TY - JOUR A1 - Smetanová, Anna A1 - Müller, Anne A1 - Zargar, Morteza A1 - Suleiman, Mohamed A. A1 - Gholami, Faraz Rabei A1 - Mousavi, Maryam T1 - Mesoscale mapping of sediment source hotspots for dam sediment management in data-sparse semi-arid catchments JF - Water N2 - Land degradation and water availability in semi-arid regions are interdependent challenges for management that are influenced by climatic and anthropogenic changes. Erosion and high sediment loads in rivers cause reservoir siltation and decrease storage capacity, which pose risk on water security for citizens, agriculture, and industry. In regions where resources for management are limited, identifying spatial-temporal variability of sediment sources is crucial to decrease siltation. Despite widespread availability of rigorous methods, approaches simplifying spatial and temporal variability of erosion are often inappropriately applied to very data sparse semi-arid regions. In this work, we review existing approaches for mapping erosional hotspots, and provide an example of spatial-temporal mapping approach in two case study regions. The barriers limiting data availability and their effects on erosion mapping methods, their validation, and resulting prioritization of leverage management areas are discussed. KW - reservoir siltation KW - water security KW - water management KW - data sharing KW - spatial-temporal KW - erosion hotspots KW - mapping KW - global datasets KW - mesoscale KW - leverage areas Y1 - 2020 U6 - https://doi.org/10.3390/w12020396 SN - 2073-4441 VL - 12 IS - 2 SP - 1 EP - 24 PB - MDPI CY - Basel ER - TY - JOUR A1 - Vyse, Stuart Andrew A1 - Semiromi, Majid Taie A1 - Lischeid, Gunnar A1 - Merz, Christoph T1 - Characterizing hydrological processes within kettle holes using stable water isotopes in the Uckermark of northern Brandenburg, Germany JF - Hydrological Processes N2 - Understanding the hydrologic connectivity between kettle holes and shallow groundwater, particularly in reaction to the highly variable local meteorological conditions, is of paramount importance for tracing water in a hydro(geo)logically complex landscape and thus for integrated water resource management. This article is aimed at identifying the dominant hydrological processes affecting the kettle holes' water balance and their interactions with the shallow groundwater domain in the Uckermark region, located in the north-east of Germany. For this reason, based on the stable isotopes of oxygen (delta O-18) and hydrogen (delta H-2), an isotopic mass balance model was employed to compute the evaporative loss of water from the kettle holes from February to August 2017. Results demonstrated that shallow groundwater inflow may play the pivotal role in the processes taking part in the hydrology of the kettle holes in the Uckermark region. Based on the calculated evaporation/inflow (E/I) ratios, most of the kettle holes (86.7%) were ascertained to have a partially open, flow-through-dominated system. Moreover, we identified an inverse correlation between E/I ratios and the altitudes of the kettle holes. The same holds for electrical conductivity (EC) and the altitudes of the kettle holes. In accordance with the findings obtained from this study, a conceptual model explaining the interaction between the shallow groundwater and the kettle holes of Uckermark was developed. The model exhibited that across the highest altitudes, the recharge kettle holes are dominant, where a lower ratio of E/I and a lower EC was detected. By contrast, the lowest topographical depressions represent the discharge kettle holes, where a higher ratio of E/I and EC could be identified. The kettle holes existing in between were categorized as flow-through kettle holes through which the recharge takes place from one side and discharge from the other side. KW - evaporation KW - groundwater inflow KW - kettle hole KW - stable water isotope KW - surface–groundwater interactions Y1 - 2020 U6 - https://doi.org/10.1002/hyp.13699 SN - 0885-6087 SN - 1099-1085 VL - 34 IS - 8 SP - 1868 EP - 1887 PB - Wiley CY - New York ER - TY - JOUR A1 - Yamazaki, Yosuke A1 - Wendt, Vivien A1 - Miyoshi, Y. A1 - Stolle, Claudia A1 - Siddiqui, Tarique Adnan A1 - Kervalishvili, Guram N. A1 - Laštovička, J. A1 - Kozubek, M. A1 - Ward, W. A1 - Themens, D. R. A1 - Kristoffersen, S. A1 - Alken, Patrick T1 - September 2019 Antarctic sudden stratospheric warming BT - Quasi-6-Day wave burst and ionospheric effects JF - Geophysical Research Letters N2 - An exceptionally strong stationary planetary wave with Zonal Wavenumber 1 led to a sudden stratospheric warming (SSW) in the Southern Hemisphere in September 2019. Ionospheric data from European Space Agency's Swarm satellite constellation mission show prominent 6-day variations in the dayside low-latitude region at this time, which can be attributed to forcing from the middle atmosphere by the Rossby normal mode "quasi-6-day wave" (Q6DW). Geopotential height measurements by the Microwave Limb Sounder aboard National Aeronautics and Space Administration's Aura satellite reveal a burst of global Q6DW activity in the mesosphere and lower thermosphere during the SSW, which is one of the strongest in the record. The Q6DW is apparently generated in the polar stratosphere at 30-40 km, where the atmosphere is unstable due to strong vertical wind shear connected with planetary wave breaking. These results suggest that an Antarctic SSW can lead to ionospheric variability through wave forcing from the middle atmosphere. Plain Language Summary: A sudden stratospheric warming (SSW) is an extreme wintertime polar meteorological phenomenon occurring mostly over the Arctic region. Studies have shown that Arctic SSW can influence the entire atmosphere. In September 2019, a rare SSW event occurred in the Antarctic region, providing an opportunity to investigate its broader impact on the whole atmosphere. We present observations from the middle atmosphere and ionosphere during this event, noting unusually strong wave activity throughout this region. Our results suggest that an Antarctic SSW can have a significant impact on the whole atmosphere system similar to those due to Arctic events. KW - Rossby-normal modes KW - nonumiform background configuration KW - total electron-content KW - large-scale KW - planetary-waves KW - 5-day waves KW - equatorial electrojet KW - lower thermosphere KW - symmetric modes KW - 6.5-Day wave Y1 - 2020 U6 - https://doi.org/10.1029/2019GL086577 SN - 0094-8276 SN - 1944-8007 VL - 47 IS - 1 SP - 1 EP - 12 PB - Wiley CY - Hoboken ER - TY - JOUR A1 - Kuhlicke, Christian A1 - Masson, Torsten A1 - Kienzler, Sarah A1 - Sieg, Tobias A1 - Thieken, Annegret A1 - Kreibich, Heidi T1 - Multiple flood experiences and social resilience BT - Findings from three surveys on households and companies exposed to the 2013 flood in Germany JF - Weather, Climate, and Society N2 - Previous studies have explored the consequences of flood events for exposed households and companies by focusing on single flood events. Less is known about the consequences of experiencing repeated flood events for the resilience of households and companies. In this paper, we therefore explore how multiple floods experience affects the resilience of exposed households and companies. Resilience was made operational through individual appraisals of households and companies' ability to withstand and recover from material as well as health and psychological impacts of the 2013 flood in Germany. The paper is based on three different datasets including more than 2000 households and 300 companies that were affected by the 2013 flood. The surveys revealed that the resilience of households seems to increase, but only with regard to their subjectively appraised ability to withstand impacts on mobile goods and equipment (e.g., cars, TV, and radios). In regard to the ability of households to withstand overall financial consequences of repetitive floods, evidence for nonlinear (quadratic) trends can be found. With regard to psychological and health-related consequences, the findings are mixed but provide tentative evidence for eroding resilience among households. Companies' resilience increased with respect to material assets but appears to decrease with respect to ability to recover. We conclude by arguing that clear and operational