on the Alaska North Slope (-0.69%), Western Alaska (-2.82%), and Kolyma Lowland (-0.51%) largely include increases due to thermokarst lake expansion, but more dominant lake area losses due to catastrophic lake drainage events. In contrast, Central Yakutia showed a remarkable increase in lake area of 48.48%, likely resulting from warmer and wetter climate conditions over the latter half of the study period. Within all study regions, variability in lake dynamics was associated with differences in permafrost characteristics, landscape position (i.e., upland vs. lowland), and surface geology. With the global availability of Landsat data and a consistent methodology for processing the input data derived from robust trends of multi-spectral indices, we demonstrate a transferability, scalability and consistency of lake change analysis within the northern permafrost region. KW - lake dynamics KW - lake change KW - permafrost region KW - Landsat KW - Alaska KW - Siberia KW - thermokarst KW - trend analysis KW - machine-learning Y1 - 2017 U6 - https://doi.org/10.3390/rs9070640 SN - 2072-4292 VL - 9 PB - MDPI CY - Basel ER - TY - JOUR A1 - Nied, Manuela A1 - Schröter, Kai A1 - Lüdtke, Stefan A1 - Nguyen, Viet Dung A1 - Merz, Bruno T1 - What are the hydro-meteorological controls on flood characteristics? JF - Journal of hydrology N2 - Flood events can be expressed by a variety of characteristics such as flood magnitude and extent, event duration or incurred loss. Flood estimation and management may benefit from understanding how the different flood characteristics relate to the hydrological catchment conditions preceding the event and to the meteorological conditions throughout the event. In this study, we therefore propose a methodology to investigate the hydro-meteorological controls on different flood characteristics, based on the simulation of the complete flood risk chain from the flood triggering precipitation event, through runoff generation in the catchment, flood routing and possible inundation in the river system and floodplains to flood loss. Conditional cumulative distribution functions and regression tree analysis delineate the seasonal varying flood processes and indicate that the effect of the hydrological pre-conditions, i.e. soil moisture patterns, and of the meteorological conditions, i.e. weather patterns, depends on the considered flood characteristic. The methodology is exemplified for the Elbe catchment. In this catchment, the length of the build-up period, the event duration and the number of gauges undergoing at least a 10-year flood are governed by weather patterns. The affected length and the number of gauges undergoing at least a 2-year flood are however governed by soil moisture patterns. In case of flood severity and loss, the controlling factor is less pronounced. Severity is slightly governed by soil moisture patterns whereas loss is slightly governed by weather patterns. The study highlights that flood magnitude and extent arise from different flood generation processes and concludes that soil moisture patterns as well as weather patterns are not only beneficial to inform on possible flood occurrence but also on the involved flood processes and resulting flood characteristics. KW - Flood KW - Flood duration KW - Flood magnitude KW - Flood loss KW - Soil moisture patterns KW - Antecedent conditions KW - Weather patterns KW - Large basins Y1 - 2017 U6 - https://doi.org/10.1016/j.jhydrol.2016.12.003 SN - 0022-1694 SN - 1879-2707 VL - 545 SP - 310 EP - 326 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Nelson, Daniel B. A1 - Knohl, Alexander A1 - Sachse, Dirk A1 - Schefulss, Enno A1 - Kahmen, Ansgar T1 - Sources and abundances of leaf waxes in aerosols in central Europe JF - Geochimica et cosmochimica acta : journal of the Geochemical Society and the Meteoritical Society N2 - Atmospheric transport is an understudied mechanism for leaf wax hydrogen isotope applications that contributes to mobilizing and depositing these compounds on the surface of the Earth. While previous efforts have identified the importance of atmospheric leaf wax deposition in remote marine locations, the processes are not well constrained on land in temperate latitudes where lakes are common and sedimentary leaf wax hydrogen isotope values are an attractive tool for understanding past precipitation changes. This work presents results from a field study that was conducted in 2010 and 2011 at Hainich National Park, Germany in order to evaluate the quantity and sources of leaf waxes in the atmosphere. Aerosols were sampled at approximately weekly intervals inside the forest canopy, and n-alkane distributions and hydrogen isotope values were compared with those from major tree species surrounding the sampling site. Despite sampling in what was expected to be a major production center, the distribution and hydrogen isotope values of atmospheric n-alkanes bore little resemblance to those of the local vegetation. Comparison with local meteorological data and to 10-day and 36-h back air mass trajectories indicated shifting effects of winds and temperature, and that mesoscale transport processes were more important than longrange mechanisms. Back trajectories also highlighted source effects, with easterly winds coinciding with relatively lower leaf wax hydrogen isotope values from more continental regions. These results suggest that leaf wax aerosols average over spatial scales that exceed typical surface catchment areas for small lake systems, even in forested areas, yet that the area over which these compounds are derived is still relatively regional. Depositional fluxes