definitions of resilience are required so that evidence-based resilience baselines can be established to assess whether resilience is eroding or improving over time. KW - social science KW - Europe Y1 - 2020 U6 - https://doi.org/10.1175/WCAS-D-18-0069.1 SN - 1948-8327 SN - 1948-8335 VL - 12 IS - 1 SP - 63 EP - 88 PB - American Meteorological Society CY - Boston ER - TY - JOUR A1 - Jing, Miao A1 - Kumar, Rohini A1 - Heße, Falk A1 - Thober, Stephan A1 - Rakovec, Oldrich A1 - Samaniego, Luis A1 - Attinger, Sabine T1 - Assessing the response of groundwater quantity and travel time distribution to 1.5, 2, and 3 °C global warming in a mesoscale central German basin JF - Hydrology and Earth System Sciences N2 - Groundwater is the biggest single source of high-quality freshwater worldwide, which is also continuously threatened by the changing climate. In this paper, we investigate the response of the regional groundwater system to climate change under three global warming levels (1.5, 2, and 3 ∘C) in a central German basin (Nägelstedt). This investigation is conducted by deploying an integrated modeling workflow that consists of a mesoscale hydrologic model (mHM) and a fully distributed groundwater model, OpenGeoSys (OGS). mHM is forced with climate simulations of five general circulation models under three representative concentration pathways. The diffuse recharges estimated by mHM are used as boundary forcings to the OGS groundwater model to compute changes in groundwater levels and travel time distributions. Simulation results indicate that groundwater recharges and levels are expected to increase slightly under future climate scenarios. Meanwhile, the mean travel time is expected to decrease compared to the historical average. However, the ensemble simulations do not all agree on the sign of relative change. Changes in mean travel time exhibit a larger variability than those in groundwater levels. The ensemble simulations do not show a systematic relationship between the projected change (in both groundwater levels and travel times) and the warming level, but they indicate an increased variability in projected changes with adjusting the enhanced warming level from 1.5 to 3 ∘C. Correspondingly, it is highly recommended to restrain the trend of global warming. KW - climate change impacts KW - hydrological models KW - coupled surface KW - water fluxes KW - catchment KW - recharge KW - dynamics KW - aquifer KW - flow KW - parameterization Y1 - 2020 U6 - https://doi.org/10.5194/hess-24-1511-2020 SN - 1607-7938 SN - 1027-5606 VL - 24 IS - 3 SP - 1511 EP - 1526 PB - Copernicus Publ. CY - Göttingen ER - TY - JOUR A1 - Bilbao-Lasa, Peru A1 - Jara Muñoz, Julius A1 - Pedoja, Kevin A1 - Álvarez, Irantzu A1 - Aranburu, Arantza A1 - Iriarte, Eneko A1 - Galparsoro, Ibon T1 - Submerged marine terraces identification and an approach for numerical modeling the sequence formation in the Bay of Biscay (Northeastern Iberian Peninsula) JF - Frontiers in Earth Science N2 - Submerged sequences of marine terraces potentially provide crucial information of past sea-level positions. However, the distribution and characteristics of drowned marine terrace sequences are poorly known at a global scale. Using bathymetric data and novel mapping and modeling techniques, we studied a submerged sequence of marine terraces in the Bay of Biscay with the objective to identify the distribution and morphologies of submerged marine terraces and the timing and conditions that allowed their formation and preservation. To accomplish the objectives a high-resolution bathymetry (5 m) was analyzed using Geographic Information Systems and TerraceM(R). The successive submerged terraces were identified using a Surface Classification Model, which linearly combines the slope and the roughness of the surface to extract fossil sea-cliffs and fossil rocky shore platforms. For that purpose, contour and hillshaded maps were also analyzed. Then, shoreline angles, a geomorphic marker located at the intersection between the fossil sea-cliff and platform, were mapped analyzing swath profiles perpendicular to the isobaths. Most of the submerged strandlines are irregularly preserved throughout the continental shelf. In summary, 12 submerged terraces with their shoreline angles between approximately: -13 m (T1), -30 and -32 m (T2), -34 and 41 m (T3), -44 and -47 m (T4), -49 and 53 m (T5), -55 and 58 m (T6), -59 and 62 m (T7), -65 and 67 m (T8), -68 and 70 m (T9), -74 and -77 m (T10), -83 and -86 m (T11) and -89 and 92 m (T12). Nevertheless, the ones showing the best lateral continuity and preservation in the central part of the shelf are T3, T4, T5, T7, T8, and T10. The age of the terraces has been estimated using a landscape evolution model. To simulate the formation and preservation of submerged terraces three different scenarios: (i) 20-0 ka; (ii) 128-0 ka; and (iii) 128-20 ka, were compared. The best scenario for terrace generation was between 128 and 20 Ka, where T3, T5, and T7 could have been formed. KW - marine terrace KW - submerged sequence KW - digital bathymetric model KW - TerraceM KW - numerical modeling KW - Bay of Biscay Y1 - 2020 U6 - https://doi.org/10.3389/feart.2020.00047 SN - 2296-6463 VL - 8 IS - 47 SP - 1 EP - 20 PB - Frontiers Media CY - Lausanne ER - TY - JOUR A1 - Cao, Xianyong A1 - Tian, Fang A1 - Andreev, Andrei A1 - Anderson, Patricia M. A1 - Lozhkin, Anatoly V. A1 - Bezrukova, Elena A1 - Ni, Jian A1 - Rudaya, Natalia A1 - Stobbe, Astrid A1 - Wieczorek, Mareike A1 - Herzschuh, Ulrike T1 - A taxonomically harmonized and temporally standardized fossil pollen dataset from Siberia covering the last 40 kyr JF - Earth System Science Data N2 - Pollen records from Siberia are mostly absent in global or Northern Hemisphere synthesis works. Here we present a taxonomically harmonized and temporally standardized pollen dataset that was synthesized using 173 palynological records from Siberia and adjacent areas (northeastern Asia, 42-75 degrees N, 50-180 degrees E). Pollen data were taxonomically harmonized, i.e. the original 437 taxa were assigned to 106 combined pollen taxa. Age-depth models for all records were revised by applying a constant Bayesian age-depth modelling routine. The pollen dataset is available as count data and percentage data in a table format (taxa vs. samples), with age information for each sample. The dataset has relatively few sites covering the last glacial period between 40 and 11.5 ka (calibrated thousands of years before 1950 CE) particularly from the central and western part of the study area. In the Holocene period, the dataset has many sites from most of the area, with the exception of the central part of Siberia. Of the 173 pollen records, 81 % of pollen counts were downloaded from open databases (GPD, EPD, PANGAEA) and 10 % were contributions by the original data gatherers, while a few were digitized from publications. Most of the pollen records originate from peatlands (48 %) and lake sediments (33 %). Most of the records (83 %) have >= 3 dates, allowing the establishment of reliable chronologies. The dataset can be used for various purposes, including pollen data mapping (example maps for Larix at selected time slices are shown) as well as quantitative climate and vegetation reconstructions. The datasets for pollen counts and pollen percentages are available at https://doi.org/10.1594/PANGAEA.898616 (Cao et al., 2019a), also including the site information, data source, original publication, dating data, and the plant functional type for each pollen taxa. KW - Late Quaternary vegetation KW - Holocene environmental history KW - eastern continental Asia KW - plant macrofossil data KW - late pleistocene KW - paleoenvironmental records KW - Verkhoyansk mountains KW - climate dynamics KW - glacial maximum KW - Northern Asia Y1 - 2020 U6 - https://doi.org/10.5194/essd-12-119-2020 SN - 1866-3508 SN - 1866-3516 VL - 12 IS - 1 SP - 119 EP - 135 PB - Copernics Publications CY - Katlenburg-Lindau ER - TY - JOUR A1 - Huber, Veronika A1 - Krummenauer, Linda A1 - Peña-Ortiz, Cristina A1 - Lange, Stefan A1 - Gasparrini, Antonio A1 - Vicedo-Cabrera, Ana Maria A1 - Garcia-Herrera, Ricardo A1 - Frieler, Katja T1 - Temperature-related excess mortality in German cities at 2 °C and higher degrees of global warming JF - Environmental Research N2 - Background: Investigating future changes in temperature-related mortality as a function of global mean temperature (GMT) rise allows for the evaluation of policy-relevant climate change targets. So far, only few studies have taken this approach, and, in particular, no such assessments exist for Germany, the most populated country of Europe. Methods: We assess temperature-related mortality in 12 major German cities based on daily time-series of all-cause mortality and daily mean temperatures in the period 1993-2015, using distributed-lag non-linear models in a two-stage design. Resulting risk functions are applied to estimate excess mortality in terms of GMT rise relative to pre-industrial levels, assuming no change in demographics or population vulnerability. Results: In the observational period, cold contributes stronger to temperature-related mortality than heat, with overall attributable fractions of 5.49% (95%CI: 3.82-7.19) and 0.81% (95%CI: 0.72-0.89), respectively. Future projections indicate that this pattern could be reversed under progressing global warming, with heat-related mortality starting to exceed cold-related mortality at 3 degrees C or higher GMT rise. Across cities, projected net increases in total temperature-related mortality were 0.45% (95%CI: -0.02-1.06) at 3 degrees C, 1.53% (95%CI: 0.96-2.06) at 4 degrees C, and 2.88% (95%CI: 1.60-4.10) at 5 degrees C, compared to today's warming level of 1 degrees C. By contrast, no significant difference was found between projected total temperature-related mortality at 2 degrees C versus 1 degrees C of GMT rise. Conclusions: Our results can inform current adaptation policies aimed at buffering the health risks from increased heat exposure under climate change. They also allow for the evaluation of global mitigation efforts in terms of local health benefits in some of Germany's most populated cities. KW - temperature-related mortality KW - climate change KW - Future projections KW - Germany KW - global mean temperature Y1 - 2020 U6 - https://doi.org/10.1016/j.envres.2020.109447 SN - 0013-9351 SN - 1096-0953 VL - 186 SP - 1 EP - 10 PB - Elsevier CY - San Diego, California ER - TY - JOUR A1 - Dietze, Elisabeth A1 - Mangelsdorf, Kai A1 - Andreev, Andrei A1 - Karger, Cornelia A1 - Schreuder, Laura T. A1 - Hopmans, Ellen C. A1 - Rach, Oliver A1 - Sachse, Dirk A1 - Wennrich, Volker A1 - Herzschuh, Ulrike T1 - Relationships between low-temperature fires, climate and vegetation during three late glacials and interglacials of the last 430 kyr in northeastern Siberia reconstructed from monosaccharide anhydrides in Lake El’gygytgyn sediments JF - Climate of the Past N2 - Landscapes in high northern latitudes are assumed to be highly sensitive to future global change, but the rates and long-term trajectories of changes are rather uncertain. In the boreal zone, fires are an important factor in climate-vegetation interactions and biogeochemical cycles. Fire regimes are characterized by small, frequent, low-intensity fires within summergreen boreal forests dominated by larch, whereas evergreen boreal forests dominated by spruce and pine burn large areas less frequently but at higher intensities. Here, we explore the potential of the monosaccharide anhydrides (MA) levoglucosan, mannosan and galactosan to serve as proxies of low-intensity biomass burning in glacial-to-interglacial lake sediments from the high northern latitudes. We use sediments from Lake El'gygytgyn (cores PG 1351 and ICDP 5011-1), located in the far north-east of Russia, and study glacial and interglacial samples of the last 430 kyr (marine isotope stages 5e, 6, 7e, 8, 11c and 12) that had different climate and biome configurations. Combined with pollen and non-pollen palynomorph records from the same samples, we assess how far the modern relationships between fire, climate and vegetation persisted during the past, on orbital to centennial timescales. We find that MAs attached to particulates were well-preserved in up to 430 kyr old sediments with higher influxes from low-intensity biomass burning in interglacials compared to glacials. MA influxes significantly increase when summergreen boreal forest spreads closer to the lake, whereas they decrease when tundra-steppe environments and, especially, Sphagnum peatlands spread. This suggests that low-temperature fires are a typical characteristic of Siberian larch forests also on long timescales. The results also suggest that low-intensity fires would be reduced by vegetation shifts towards very dry environments due to reduced biomass availability, as well as by shifts towards peatlands, which limits fuel dryness. In addition, we observed very low MA ratios, which we interpret as high contributions of galactosan and mannosan from biomass sources other than those currently monitored, such as the moss-lichen mats in the understorey of the summergreen boreal forest. Overall, sedimentary MAs can provide a powerful proxy for fire regime reconstructions and extend our knowledge of long-term natural fire-climate-vegetation feedbacks in the high northern latitudes. KW - molecular tracers KW - organic aerosols KW - emission factors KW - carbonaceous aerosols KW - pollen records KW - core PG1351 KW - biomass KW - holocene KW - levoglucosan KW - charcoal Y1 - 2020 U6 - https://doi.org/10.5194/cp-16-799-2020 SN - 1814-9332 SN - 1814-9324 VL - 16 IS - 2 SP - 788 EP - 818 PB - Copernicus Publications CY - Göttingen ER - TY - JOUR A1 - Kuhlicke, Christian A1 - Seebauer, Sebastian A1 - Hudson, Paul A1 - Begg, Chloe A1 - Bubeck, Philip A1 - Dittmer, Cordula A1 - Grothmann, Torsten A1 - Heidenreich, Anna A1 - Kreibich, Heidi A1 - Lorenz, Daniel F. A1 - Masson, Torsten A1 - Reiter, Jessica A1 - Thaler, Thomas A1 - Thieken, Annegret A1 - Bamberg, Sebastian T1 - The behavioral turn in flood risk management, its assumptions and potential implications JF - WIREs Water N2 - Recent policy changes highlight the need for citizens to take adaptive actions to reduce flood-related impacts. Here, we argue that these changes represent a wider behavioral turn in flood risk management (FRM). The behavioral turn is based on three fundamental assumptions: first, that the motivations of citizens to take adaptive actions can be well understood so that these motivations can be targeted in the practice of FRM; second, that private adaptive measures and actions are effective in reducing flood risk; and third, that individuals have the capacities to implement such measures. We assess the extent to which the assumptions can be supported by empirical evidence. We do this by engaging with three intellectual catchments. We turn to research by psychologists and other behavioral scientists which focus on the sociopsychological factors which influence individual motivations (Assumption 1). We engage with economists, engineers, and quantitative risk analysts who explore the extent to which individuals can reduce flood related impacts by quantifying the effectiveness and efficiency of household-level adaptive measures (Assumption 2). We converse with human geographers and sociologists who explore the types of capacities households require to adapt to and cope with threatening events (Assumption 3). We believe that an investigation of the behavioral turn is important because if the outlined assumptions do not hold, there is a risk of creating and strengthening inequalities in FRM. Therefore, we outline the current intellectual and empirical knowledge as well as future research needs. Generally, we argue that more collaboration across intellectual catchments is needed, that future research should be more theoretically grounded and become methodologically more rigorous and at the same time focus more explicitly on the normative underpinnings of the behavioral turn. KW - capacities KW - effectiveness KW - motivation KW - resources KW - risk governance KW - vulnerability Y1 - 2020 U6 - https://doi.org/10.1002/wat2.1418 SN - 2049-1948 VL - 7 IS - 3 SP - 1 EP - 22 PB - Wiley-Blackwell CY - Hoboken ER - TY - JOUR A1 - Stoof-Leichsenring, Kathleen Rosemarie A1 - Pestryakova, Luidmila Agafyevna A1 - Epp, Laura Saskia A1 - Herzschuh, Ulrike T1 - Phylogenetic diversity and environment form assembly rules for Arctic diatom genera BT - a study on recent and ancient sedimentary DNA JF - Journal of Biogeography N2 - Aim This study investigates taxonomic and phylogenetic diversity in diatom genera to evaluate assembly rules for eukaryotic microbes across the Siberian tree line. We first analysed how phylogenetic distance relates to taxonomic richness and turnover. Second, we used relatedness indices to evaluate if environmental filtering or competition influences the assemblies in space and through time. Third, we used distance-based ordination to test which environmental variables shape diatom turnover. Location Yakutia and Taymyria, Russia: we sampled 78 surface sediments and a sediment core, extending to 7,000 years before present, to capture the forest-tundra transition in space and time respectively. Taxon Arctic freshwater diatoms. Methods We applied metabarcoding to retrieve diatom diversity from surface and core sedimentary DNA. The taxonomic assignment binned sequence types (lineages) into genera and created taxonomic (abundance of lineages within different genera) and phylogenetic datasets (phylogenetic distances of lineages within different genera). Results Contrary to our expectations, we find a unimodal relationship between phylogenetic distance and richness in diatom genera. We discern a positive relationship between phylogenetic distance and taxonomic turnover in spatially and temporally distributed diatom genera. Furthermore, we reveal positive relatedness indices in diatom genera across the spatial environmental gradient and predominantly in time slices at a single location, with very few exceptions assuming effects of competition. Distance-based ordination of taxonomic and phylogenetic turnover indicates that lake environment variables, like HCO3- and water depth, largely explain diatom turnover. Main conclusion Phylogenetic and abiotic assembly rules are important in understanding the regional assembly of diatom genera across lakes in the Siberian tree line ecotone. Using a space-time approach we are able to exclude the influence of geography and elucidate that lake environmental variables primarily shape the assemblies. We conclude that some diatom genera have greater capabilities to adapt to environmental changes, whereas others will be putatively replaced or lost due to the displacement of the Arctic tundra biome under recent global warming. KW - ancient sedimentary DNA KW - Arctic lakes KW - assembly rules KW - climate change KW - diatoms KW - environmental filtering KW - phylogenetic diversity KW - Siberian tree line Y1 - 2020 U6 - https://doi.org/10.1111/jbi.13786 SN - 0305-0270 SN - 1365-2699 VL - 47 IS - 5 SP - 1166 EP - 1179 PB - Wiley-Blackwell CY - Oxford ER - TY - JOUR A1 - Kärcher, Oskar A1 - Filstrup, Christopher T. A1 - Brauns, Mario A1 - Tasevska, Orhideja A1 - Patceva, Suzana A1 - Hellwig, Niels A1 - Walz, Ariane A1 - Frank, Karin A1 - Markovic, Danijela T1 - Chlorophyll a relationships with nutrients and temperature, and predictions for lakes across perialpine and Balkan mountain regions JF - Inland Waters N2 - Model-derived relationships between chlorophyll a (Chl-a) and nutrients and temperature have fundamental implications for understanding complex interactions among water quality measures used for lake classification, yet accuracy comparisons of different approaches are scarce. Here, we (1) compared Chl-a model performances across linear and nonlinear statistical approaches; (2) evaluated single and combined effects of nutrients, depth, and temperature as lake surface water temperature (LSWT) or altitude on Chl-a; and (3) investigated the reliability of the best water quality model across 13 lakes from perialpine and central Balkan mountain regions. Chl-a was modelled using in situ water quality data from 157 European lakes; elevation data and LSWT in situ data were complemented by remote sensing measurements. Nonlinear approaches performed better, implying complex relationships between Chl-a and the explanatory variables. Boosted regression trees, as the best performing approach, accommodated interactions among predictor variables. Chl-a-nutrient relationships were characterized by sigmoidal curves, with total phosphorus having the largest explanatory power for our study region. In comparison with LSWT, utilization of altitude, the often-used temperature surrogate, led to different influence directions but similar predictive performances. These results support utilizing altitude in models for Chl-a predictions. Compared to Chl-a observations, Chl-a predictions of the best performing approach for mountain lakes (oligotrophic-eutrophic) led to minor differences in trophic state categorizations. Our findings suggest that both models with LSWT and altitude are appropriate for water quality predictions of lakes in mountain regions and emphasize the importance of incorporating interactions among variables when facing lake management challenges. KW - chlorophyll a KW - nutrients KW - Ohrid-Prespa region KW - perialpine lakes KW - water temperature Y1 - 2020 U6 - https://doi.org/10.1080/20442041.2019.1689768 SN - 2044-2041 SN - 2044-205X VL - 10 IS - 1 SP - 29 EP - 41 PB - Taylor & Francis CY - London ER - TY - JOUR A1 - Scherler, Dirk A1 - Schwanghart, Wolfgang T1 - Drainage divide networks - part 1: Identification and ordering in digital elevation models JF - Earth surface dynamics : ESURF N2 - We propose a novel way to measure and analyze networks of drainage divides from digital elevation models. We developed an algorithm that extracts drainage divides based on the drainage basin boundaries defined by a stream network. In contrast to streams, there is no straightforward approach to order and classify divides, although it is intuitive that some divides are more important than others. A meaningful way of ordering divides is the average distance one would have to travel down on either side of a divide to reach a common stream location. However, because measuring these distances is computationally expensive and prone to edge effects, we instead sort divide segments based on their tree-like network structure, starting from endpoints at river confluences. The sorted nature of the network allows for assigning distances to points along the divides, which can be shown to scale with the average distance downslope to the common stream location. Furthermore, because divide segments tend to have characteristic lengths, an ordering scheme in which divide orders increase by 1 at junctions mimics these distances. We applied our new algorithm to the Big Tujunga catchment in the San Gabriel Mountains of southern California and studied the morphology of the drainage divide network. Our results show that topographic metrics, like the downstream flow distance to a stream and hillslope relief, attain characteristic values that depend on the drainage area threshold used to derive the stream network. Portions along the divide network that have lower than average relief or are closer than average to streams are often distinctly asymmetric in shape, suggesting that these divides are unstable. Our new and automated approach thus helps to objectively extract and analyze divide networks from digital elevation models. Y1 - 2020 U6 - https://doi.org/10.5194/esurf-8-245-2020 SN - 2196-6311 SN - 2196-632X VL - 8 IS - 2 SP - 245 EP - 259 PB - Copernicus Publ. CY - Göttingen ER - TY - JOUR A1 - Grotheer, Hendrik A1 - Meyer, Vera A1 - Riedel, Theran A1 - Pfalz, Gregor A1 - Mathieu, Lucie A1 - Hefter, Jens H. A1 - Gentz, Torben A1 - Lantuit, Hugues A1 - Mollennauer, Gesine A1 - Fritz, Michael T1 - Burial and origin of permafrost-derived carbon in the nearshore zone of the southern Canadian Beaufort Sea JF - Geophysical research letters N2 - Detailed organic geochemical and carbon isotopic (delta C-13 and Delta C-14) analyses are performed on permafrost deposits affected by coastal erosion (Herschel Island, Canadian Beaufort Sea) and adjacent marine sediments (Herschel Basin) to understand the fate of organic carbon in Arctic nearshore environments. We use an end-member model based on the carbon isotopic composition of bulk organic matter to identify sources of organic carbon. Monte Carlo simulations are applied to quantify the contribution of coastal permafrost erosion to the sedimentary carbon budget. The models suggest that similar to 40% of all carbon released by local coastal permafrost erosion is efficiently trapped and sequestered in the nearshore zone. This