were also estimated in order to assess the potential importance of atmospheric transport to sedimentary archives. Although difficult to constrain, these estimates suggest that atmospheric deposition may be non-negligible for lake systems in cases where inputs from rivers or surface runoff are limited. Together, these observations provide new insights on how leaf waxes from different sources are integrated during aeolian transport and the spatial scales over which these processes occur. KW - Hydrogen isotopes KW - Leaf wax KW - Aerosols KW - n-Alkanes KW - Biomarkers KW - Lakes KW - Sediments Y1 - 2016 U6 - https://doi.org/10.1016/j.gca.2016.11.018 SN - 0016-7037 SN - 1872-9533 VL - 198 SP - 299 EP - 314 PB - Elsevier CY - Oxford ER - TY - JOUR A1 - Neill, Christopher A1 - Jankowski, KathiJo A1 - Brando, Paulo M. A1 - Coe, Michael T. A1 - Deegan, Linda A. A1 - Macedo, Marcia N. A1 - Riskin, Shelby H. A1 - Porder, Stephen A1 - Elsenbeer, Helmut A1 - Krusche, Alex V. T1 - Surprisingly Modest Water Quality Impacts From Expansion and Intensification of Large-Sscale Commercial Agriculture in the Brazilian Amazon-Cerrado Region JF - Tropical conservation science N2 - Large-scale commercial cropping of soybeans expanded in the tropical Amazon and Cerrado biomes of Brazil after 1990. More recently, cropping intensified from single-cropping of soybeans to double-cropping of soybeans with corn or cotton. Cropland expansion and intensification, and the accompanying use of mineral fertilizers, raise concerns about whether nutrient runoff and impacts to surface waters will be similar to those experienced in commercial cropland regions at temperate latitudes. We quantified water infiltration through soils, water yield, and streamwater chemistry in watersheds draining native tropical forest and single-and double-cropped areas on the level, deep, highly weathered soils where cropland expansion and intensification typically occurs. Although water yield increased four-fold from croplands, streamwater chemistry remained largely unchanged. Soil characteristics exerted important control over the movement of nitrogen (N) and phosphorus (P) into streams. High soil infiltration rates prevented surface erosion and movement of particulate P, while P fixation in surface soils restricted P movement to deeper soil layers. Nitrogen retention in deep soils, likely by anion exchange, also appeared to limit N leaching and export in streamwater from both single-and double-cropped watersheds that received nitrogen fertilizer. These mechanisms led to lower streamwater P and N concentrations and lower watershed N and P export than would be expected, based on studies from temperate croplands with similar cropping and fertilizer application practices. KW - water KW - quality KW - agriculture KW - intensification KW - impact Y1 - 2017 U6 - https://doi.org/10.1177/1940082917720669 SN - 1940-0829 VL - 10 PB - Sage Publ. CY - Thousand Oaks ER - TY - JOUR A1 - Negi, Sanjay S. A1 - Paul, Ajay A1 - Cesca, Simone A1 - Kamal, A1 - Kriegerowski, Marius A1 - Mahesh, P. A1 - Gupta, Sandeep T1 - Crustal velocity structure and earthquake processes of Garhwal-Kumaun Himalaya: Constraints from regional waveform inversion and array beam modeling JF - Tectonophysics : international journal of geotectonics and the geology and physics of the interior of the earth N2 - In order to understand present day earthquake kinematics at the Indian plate boundary, we analyse seismic broadband data recorded between 2007 and 2015 by the regional network in the Garhwal-Kumaun region, northwest Himalaya. We first estimate a local 1-D velocity model for the computation of reliable Green's functions, based on 2837 P-wave and 2680 S-wave arrivals from 251 well located earthquakes. The resulting 1-D crustal structure yields a 4-layer velocity model down to the depths of 20 km. A fifth homogeneous layer extends down to 46 km, constraining the Moho using travel-time distance curve method. We then employ a multistep moment tensor (MT) inversion algorithm to infer seismic moment tensors of 11 moderate earthquakes with Mw magnitude in the range 4.0–5.0. The method provides a fast MT inversion for future monitoring of local seismicity, since Green's functions database has been prepared. To further support the moment tensor solutions, we additionally model P phase beams at seismic arrays at teleseismic distances. The MT inversion result reveals the presence of dominant thrust fault kinematics persisting along the Himalayan belt. Shallow low and high angle thrust faulting is the dominating mechanism in the Garhwal-Kumaun Himalaya. The centroid depths for these moderate earthquakes are shallow between 1 and 12 km. The beam modeling result confirm hypocentral depth estimates between 1 and 7 km. The updated seismicity, constrained source mechanism and depth results indicate typical setting of duplexes above the mid crustal ramp where slip is confirmed along out-of-sequence thrusting. The involvement of Tons thrust sheet in out-of-sequence thrusting indicate Tons thrust to be the principal active thrust at shallow depth in the Himalayan region. Our results thus support the critical taper wedge theory, where we infer the microseismicity cluster as a result of intense activity within the Lesser Himalayan Duplex (LHD) system. KW - Critical taper wedge KW - Lesser Himalayan Duplex KW - Out-of-sequence thrust Y1 - 2017 U6 - https://doi.org/10.1016/j.tecto.2017.05.007 SN - 0040-1951 SN - 1879-3266 VL - 712 SP - 45 EP - 63 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Neely, Alexander B. A1 - Bookhagen, Bodo A1 - Burbank, Douglas W. T1 - An automated