highlights the importance of sedimentary traps in environments such as basins, lagoons, troughs, and canyons for the carbon sequestration in previously poorly investigated, nearshore areas. Plain Language Summary Increasing air and sea surface temperatures at high latitudes leads to accelerated thaw, destabilization, and erosion of perennially frozen soils (i.e., permafrost), which are often rich in organic carbon. Coastal erosion leads to an increased mobilization of organic carbon into the Arctic Ocean, which there can be converted into greenhouse gases and may therefore contribute to further warming. Carbon decomposition can be limited if organic matter is efficiently deposited on the seafloor, buried in marine sediments, and thus removed from the short-term carbon cycle. Basins, canyons, and troughs near the coastline can serve as sediment traps and potentially accommodate large quantities of organic carbon along the Arctic coast. Here we use biomarkers (source-specific molecules), stable carbon isotopes, and radiocarbon to identify the sources of organic carbon in the nearshore zone of the southern Canadian Beaufort Sea near Herschel Island. We quantify the contribution of coastal permafrost erosion to the sedimentary carbon budget of the area and estimate that more than a third of all carbon released by local permafrost erosion is efficiently trapped in marine sediments. This highlights the importance of regional sediment traps for carbon sequestration. Y1 - 2020 U6 - https://doi.org/10.1029/2019GL085897 SN - 0094-8276 SN - 1944-8007 VL - 47 IS - 3 PB - Wiley CY - Hoboken, NJ ER - TY - JOUR A1 - Castino, Fabiana A1 - Bookhagen, Bodo A1 - De la Torre, Alejandro T1 - Atmospheric dynamics of extreme discharge events from 1979 to 2016 in the southern Central Andes JF - Climate dynamics : observational, theoretical and computational research on the climate system N2 - During the South-American Monsoon season, deep convective systems occur at the eastern flank of the Central Andes leading to heavy rainfall and flooding. We investigate the large- and meso-scale atmospheric dynamics associated with extreme discharge events (> 99.9th percentile) observed in two major river catchments meridionally stretching from humid to semi-arid conditions in the southern Central Andes. Based on daily gauge time series and ERA-Interim reanalysis, we made the following three key observations: (1) for the period 1940-2016 daily discharge exhibits more pronounced variability in the southern, semi-arid than in the northern, humid catchments. This is due to a smaller ratio of discharge magnitudes between intermediate (0.2 year return period) and rare events (20 year return period) in the semi-arid compared to the humid areas; (2) The climatological composites of the 40 largest discharge events showed characteristic atmospheric features of cold surges based on 5-day time-lagged sequences of geopotential height at different levels in the troposphere; (3) A subjective classification revealed that 80% of the 40 largest discharge events are mainly associated with the north-northeastward migration of frontal systems and 2/3 of these are cold fronts, i.e. cold surges. This work highlights the importance of cold surges and their related atmospheric processes for the generation of heavy rainfall events and floods in the southern Central Andes. KW - South American monsoon system KW - cold surges KW - orographic barrier KW - mesoscale convective systems KW - extreme discharge KW - daily-discharge time KW - series ERA-interim Y1 - 2019 U6 - https://doi.org/10.1007/s00382-020-05458-1 SN - 0930-7575 SN - 1432-0894 VL - 55 IS - 11-12 SP - 3485 EP - 3505 PB - Springer CY - Berlin ; Heidelberg [u.a.] ER - TY - JOUR A1 - Barthel, Martin A1 - Bürkner, Hans-Joachim T1 - Ukraine and the big moral divide BT - what biased media coverage means to East European borders JF - Geopolitics N2 - Geopolitical shifts and the changing significance of borders in the EU's neighbourhood are usually understood as a matter of international power politics. Factors that accompany geopolitical impact on borders, such as media coverage of geopolitical change, often appear as secondary or irrelevant. However the recent Ukraine conflict revealed the contrary as pro-EU attitudes were strongly supported by 'western' media. Therefore this paper seeks to clarify the role of news media in creating perspectives and attitudes on geopolitical shifts and the significance of European borders. Empirical evidence on the coverage of the evolving Ukraine crisis by German news sources portrays the media as promoters of biased framings and imaginaries which suggest that the EU be a potential conflict party in the newly evolving geostrategic confrontation in its eastern neighbourhood. The findings indicate that during critical periods of the Ukraine crisis media reports combined rising euphoria about Europe and 'the West', as defenders of the 'good cause', with excessive moral polarising and the discursive normalisation of a rhetoric of escalation. Imaginaries of a bipolar world (The West against Russia) and a new Cold War prepared the ground for a new understanding of European borders and neighbourhood relations as being manipulable at will. Y1 - 2019 U6 - https://doi.org/10.1080/14650045.2018.1561437 SN - 1465-0045 SN - 1557-3028 VL - 25 IS - 3 SP - 633 EP - 657 PB - Routledge, Taylor & Francis Group CY - Philadelphia, Pa. [u.a] ER - TY - JOUR A1 - Ramachandran, Srikanthan A1 - Rupakheti, Maheswar A1 - Lawrence, Mark T1 - Aerosol-induced atmospheric heating rate decreases over South and East Asia as a result of changing content and composition JF - Scientific reports N2 - Aerosol emissions from human activities are extensive and changing rapidly over Asia. Model simulations and satellite observations indicate a dipole pattern in aerosol emissions and loading between South Asia and East Asia, two of the most heavily polluted regions of the world. We examine the previously unexplored diverging trends in the existing dipole pattern of aerosols between East and South Asia using the high quality, two-decade long ground-based time series of observations of aerosol properties from the Aerosol Robotic Network (AERONET), from satellites (Moderate Resolution Imaging Spectroradiometer (MODIS) and Ozone Monitoring Instrument (OMI)), and from model simulations (Modern-Era Retrospective Analysis for Research and Applications, version 2 (MERRA-2). The data cover the period since 2001 for Kanpur (South Asia) and Beijing (East Asia), two locations taken as being broadly representative of the respective regions. Since 2010 a dipole in aerosol optical depth (AOD) is maintained, but the trend is reversed-the decrease in AOD over Beijing (East Asia) is rapid since 2010, being 17% less in current decade compared to first decade of twenty-first century, while the AOD over South Asia increased by 12% during the same period. Furthermore, we find that the aerosol composition is also changing over time. The single scattering albedo (SSA), a measure of aerosol's absorption capacity and related to aerosol composition, is slightly higher over Beijing than Kanpur, and has increased from 0.91 in 2002 to 0.93 in 2017 over Beijing and from 0.89 to 0.92 during the same period over Kanpur, confirming that aerosols in this region have on an average become more scattering in nature. These changes have led to a notable decrease in aerosol-induced atmospheric heating rate (HR) over both regions between the two decades, decreasing considerably more over East Asia (- 31%) than over South Asia (- 9%). The annual mean HR is lower now, it is still large (>= 0.6 K per day), which has significant climate implications. The seasonal trends in AOD, SSA and HR are more pronounced than their respective annual trends over both regions. The seasonal trends are caused mainly by the increase/decrease in anthropogenic aerosol emissions (sulfate, black carbon and organic carbon) while the natural aerosols (dust and sea salt) did not change significantly over South and East Asia during the last two decades. The MERRA-2 model is able to simulate the observed trends in AODs well but not the magnitude, while it also did not simulate the SSA values or trends well. These robust findings based on observations of key aerosol parameters and previously unrecognized diverging trends over South and East Asia need to be accounted for in current state-of-the-art climate models to ensure accurate quantification of the complex and evolving impact of aerosols on the regional climate over Asia. Y1 - 2020 U6 - https://doi.org/10.1038/s41598-020-76936-z SN - 2045-2322 VL - 10 IS - 1 PB - Macmillan Publishers Limited, part of Springer Nature CY - [London] ER - TY - JOUR A1 - Mtilatila, Lucy Mphatso Ng'ombe A1 - Bronstert, Axel A1 - Shrestha, Pallav A1 - Kadewere, Peter A1 - Vormoor, Klaus Josef T1 - Susceptibility of water resources and hydropower production to climate change in the tropics BT - the case of Lake Malawi and Shire River Basins, SE Africa JF - Hydrology : open access journal N2 - The sensitivity of key hydrologic variables and hydropower generation to climate change in the Lake Malawi and Shire River basins is assessed. The study adapts the mesoscale Hydrological Model (mHM) which is applied separately in the Upper Lake Malawi and Shire River basins. A particular Lake Malawi model, which focuses on reservoir routing and lake water balance, has been developed and is interlinked between the two basins. Climate change projections from 20 Coordinated Regional Climate Downscaling Experiment (CORDEX) models for Africa based on two scenarios (RCP4.5 and RCP8.5) for the periods 2021-2050 and 2071-2100 are used. An annual temperature increase of 1 degrees C decreases mean lake level and outflow by 0.3 m and 17%, respectively, signifying the importance of intensified evaporation for Lake Malawi's water budget. Meanwhile, a +5% (-5%) deviation in annual rainfall changes mean lake level by +0.7 m (-0.6 m). The combined effects of temperature increase and rainfall decrease result in significantly lower flows in the Shire River. The hydrological river regime may change from perennial to seasonal with the combination of annual temperature increase and precipitation decrease beyond 1.5 degrees C (3.5 degrees C) and -20% (-15%). The study further projects a reduction in annual hydropower production between 1% (RCP8.5) and 2.5% (RCP4.5) during 2021-2050 and between 5% (RCP4.5) and 24% (RCP8.5) during 2071-2100. The results show that it is of great importance that a further development of hydro energy on the Shire River should take into account the effects of climate change, e.g., longer low flow periods and/or higher discharge fluctuations, and thus uncertainty in the amount of electricity produced. KW - Lake Malawi Basin KW - Shire River Basin KW - lake water balance KW - climate change impacts in the tropics KW - hydropower generation KW - response surface analysis KW - sensitivity analysis Y1 - 2020 U6 - https://doi.org/10.3390/hydrology7030054 SN - 2306-5338 VL - 7 IS - 3 PB - MDPI CY - Basel ER - TY - JOUR A1 - Kellermann, Patric A1 - Schröter, Kai A1 - Thieken, Annegret A1 - Haubrock, Sören-Nils A1 - Kreibich, Heidi T1 - The object-specific flood damage database HOWAS 21 JF - Natural hazards and earth system sciences N2 - The Flood Damage Database HOWAS 21 contains object-specific flood damage data resulting from fluvial, pluvial and groundwater flooding. The datasets incorporate various variables of flood hazard, exposure, vulnerability and direct tangible damage at properties from several economic sectors. The main purpose of development of HOWAS 21 was to support forensic flood analysis and the derivation of flood damage models. HOWAS 21 was first developed for Germany and currently almost exclusively contains datasets from Germany. However, its scope has recently been enlarged with the aim to serve as an international flood damage database; e.g. its web application is now available in German and English. This paper presents the recent advancements of HOWAS 21 and highlights exemplary analyses to demonstrate the use of HOWAS 21 flood damage data. The data applications indicate a large potential of the database for fostering a better understanding and estimation of the consequences of flooding. Y1 - 2020 U6 - https://doi.org/10.5194/nhess-20-2503-2020 SN - 1561-8633 SN - 1684-9981 VL - 20 IS - 9 SP - 2503 EP - 2519 PB - Copernicus CY - Göttingen ER - TY - JOUR A1 - Zhang, Yan-qiu A1 - Guo, Zeng-hui A1 - Chen, Dai-zhao T1 - Porosity distribution in cyclic dolomites of the Lower Qiulitag Group (Upper Cambrian) in northwestern Tarim Basin, China JF - China geology N2 - Increasing interests in hydrocarbon resources at depths have drawn greater attentions to the deeply-buried carbonate reservoirs in the Tarim Basin in China. In this study, the cyclic dolomite rocks of Upper Cambrian Lower Qiulitag Group from four outcrop sections in northwestern Tarim Basin were selected to investigate and evaluate the petrophysical properties in relation to depositional facies and cyclicity. The Lower Qiulitag Group includes ten lithofacies, which were deposited in intermediate to shallow subtidal, restricted shallow subtidal, intertidal, and supratidal environments on a carbonate ramp system. These lithofacies are vertically stacked into repeated shallowing-upward, meter-scale cycles which are further grouped into six third-order depositional sequences (Sq1 to Sq6). There are variable types of pore spaces in the Lower Qiulitag Group dolomite rocks, including interparticle, intraparticle, and fenestral pores of primary origin, inter crystal, and vuggy pores of late diagenetic modification. The porosity in the dolomites is generally facies-selective as that the microbially-originated thrombolites and stromatolites generally yield a relatively high porosity. In contrast, the high-energy ooidal grainstones generally have very low porosity. In this case, the microbialite-based peritidal cycles and peritidal cycle-dominated highstand (or regressive) successions have relatively high volumes of pore spaces, although highly fluctuating (or vertical inhomogeneous). Accordingly, the grainstone-based subtidal cycles and subtidal cycle-dominated transgressive successions generally yield extremely low porosity. This scenario indicates that porosity development and preservation in the thick dolomite successions are primarily controlled by depositional facies which were influenced by sea-level fluctuations of different orders and later diagenetic overprinting. KW - Dolomites KW - porosity KW - cyclicity KW - Upper Cambrian KW - stromatolite KW - microbial KW - build up KW - oil-gas basin KW - oil-gas exploration engineering KW - Tarim Basin KW - China Y1 - 2020 UR - http://en.cgsjournals.com/zgdzdcqkw-data/zgdzyw/2020/3/PDF/cg2020026.pdf SN - 2096-5192 SN - 2589-9430 VL - 3 IS - 3 SP - 425 EP - 444 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Wang, Lei A1 - Kwiatek, Grzegorz A1 - Rybacki, Erik A1 - Bonnelye, Audrey A1 - Bohnhoff, Marco A1 - Dresen, Georg T1 - Laboratory study on fluid-induced fault slip behavior: the role of fluid pressurization rate JF - Geophysical research letters : GRL N2 - Understanding the physical mechanisms governing fluid-induced fault slip is important for improved mitigation of seismic risks associated with large-scale fluid injection. We conducted fluid-induced fault slip experiments in the laboratory on critically stressed saw-cut sandstone samples with high permeability using different fluid pressurization rates. Our experimental results demonstrate that fault slip behavior is governed by fluid pressurization rate rather than injection pressure. Slow stick-slip episodes (peak slip velocity < 4 mu m/s) are induced by fast fluid injection rate, whereas fault creep with slip velocity < 0.4 mu m/s mainly occurs in response to slow fluid injection rate. Fluid-induced fault slip may remain mechanically stable for loading stiffness larger than fault stiffness. Independent of fault slip mode, we observed dynamic frictional weakening of the artificial fault at elevated pore pressure. Our observations highlight that varying fluid injection rates may assist in reducing potential seismic hazards of field-scale fluid injection projects.