knickzone selection algorithm (KZ-Picker) to analyze transient landscapes: Calibration and validation JF - Journal of geophysical research : Earth surface N2 - Streams commonly respond to base-level fall by localizing erosion within steepened, convex knickzone reaches. Localized incision causes knickzone reaches to migrate upstream. Such migrating knickzones dictate the pace of landscape response to changes in tectonics or erosional efficiency and can help quantify the timing and source of base-level fall. Identification of knickzones typically requires individual selection of steepened reaches: a process that is tedious and subjective and has no efficient means to measure knickzone size. We construct an algorithm to automate this procedure by selecting the bounds of knickzone reaches in a -space (drainage-area normalized) framework. An automated feature calibrates algorithm parameters to a subset of knickzones handpicked by the user. The algorithm uses these parameters as consistent criteria to identify knickzones objectively, and then the algorithm measures the height, length, and slope of each knickzone reach. We test the algorithm on 1, 10, and 30m resolution digital elevation models (DEMs) of six catchments (trunk-stream lengths: 2.1-5.4km) on Santa Cruz Island, southern California. On the 1m DEM, algorithm-selected knickzones confirm 93% of handpicked knickzone positions (n=178) to a spatial accuracy of 100m, 88% to an accuracy within 50m, and 46% to an accuracy within 10m. Using 10 and 30m DEMs, accuracy is similar: 88-86% to 100m and 82% to 50m (n=38 and 36, respectively). The algorithm enables efficient regional comparison of the size and location of knickzones with geologic structures, mapped landforms, and hillslope morphology, thereby facilitating approaches to characterize the dynamics of transient landscapes. Plain Language Summary The shape of rivers reflects the environments that they flow through and the environments that they link together: mountains and oceans. Anywhere along the length of a river, changes in environmental conditions are propagated upstream and downstream as the river changes its morphology to match the new environmental conditions. Commonly, rivers steepen as land uplifts faster in regions of high tectonic convergence. The steepening of river gradients is propagated upstream and can be mapped to trace zones of high tectonic activity across landscapes and estimate the source and timing of environmental change. Such insights may indicate regions where earthquakes have become more frequent in the recent past and how rivers respond to these changes. In this submission, we detail an algorithm that can use digital topographic data (similar to google earth), to automatically map and measure anomalously steep river reaches across continental scales. This technology can highlight areas that have experienced recent sustained changes in environmental conditions, evident by changes in the morphology of rivers. Such environmental conditions could be changes in tectonic uplift and earthquake activity, changes in sea level, changes in land-use, or changes in climate, all factors that can produce measurable differences in river morphology over time. KW - knickpoint KW - transient KW - knickzone KW - incision KW - relict landscape KW - Santa Cruz Island Y1 - 2017 U6 - https://doi.org/10.1002/2017JF004250 SN - 2169-9003 SN - 2169-9011 VL - 122 SP - 1236 EP - 1261 PB - American Geophysical Union CY - Washington ER - TY - JOUR A1 - Neelmeijer, Julia A1 - Motagh, Mandi A1 - Bookhagen, Bodo T1 - High-resolution digital elevation models from single-pass TanDEM-X interferometry over mountainous regions: A case study of Inylchek Glacier, Central Asia JF - ISPRS journal of photogrammetry and remote sensing : official publication of the International Society for Photogrammetry and Remote Sensing N2 - This study demonstrates the potential of using single-pass TanDEM-X (TDX) radar imagery to analyse inter- and intra-annual glacier changes in mountainous terrain. Based on SAR images acquired in February 2012, March 2013 and November 2013 over the Inylchek Glacier, Kyrgyzstan, we discuss in detail the processing steps required to generate three reliable digital elevation models (DEMs) with a spatial resolution of 10 m that can be used for glacial mass balance studies. We describe the interferometric processing steps and the influence of a priori elevation information that is required to model long wavelength topographic effects. We also focus on DEM alignment to allow optimal DEM comparisons and on the effects of radar signal penetration on ice and snow surface elevations. We finally compare glacier elevation changes between the three TDX DEMs and the C-band shuttle radar topography mission (SRTM) DEM from February 2000. We introduce a new approach for glacier elevation change calculations that depends on the elevation and slope of the terrain. We highlight the superior quality of the TDX DEMs compared to the SRTM DEM, describe remaining DEM uncertainties and discuss the limitations that arise due to the side-looking nature of the radar sensor. (C) 2017 International Society for Photogrammetry and Remote Sensing, Inc. (ISPRS). Published by Elsevier B.V. All rights reserved. KW - TanDEM-X KW - InSAR KW - DEM generation KW - Inter-annual glacier elevation change KW - Inylchek Glacier Y1 - 2017 U6 - https://doi.org/10.1016/j.isprsjprs.2017.05.011 SN - 0924-2716 SN - 1872-8235 VL - 130 SP - 108 EP - 121 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Nazarova, Larisa B. A1 - Grebennikova, Tatiana A. A1 - Razjigaeva, Nadezhda G. A1 - Ganzey, Larisa A. A1 - Belyanina, Nina I. A1 - Arslanov, Khikmat A. A1 - Kaistrenko, Victor M. A1 - Gorbunov, Aleksey O. A1 - Kharlamov, Andrey A. A1 - Rudaya, Natalia A1 - Palagushkina, Olga A1 - Biskaborn, Boris A1 - Diekmann, Bernhard T1 - Reconstruction of Holocene environmental changes in Southern Kurils (North-Western Pacific) based on palaeolake sediment proxies from Shikotan Island JF - Global and planetary change N2 - We investigated a well-dated sediment section of a palaeolake situated in the coastal zone of Shikotan Island (Lesser Kurils) for organic sediment-geochemistry and biotic components (diatoms, chironomids, pollen) in order to provide a reconstruction of the palaeoenvironmental changes and palaeo-events (tsunamis, sea-level fluctuations and landslides) in Holocene. During the ca 8000 years of sedimentation the changes in organic sediment-geochemistry and in composition of the diatoms and chironomids as well as the shifts in composition of terrestrial vegetation suggest that the period until ca 5800 cal yr BP was characterized by a warm and humid climate (corresponds to middle Holocene optimum) with climate cooling thereafter. A warm period reconstructed from ca 900 to at least ca 580 cal yr BP corresponds to a transition to a Nara-Heian-Kamakura warm stage and can be correlated to a Medieval Warm Period. After 580 cal yr PB, the lake gradually dried out and climatic signals could not be obtained from the declining lacustrine biological communities, but the increasing role of spruce and disappearance of the oak from the vegetation give evidences of the climate cooling that can be correlated with the LIA. The marine regression stages at the investigated site are identified for ca 6200-5900 (at the end of the middle Holocene transgression), ca 5500-5100 (Middle Jomon regression or Kemigawa regression), and ca 1070-360 cal yr BP (at the end of Heian transgression). The lithological structure of sediments and the diatom compositions give evidences for the multiple tsunami events of different strengths in the Island. Most remarkable of them can be dated at around ca 7000, 6460, 5750, 4800, 950 cal yr BP. The new results help to understand the Holocene environmental history of the Southern Kurils as a part of the Kuril-Kamchatka and Aleutian Marginal Sea-Island Arc Systems in the North-Western Pacific region. KW - Kurils KW - North-Western Pacific KW - Palaeoclimate KW - Sea level KW - Diatoms KW - Chironomids KW - Pollen Y1 - 2017 U6 - https://doi.org/10.1016/j.gloplacha.2017.10.005 SN - 0921-8181 SN - 1872-6364 VL - 159 SP - 25 EP - 36 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Nazarova, Larisa B. A1 - Bleibtreu, Annette A1 - Hoff, Ulrike A1 - Dirksen, Veronika A1 - Diekmann, Bernhard T1 - Changes in temperature and water depth of a small mountain lake during the past 3000 years in Central Kamchatka reflected by a chironomid record JF - Quaternary international : the journal of the International Union for Quaternary Research N2 - We investigated chironomid assemblages of a well-dated sediment core from a small seepage lake situated at the eastern slope of the Central Kamchatka Mountain Chain, Far East Russia. The chironomid fauna of the investigated Sigrid Lake is dominated by littoral taxa that are sensitive to fluctuations of the water level. Two groups of taxa interchangeably dominate the record responding to the changes in the lake environment during the past 2800 years. The first group of littoral phytophilic taxa includes Psectrocladius sordidellus-type, Corynoneura arctica-type and Dicrotendipes nervosus-type. The abundances of the taxa from this group have the strongest influence on the variations of PCA 1, and these taxa mostly correspond to low water levels, moderate temperatures and slightly acidified conditions. The second group of taxa includes Microtendipes pedellus-type, Tanytarsus lugens-type, and Tanytarsus pallidicornistype. The variations in the abundances of these taxa, and especially of M. pedellus-type, are in accordance with PCA 2 and correspond to the higher water level in the lake, more oligotrophic and neutral pH conditions. Water depths (WD) were reconstructed, using a modern chironomid-based temperature and water depth calibration data set (training set) and inference model from East Siberia (Nazarova et al., 2011). Mean July air temperatures (T July) were inferred using a chironomid-based temperature inference model based on a modern calibration data set for the Far East (Nazarova et al., 2015). The application of transfer functions resulted in reconstructed T July fluctuations of approximately 3 degrees C over the last 2800 years. Low temperatures (11.0-12.0 degrees C) were reconstructed for the periods between ca 1700 and 1500 cal yr BP (corresponding to the Kofun cold stage) and between ca 1200 and 150 cal yr BP (partly corresponding to the Little Ice Age [LIA]). Warm periods (modern T July or higher) were reconstructed for the periods between ca 2700 and 1800 cal yr BP, 1500 and 1300 cal yr BP and after 150 cal yr BP. WD reconstruction revealed that the lake level was lower than its present level at the beginning of the record between ca 2600 and 2300 cal yr BP and ca 550 cal yr BP. Between ca 2300 and 700 cal yr BP as well as between 450 and 150 cal yr BP, the lake level was higher than it is today, most probably reflecting more humid conditions. (C) 2016 Elsevier Ltd and INQUA. All rights reserved. KW - Kamchatka KW - Chironomids KW - Palaeoclimate KW - Late Holocene KW - Temperature KW - Water depth Y1 - 2017 U6 - https://doi.org/10.1016/j.quaint.2016.10.008 SN - 1040-6182 SN - 1873-4553 VL - 447 SP - 46 EP - 58 PB - Elsevier CY - Oxford ER - TY - JOUR A1 - Müller, Christina Magdalena A1 - Huwe, Björn A1 - Wissemann, Volker A1 - Joshi, Jasmin Radha A1 - Gemeinholzer, Birgit T1 - Conservation genetic assessment of four plant species in a small replica of a steppe ecosystem >30 years after establishment JF - Biodiversity and conservation KW - Ex situ/in situ population genetic comparison KW - ISSR KW - Conservation genetics KW - Sand dune steppe and grassland vegetation KW - Botanic gardens Y1 - 2017 U6 - https://doi.org/10.1007/s10531-017-1381-1 SN - 0960-3115 SN - 1572-9710 VL - 26 SP - 2699 EP - 2716 PB - Springer CY - Dordrecht ER - TY - JOUR A1 - Musolff, Andreas A1 - Selle, Benny A1 - Buttner, Olaf A1 - Opitz, Michael A1 - Tittel, Jörg T1 - Unexpected release of phosphate and organic carbon to streams linked to declining nitrogen depositions JF - Global change biology N2 - Reductions in emissions have successfully led to a regional decline in atmospheric nitrogen depositions over the past 20 years. By analyzing long-term data from 110 mountainous streams draining into German drinking water reservoirs, nitrate concentrations indeed declined in the majority of catchments. Furthermore, our meta-analysis indicates that the declining nitrate levels are linked to the release of dissolved iron to streams likely due to a reductive dissolution of iron(III) minerals in riparian wetland soils. This dissolution process mobilized adsorbed compounds, such as phosphate, dissolved organic carbon and arsenic, resulting in concentration increases in the streams and higher inputs to receiving drinking water reservoirs. Reductive mobilization was most significant in catchments with stream nitrate concentrations < 6 mg L-1. Here, nitrate, as a competing electron acceptor, was too low in concentration to inhibit microbial iron(III) reduction. Consequently, observed trends were strongest in forested catchments, where nitrate concentrations were unaffected by agricultural and urban sources and which were therefore sensitive to reductions of atmospheric nitrogen depositions. We conclude that there is strong evidence that the decline in nitrogen deposition toward pre-industrial conditions lowers the redox buffer in riparian soils, destabilizing formerly fixed problematic compounds, and results in serious implications for water quality. KW - atmospheric deposition KW - carbon cycle KW - nitrogen biogeochemistry KW - organic matter KW - riparian zone KW - streamwater chemistry Y1 - 2017 U6 - https://doi.org/10.1111/gcb.13498 SN - 1354-1013 SN - 1365-2486 VL - 23 SP - 1891 EP - 1901 PB - Wiley CY - Hoboken ER - TY - JOUR A1 - Munz, Matthias A1 - Schmidt, Christian T1 - Estimation of vertical water fluxes from temperature time series by the inverse numerical computer program FLUX-BOT JF - Hydrological processes N2 - The application of heat as a hydrological tracer has become a standard method for quantifying water fluxes between groundwater and surface water. The typical application is to estimate vertical water fluxes in the shallow subsurface beneath streams or lakes. For this purpose, time series of temperatures in the surface water and in the sediment are measured and evaluated by a vertical 1D representation of heat transport by advection and conduction. Several analytical solutions exist to calculate the vertical water flux from the measured temperatures. Although analytical solutions can be easily implemented, they are restricted to specific boundary conditions such as a sinusoidal upper temperature boundary. Numerical solutions offer higher flexibility in the selection of the boundary conditions. This, in turn, reduces the effort of data preprocessing, such as the extraction of the diurnal temperature variation from the raw data. Here, we present software to estimate water fluxes based on temperaturesFLUX-BOT. FLUX-BOT is a numerical code written in MATLAB that calculates vertical water fluxes in saturated sediments based on the inversion of measured temperature time series observed at multiple depths. FLUX-BOT applies a centred Crank-Nicolson implicit finite difference scheme to solve the one-dimensional heat advection-conduction equation. FLUX-BOT includes functions for the inverse numerical routines, functions for visualizing the results, and a function for performing uncertainty analysis. We present applications of FLUX-BOT to synthetic and to real temperature data to demonstrate its performance. KW - heat tracing KW - numerical solution KW - surface water groundwater interaction KW - temperature time series KW - vertical water flux Y1 - 2017 U6 - https://doi.org/10.1002/hyp.11198 SN - 0885-6087 SN - 1099-1085 VL - 31 SP - 2713 EP - 2724 PB - Wiley CY - Hoboken ER - TY - JOUR A1 - Munz, Matthias A1 - Oswald, Sascha A1 - Schmidt, Christian T1 - Coupled Long-Term Simulation of Reach-Scale Water and Heat Fluxes Across the River-Groundwater Interface for Retrieving Hyporheic Residence Times and Temperature Dynamics JF - Water resources research N2 - Flow patterns in conjunction with seasonal and diurnal temperature variations control ecological and biogeochemical conditions in hyporheic sediments. In particular, hyporheic temperatures have a great impact on many temperature-sensitive microbial processes. In this study, we used 3-D coupled water flow and heat transport simulations applying the HydroGeoSphere code in combination with high-resolution observations of hydraulic heads and temperatures to quantify reach-scale water and heat flux across the river-groundwater interface and hyporheic temperature dynamics of a lowland gravel bed river. The model was calibrated in order to constrain estimates of the most sensitive model parameters. The magnitude and variations of the simulated temperatures matched the observed ones, with an average mean absolute error of 0.7 degrees C and an average Nash Sutcliffe efficiency of 0.87. Our results indicate that nonsubmerged streambed structures such as gravel bars cause substantial thermal heterogeneity within the saturated sediment at the reach scale. Individual hyporheic flow path temperatures strongly depend on the flow path residence time, flow path depth, river, and groundwater temperature. Variations in individual hyporheic flow path temperatures were up to 7.9 degrees C, significantly higher than the daily average (2.8 degrees C), but still lower than the average seasonal hyporheic temperature difference (19.2 degrees C). The distribution between flow path temperatures and residence times follows a power law relationship with exponent of about 0.37. Based on this empirical relation, we further estimated the influence of hyporheic flow path residence time and temperature on oxygen consumption which was found to partly increase by up to 29% in simulations. Y1 - 2017 U6 - https://doi.org/10.1002/2017WR020667 SN - 0043-1397 SN - 1944-7973 VL - 53 SP - 8900 EP - 8924 PB - American Geophysical Union CY - Washington ER - TY - JOUR A1 - Morandi, Bertrand A1 - Kail, Jochem A1 - Tödter, Anne A1 - Wolter, Christian A1 - Piegay, Herve T1 - Diverse Approaches to Implement and Monitor River Restoration BT - a Comparative Perspective in France and Germany JF - Environmental Management N2 - River restoration is a main emphasis of river management in European countries. Cross-national comparisons of its implementation are still rare in scientific literature. Based on French and German national censuses, this study compares river restoration practices and monitoring by analysing 102 French and 270 German projects. This comparison aims to draw a spatial and temporal framework of restoration practices in both countries to identify potential drivers of cross-national similarities and differences. The results underline four major trends: (1) a lag of almost 15 years in river restoration implementation between France and Germany, with a consequently higher share of projects in Germany than in France, (2) substantial similarities in restored reach characteristics, short reach length, small rivers, and in "agricultural" areas, (3) good correspondences between stressors identified and restoration measures implemented. Morphological alterations were the most important highlighted stressors. River morphology enhancement, especially instream enhancements, were the most frequently implemented restoration measures. Some differences exist in specific restoration practices, as river continuity restoration were most frequently implemented in French projects, while large wood introduction or channel re-braiding were most frequently implemented in German projects, and (4) some quantitative and qualitative differences in monitoring practices and a significant lack of project monitoring, especially in Germany compared to France. These similarities and differences between Germany and France in restoration application and monitoring possibly result from a complex set of drivers that might be difficult to untangle (e.g., environmental, technical, political, cultural). KW - River restoration KW - Project monitoring KW - Hydromorphologic alteration KW - Mitigation measures KW - France KW - Germany Y1 - 2017 U6 - https://doi.org/10.1007/s00267-017-0923-3 SN - 0364-152X SN - 1432-1009 VL - 60 SP - 931 EP - 946 PB - Springer CY - New York ER - TY - JOUR A1 - Molnos, Sonja A1 - Mamdouh, Tarek A1 - Petri, Stefan A1 - Nocke, Thomas A1 - Weinkauf, Tino A1 - Coumou, Dim T1 - A network-based detection scheme for the jet stream core JF - Earth system dynamics N2 - The polar and subtropical jet streams are strong upper-level winds with a crucial influence on weather throughout the Northern Hemisphere midlatitudes. In particular, the polar jet is located between cold arctic air to the north and warmer subtropical air to the south. Strongly meandering states therefore often lead to extreme surface weather. The parameter values of the detection scheme are optimized using simulated annealing and a skill function that accounts for the zonal-mean jet stream position (Rikus, 2015). After the successful optimization process, we apply our scheme to reanalysis data covering 1979-2015 and calculate seasonal-mean probabilistic maps and trends in wind strength and position of jet streams. We present longitudinally defined probability distributions of the positions for both jets for all on the Northern Hemisphere seasons. This shows that winter is characterized by two well-separated jets over Europe and Asia (ca. 20 degrees W to 140 degrees E). In contrast, summer normally has a single merged jet over the western hemisphere but can have both merged and separated jet states in the eastern hemisphere. Y1 - 2017 U6 - https://doi.org/10.5194/esd-8-75-2017 SN - 2190-4979 SN - 2190-4987 VL - 8 IS - 1 SP - 75 EP - 89 PB - Copernicus CY - Göttingen ER - TY - JOUR A1 - Molkenthin, Christian A1 - Scherbaum, Frank A1 - Griewank, Andreas A1 - Leovey, Hernan A1 - Kucherenko, Sergei A1 - Cotton, Fabrice T1 - Derivative-Based Global Sensitivity Analysis: Upper Bounding of Sensitivities in Seismic-Hazard Assessment Using Automatic Differentiation JF - Bulletin of the Seismological Society of America N2 - Seismic-hazard assessment is of great importance within the field of engineering seismology. Nowadays, it is common practice to define future seismic demands using probabilistic seismic-hazard analysis (PSHA). Often it is neither obvious nor transparent how PSHA responds to changes in its inputs. In addition, PSHA relies on many uncertain inputs. Sensitivity analysis (SA) is concerned with the assessment and quantification of how changes in the model inputs affect the model response and how input uncertainties influence the distribution of the model response. Sensitivity studies are challenging primarily for computational reasons; hence, the development of efficient methods is of major importance. Powerful local (deterministic) methods widely used in other fields can make SA feasible, even for complex models with a large number of inputs; for example, automatic/algorithmic differentiation (AD)-based adjoint methods. Recently developed derivative-based global sensitivity measures can combine the advantages of such local SA methods with efficient sampling strategies facilitating quantitative global sensitivity analysis (GSA) for complex models. In our study, we propose and implement exactly this combination. It allows an upper bounding of the sensitivities involved in PSHA globally and, therefore, an identification of the noninfluential and the most important uncertain inputs. To the best of our knowledge, it is the first time that derivative-based GSA measures are combined with AD in practice. In addition, we show that first-order uncertainty propagation using the delta method can give satisfactory approximations of global sensitivity measures and allow a rough characterization of the model output distribution in the case of PSHA. An illustrative example is shown for the suggested derivative-based GSA of a PSHA that uses stochastic ground-motion simulations. Y1 - 2017 U6 - https://doi.org/10.1785/0120160185 SN - 0037-1106 SN - 1943-3573 VL - 107 SP - 984 EP - 1004 PB - Seismological Society of America CY - Albany ER - TY - JOUR A1 - Mohr, Christian Heinrich A1 - Manga, Michael A1 - Wang, Chi-Yuen A1 - Korup, Oliver T1 - Regional changes in streamflow after a megathrust earthquake JF - Earth & planetary science letters N2 - Moderate to large earthquakes can increase the amount of water feeding stream flows, mobilizing excess water from deep groundwater, shallow groundwater, or the vadose zone. Here we examine the regional pattern of streamflow response to the Maule M8.8 earthquake across Chile's diverse topographic and hydro-climatic gradients. We combine streamflow analyses with groundwater flow modeling and a random forest classifier, and find that, after the earthquake, at least 85 streams had a change in flow. Discharge mostly increased () shortly after the earthquake, liberating an excess water volume of >1.1 km3, which is the largest ever reported following an earthquake. Several catchments had increased discharge of >50 mm, locally exceeding seasonal streamflow discharge under undisturbed conditions. Our modeling results favor enhanced vertical permeability induced by dynamic strain as the most probable process explaining the observed changes at the regional scale. Supporting this interpretation, our random forest classification identifies peak ground velocity and elevation extremes as most important for predicting streamflow response. Given the mean recurrence interval of ∼25 yr for >M8.0 earthquakes along the Peru–Chile Trench, our observations highlight the role of earthquakes in the regional water cycle, especially in arid environments. KW - Maule earthquake KW - streamflow response KW - permeability KW - groundwater flow modeling KW - earthquake hydrology Y1 - 2016 U6 - https://doi.org/10.1016/j.epsl.2016.11.013 SN - 0012-821X SN - 1385-013X VL - 458 SP - 418 EP - 428 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Mohr, Christian Heinrich A1 - Korup, Oliver A1 - Ulloa, Hector A1 - Iroume, Andres T1 - Pyroclastic Eruption Boosts Organic Carbon Fluxes Into Patagonian Fjords JF - Global biogeochemical cycles N2 - Fjords and old-growth forests store large amounts of organic carbon. Yet the role of episodic disturbances, particularly volcanic eruptions, in mobilizing organic carbon in fjord landscapes covered by temperate rainforests remains poorly quantified. To this end, we estimated how much wood and soils were flushed to nearby fjords following the 2008 eruption of Chaiten volcano in south-central Chile, where pyroclastic sediments covered >12km(2) of pristine temperate rainforest. Field-based surveys of forest biomass, soil organic content, and dead wood transport reveal that the reworking of pyroclastic sediments delivered similar to 66,500+14,600/-14,500tC of large wood to two rivers entering the nearby Patagonian fjords in less than a decade. A similar volume of wood remains in dead tree stands and buried beneath pyroclastic deposits (similar to 79,900+21,100/-16,900tC) or stored in active river channels (5,900-10,600tC). We estimate that bank erosion mobilized similar to 132,300(+21,700)/(-30,600)tC of floodplain forest soil. Eroded and reworked forest soils have been accreting on coastal river deltas at >5mmyr(-1) since the eruption. While much of the large wood is transported out of the fjord by long-shore drift, the finer fraction from eroded forest soils is likely to be buried in the fjords. We conclude that the organic carbon fluxes boosted by rivers adjusting to high pyroclastic sediment loads may remain elevated for up to a decade and that Patagonian temperate rainforests disturbed by excessive loads of pyroclastic debris can be episodic short-lived carbon sources. Plain Language Summary Fjords and old-growth forests are important sinks of organic carbon. However, the role of volcanic eruptions in flushing organic carbon in fjord landscapes remains unexplored. Here we estimated how much forest vegetation and soils were lost to fjords following the 2008 eruption ofunknownChaiten volcano in south-central Chile. Pyroclastic sediments obliterated near-pristine temperateunknownrainforest, and the subsequent reworking of these sediments delivered in less than a decade similar to 66,000 tC of large wood to the mountain rivers, draining into the nearby Patagonian fjords. A similar volume of wood remains in dead tree stands and buried beneath pyroclastic deposits or stored in active riverunknownchannels. We estimate that similar to 130,000 tC of organic carbon-rich soil was lost to erosion, thus adding to the carbon loads. While much of the wood enters the long-shore drift in the fjord heads, the finerunknownfraction from eroded forest soils is likely to be buried in the fjords at rates that exceed regional estimates by an order of magnitude. We anticipate that these eruption-driven fluxes will remain elevated forunknownthe coming years and that Patagonian temperate rainforests episodically switch from carbon sinks to hitherto undocumented carbon sources if disturbed by explosive volcanic eruptions. KW - Chile KW - Patagonia KW - rainforest KW - volcanic eruption KW - organic carbon KW - biomass Y1 - 2017 U6 - https://doi.org/10.1002/2017GB005647 SN - 0886-6236 SN - 1944-9224 VL - 31 SP - 1626 EP - 1638 PB - American Geophysical Union CY - Washington ER - TY - JOUR A1 - Mischke, Steffen A1 - Lai, Zhongping A1 - Aichner, Bernhard A1 - Heinecke, Liv A1 - Mahmoudov, Zafar A1 - Kuessner, Marie A1 - Herzschuh, Ulrike T1 - Radiocarbon and optically stimulated luminescence dating of sediments from Lake Karakul, Tajikistan JF - Quaternary geochronology : the international research and review journal on advances in quaternary dating techniques N2 - Lake Karakul in the eastern Pamirs is a large and closed-basin lake in a partly glaciated catchment. Two parallel sediment cores were collected from 12 m water depth. The cores were correlated using XRF analysis and dated using radiocarbon and OSL techniques. The age results of the two dating methods are generally in agreement. The correlated composite core of 12.26 m length represents continuous accumulation of sediments in the lake basin since 31 ka. The lake reservoir effect (LRE) remained relatively constant over this period. High sediment accumulation rates (SedARs) were recorded before 23 ka and after 6.5 ka. The relatively close position of the coring location near the eastern shore of the lake implies that high SedARs resulted from low lake levels. Thus, high SedARs and lower lake levels before 23 ka probably reflect cold and dry climate conditions that inhibited the arrival of moist air at high elevation in the eastern Pamirs. Low lake levels after 6.5 ka were probably caused by declining temperatures after the warmer early Holocene, which had caused a reduction in water resources stored as snow, ice and frozen ground in the catchment. Low SedARs during 23-6.5 ka suggest increased lake levels in Lake Karakul. A short-lived increase of SedARs at 15 ka probably corresponds to the rapid melting of glaciers in the Karakul catchment during the Greenland Interstadial le, shortly after glaciers in the catchment had reached their maximum extents. The sediment cores from Lake Karakul represent an important climate archive with robust chronology for the last glacial interglacial cycle from Central Asia. (C) 2017 Elsevier B.V. All rights reserved. KW - Radiocarbon and OSL dating KW - Lake sediments KW - Pamir mountains KW - Late pleistocene KW - Holocene Y1 - 2017 U6 - https://doi.org/10.1016/j.quageo.2017.05.008 SN - 1871-1014 SN - 1878-0350 VL - 41 SP - 51 EP - 61 PB - Elsevier CY - Oxford ER - TY - JOUR A1 - Milewski, Robert A1 - Chabrillat, Sabine A1 - Behling, Robert T1 - Analyses of Recent Sediment Surface Dynamic of a Namibian Kalahari Salt Pan Based on Multitemporal Landsat and Hyperspectral Hyperion Data JF - Remote Sensing N2 - This study combines spaceborne multitemporal and hyperspectral data to analyze the spatial distribution of surface evaporite minerals and changes in a semi-arid depositional environment associated with episodic flooding events, the Omongwa salt pan (Kalahari, Namibia). The dynamic of the surface crust is evaluated by a change-detection approach using the Iterative-reweighted Multivariate Alteration Detection (IR-MAD) based on the Landsat archive imagery from 1984 to 2015. The results show that the salt pan is a highly dynamic and heterogeneous landform. A change gradient is observed from very stable pan border to a highly dynamic central pan. On the basis of hyperspectral EO-1 Hyperion images, the current distribution of surface evaporite minerals is characterized using Spectral Mixture Analysis (SMA). Assessment of field and image endmembers revealed that the pan surface can be categorized into three major crust types based on diagnostic absorption features and mineralogical ground truth data. The mineralogical crust types are related to different zones of surface change as well as pan morphology that influences brine flow during the pan inundation and desiccation cycles. These combined information are used to spatially map depositional environments where the more dynamic halite crust concentrates in lower areas although stable gypsum and calcite/sepiolite crusts appear in higher elevated areas. KW - salt pan KW - playa KW - hyperspectral KW - multitemporal KW - change detection KW - evaporite minerals Y1 - 2016 U6 - https://doi.org/10.3390/rs9020170 SN - 2072-4292 VL - 9 IS - 2 PB - MDPI CY - Basel ER -