Plain Language Summary Human-induced earthquakes from field-scale fluid injection projects including enhanced geothermal system and deep wastewater injection have been documented worldwide. Although it is clear that fluid pressure plays a crucial role in triggering fault slip, the physical mechanism behind induced seismicity still remains poorly understood. We performed laboratory tests, and here we present two fluid-induced slip experiments conducted on permeable Bentheim sandstone samples crosscut by a fault that is critically stressed. Fault slip is then triggered by pumping the water from the bottom end of the sample at different fluid injection rates. Our results show that fault slip is controlled by fluid pressure increase rate rather than by the absolute magnitude of fluid pressure. In contrast to episodes of relatively rapid but stable sliding events caused by a fast fluid injection rate, fault creep is observed during slow fluid injection. Strong weakening of the dynamic friction coefficient of the experimental fault is observed at elevated pore pressure, independent of fault slip mode. These results may provide a better understanding of the complex behavior of fluid-induced fault slip on the field scale. KW - fault slip KW - fluid injection KW - induced seismicity KW - fluid pressurization KW - rate KW - stick-slip KW - fault creep Y1 - 2020 U6 - https://doi.org/10.1029/2019GL086627 SN - 0094-8276 SN - 1944-8007 VL - 47 IS - 6 PB - Wiley CY - Hoboken, NJ ER - TY - JOUR A1 - Wang, Hao A1 - Wang, Xuejiang A1 - Wang, Weishi A1 - Su, Yinglong A1 - Zhao, Jianfu T1 - Reuse of a phosphorus recovery product (struvite/palygorskite) from nutrient wastewater for copper remediation in aqueous solution and soil JF - Geoderma : an international journal of soil science N2 - In this study, a phosphorus recovery product, struvite palygorskite (S-PAL), obtained from nutrient-rich wastewater by using MgO modified palygorskite was applied for copper remediation in aqueous solution and contaminated soil to achieve waste recycling. The effects of contact time, initial pH, initial Cu(II) concentration and reaction temperature on Cu(II) adsorption in aqueous solution were intensively testified. Pseudo-second-order model was able to properly describe Cu(II) adsorption kinetics by using palygorskite (PAL) and S-PAL, and S-PAL exhibited higher adsorption amount (106.27 mg/g) than PAL (8.46 mg/g) at pH of 4. Cu(II) adsorption on PAL and S-PAL could be well fitted by Freundlich isotherm and Langmuir isotherm, respectively. The calculated thermodynamic parameters indicated that Cu(II) adsorption onto PAL and S-PAL were spontaneous and endothermic. A 28-day soil incubation experiment was conducted to evaluate the effects of PAL and S-PAL with three different rates (1%, 5% and 10% w/w) on Cu immobilization in contaminated soil. In the immobilization test, Cu extracted by 0.01 mol/L CaCl2 after seven days incubation significantly decreased with increasing rate of PAL and S-PAL. BCR sequential extraction results showed the significant decrease of acid soluble Cu and a concomitant increase of the residual fraction of Cu after S-PAL and PAL addition. XRD patterns of soil samples after treatment by PAL and S-PAL showed the formation of Cu0.6Mg1.3Si2O6 and Cu-3.04(PO4)(2)OH0.08 center dot 2H(2)O, which indicated that silanol groups and phosphate exhibited affinity for Cu in the soil. KW - palygorskite KW - struvite KW - adsorption KW - copper immobilization KW - waste reuse Y1 - 2020 U6 - https://doi.org/10.1016/j.geoderma.2019.113955 SN - 0016-7061 SN - 1872-6259 VL - 357 PB - Elsevier Science CY - Amsterdam [u.a.] ER - TY - JOUR A1 - Weimar, Jannis A1 - Köhli, Markus A1 - Budach, Christian A1 - Schmidt, Ulrich T1 - Large-scale boron-lined neutron detection systems as a 3He alternative for Cosmic Ray Neutron Sensing JF - Frontiers in water N2 - Cosmic-Ray neutron sensors are widely used to determine soil moisture on the hectare scale. Precise measurements, especially in the case of mobile application, demand for neutron detectors with high counting rates and high signal-to-noise ratios. For a long time Cosmic Ray Neutron Sensing (CRNS) instruments have relied on He-3 as an efficient neutron converter. Its ongoing scarcity demands for technological solutions using alternative converters, which are Li-6 and B-10. Recent developments lead to a modular neutron detector consisting of several B-10-lined proportional counter tubes, which feature high counting rates via its large surface area. The modularity allows for individual shieldings of different segments within the detector featuring the capability of gaining spectral information about the detected neutrons. This opens the possibility for active signal correction, especially useful when applied to mobile measurements, where the influence of constantly changing near-field to the overall signal should be corrected. Furthermore, the signal-to-noise ratio could be increased by combining pulse height and pulse length spectra to discriminate between neutrons and other environmental radiation. This novel detector therefore combines high-selective counting electronics with large-scale instrumentation technology. KW - CRNS KW - neutron KW - detector KW - soil moisture KW - readout electronics KW - boron-10 KW - helium-3 alternative Y1 - 2020 U6 - https://doi.org/10.3389/frwa.2020.00016 SN - 2624-9375 VL - 2 PB - Frontiers Media CY - Lausanne ER - TY - JOUR A1 - Schwanghart, Wolfgang A1 - Scherler, Dirk T1 - Divide mobility controls knickpoint migration on the Roan Plateau (Colorado, USA) JF - Geology N2 - Knickpoints in longitudinal river profiles are proxies for the climatic and tectonic history of active mountains. The analysis of river profiles commonly relies on the assumption that drainage network configurations are stable. Here, we show that this assumption must be made cautiously if changes in contributing area are fast relative to knickpoint migration rates. We studied the Parachute Creek basin in the Roan Plateau, Colorado, United States, where knickpoint retreat occurs in horizontally uniform lithology so that drainage area is the sole governing variable. In this basin, we identified an anomalous catchment in the degree to which a stream power-based model predicted knickpoint locations. The catchment is experiencing area loss as the plateau edge is eroded by cliff migration in proximity to the Colorado River. Model predictions improve if the plateau edge is assumed to have migrated over the time scale of knickpoint retreat. Finally, a Lagrangian model of knickpoint migration enabled us to study the kinematic links between drainage area loss and knickpoint migration and offered constraints on the temporal aspects of area loss. Modeled onset and amount of area loss are consistent with cliff retreat rates along the margin of the Roan Plateau inferred from the incisional history of the upper Colorado River. Y1 - 2020 U6 - https://doi.org/10.1130/G47054.1 SN - 0091-7613 SN - 1943-2682 VL - 48 IS - 7 SP - 698 EP - 702 PB - Geological Society of America CY - Boulder, Colo. ER - TY - JOUR A1 - Heidenreich, Anna A1 - Masson, Torsten A1 - Bamberg, Sebastian T1 - Let’s talk about flood risk BT - evaluating a series of workshops on private flood protection JF - International journal of disaster risk reduction : IJDRR N2 - Private flood protection measures can help reduce potential damage from flooding. Few intervention studies currently exist that systematically evaluate the effectiveness of risk communication methods. To address this gap, we evaluated a series of six workshops (N = 115) on private flood protection in flood-prone areas in Germany that covers different aspects of flood protection for individual households. Applying mixed-model analysis, significant increases in self-efficacy, subjective knowledge, and protection motivation were observed. Younger participants, as well as participants who reported lower levels of previous knowledge or no flood experience, showed a higher increase in self-efficacy and knowledge. Results suggest that a workshop can be an effective risk communication tool, raising awareness and motivating behaviour among residents of flood-prone areas. KW - flooding KW - natural hazard KW - self-efficacy KW - protection motivation theory KW - intervention program Y1 - 2020 U6 - https://doi.org/10.1016/j.ijdrr.2020.101880 SN - 2212-4209 VL - 50 PB - Elsevier CY - Amsterdam [u.a.] ER - TY - JOUR A1 - Natho, Stephanie A1 - Tschikof, Martin A1 - Bondar-Kunze, Elisabeth A1 - Hein, Thomas T1 - Modeling the effect of enhanced lateral connectivity on nutrient retention capacity in large river floodplains BT - how much connected floodplain do we need? JF - Frontiers in Environmental Science N2 - Floodplains have been degraded in Central Europe for centuries, resulting in less dynamic and less diverse ecosystems than in the past. They provide essential ecosystem services like nutrient retention to improve overall water quality and thus fulfill naturally what EU legislation demands, but this service is impaired by reduced connectivity patterns. Along the second-longest river in Europe, the Danube, restoration measures have been carried out and are planned for the near future in the Austrian Danube Floodplain National Park in accordance with navigation purposes. We investigated nutrient retention capacity in seven currently differently connected side arms and the effects of proposed restoration measures using two complementary modeling approaches. We modeled nutrient retention capacity in two scenarios considering different hydrological conditions, as well as the consequences of planned restoration measures for side arm connectivity. With existing monitoring data on hydrology, nitrate, and total phosphorus concentrations for three side arms, we applied a statistical model and compared these results to a semi-empirical retention model. The latter was originally developed for larger scales, based on transferable causalities of retention processes and set up for this floodplain with publicly available data. Both model outcomes are in a comparable range for NO3-N (77-198 kg ha(-1)yr(-1)) and TP (1.4-5.7 kg ha(-1)yr(-1)) retention and agree in calculating higher retention in floodplains, where reconnection allows more frequent inundation events. However, the differences in the model results are significant for specific aspects especially during high flows, where the semi-empirical model complements the statistical model. On the other hand, the statistical model complements the semi-empirical model when taking into account nutrient retention at times of no connection between the remaining water bodies left in the floodplain. Overall, both models show clearly that nutrient retention in the Danube floodplains can be enhanced by restoring lateral hydrological reconnection and, for all planned measures, a positive effect on the overall water quality of the Danube River is expected. Still, a frequently hydrologically connected stretch of national park is insufficient to improve the water quality of the whole Upper Danube, and more functional floodplains are required. KW - floodplain KW - lateral hydrological connectivity KW - Danube KW - restoration KW - reconnection KW - inundation KW - nutrient retention KW - modeling Y1 - 2020 U6 - https://doi.org/10.3389/fenvs.2020.00074 SN - 2296-665X VL - 8 PB - Frontiers Media CY - Lausanne ER - TY - JOUR A1 - Athare, Tushar Ramchandra A1 - Pradhan, Prajal A1 - Kropp, Jürgen T1 - Environmental implications and socioeconomic characterisation of Indian diets JF - The science of the total environment N2 - India is facing a double burden of malnourishment with co-existences of under- and over-nourishment. Various socioeconomic factors play an essential role in determining dietary choices. Agriculture is one of the major emitters of greenhouse gases (GHGs) in India, contributing 18% of total emissions. It also consumes freshwater and uses land significantly. We identify eleven Indian diets by applying k-means cluster analysis on latest data from the Indian household consumer expenditure survey. The diets vary in calorie intake [2289-3218 kcal/Consumer Unit (CU)/day] and dietary composition. Estimated embodied GHG emissions in the diets range from 1.36 to 3.62 kg CO2eq./CU/day, land footprint from 4 to 5.45 m(2)/CU/day, whereas water footprint varies from 2.13 to 2.97m(3)/CU/day. Indian diets deviate from a healthy reference diet either with too much or too little consumption of certain food groups. Overall, cereals, sugar, and dairy products intake are higher. In contrast, the consumption of fruits and vegetables, pulses, and nuts is lower than recommended. Our study contributes to deriving required polices for the sustainable transformation of food systems in India to eliminate malnourishment and to reduce the environmental implications of the food systems. (c) 2020 Elsevier B.V. All rights reserved. KW - Indian diets KW - GHG emissions KW - land and water footprint KW - healthy diets KW - socioeconomic factors Y1 - 2020 U6 - https://doi.org/10.1016/j.scitotenv.2020.139881 SN - 0048-9697 SN - 1879-1026 VL - 737 PB - Elsevier Science CY - Amsterdam [u.a.] ER - TY - JOUR A1 - Korges, Maximilian A1 - Weis, Philipp A1 - Andersen, Christine T1 - The role of incremental magma chamber growth on ore formation in porphyry copper systems JF - Earth & planetary science letters N2 - Porphyry copper deposits are formed by fluids released from felsic magmatic intrusions of batholithic dimensions, which are inferred to have been incrementally built up by a series of sill injections. The growth of the magma chamber is primarily controlled by the volumetric injection rate from deeper-seated magma reservoirs, but can further be influenced by hydrothermal convection and fluid release. To quantify the interplay between magma chamber growth, volatile expulsion and hydrothermal fluid flow during ore formation, we used numerical simulations that can model episodic sill injections in concert with multi-phase fluid flow. To build up a magma chamber that constantly maintains a small region of melt within a period of about 50 kyrs, an injection rate of at least 1.3 x 10(-3) km(3)/y is required. Higher magma influxes of 1.9 to 7.6 x 10(-3) km(3)/y are able to form magma chambers with a thickness of 2 to 3 km. Such an intrusion continuously produces magmatic volatiles which can precipitate a copper ore shell in the host rock about 2 km above the fluid injection location. The steady fluid flux from such an incrementally growing magma chamber maintains a stable magmatic fluid plume, precipitating a copper ore shell in a more confined region and resulting in higher ore grades than the ones generated by an instantaneous emplacement of a voluminous magma chamber. Our simulation results suggest that magma chambers related to porphyry copper deposits form by rapid and episodic injection of magma. Slower magma chamber growth rates more likely result in barren plutonic rocks, although they are geochemically similar to porphyry-hosting plutons. However, these low-frequency sill injection events without a significant magma chamber growth can generate magmatic fluid pulses that can reach the shallow subsurface and are typical for high-sulfidation epithermal deposits. KW - pluton KW - magma chamber KW - porphyry copper deposits KW - magmatic sill KW - numerical modeling KW - ore deposit Y1 - 2020 U6 - https://doi.org/10.1016/j.epsl.2020.116584 SN - 0012-821X SN - 1385-013X VL - 552 PB - Elsevier CY - Amsterdam [u.a.] ER - TY - JOUR A1 - Boergens, Eva A1 - Güntner, Andreas A1 - Dobslaw, Henryk A1 - Dahle, Christoph T1 - Quantifying the Central European droughts in 2018 and 2019 with GRACE Follow-On JF - Geophysical research letters : GRL N2 - The GRACE-FO satellites launched in May 2018 are able to quantify the water mass deficit in Central Europe during the two consecutive summer droughts of 2018 and 2019. Relative to the long-term climatology, the water mass deficits were-112 +/- 10.5 Gt in 2018 and-145 +/- 12 Gt in 2019. These deficits are 73% and 94% of the mean amplitude of seasonal water storage variations, which is so severe that a recovery cannot be expected within 1 year. The water deficits in 2018 and 2019 are the largest in the whole GRACE and GRACE-FO time span. Globally, the data do not show an offset between the two missions, which proves the successful continuation of GRACE by GRACE-FO and thus the reliability of the observed extreme events in Central Europe. This allows for a joint assessment of the four Central European droughts in 2003, 2015, 2018, and 2019 in terms of total water storage deficits. KW - GRACE-FO KW - GRACE KW - drought KW - Central European drought 2018 KW - Central European drought 2019 Y1 - 2020 U6 - https://doi.org/10.1029/2020GL087285 SN - 0094-8276 SN - 1944-8007 VL - 47 IS - 14 PB - American Geophysical Union CY - Washington, DC ER - TY - JOUR A1 - Pätzig, Marlene A1 - Kalettka, Thomas A1 - Onandia, Gabriela A1 - Balla, Dagmar A1 - Lischeid, Gunnar T1 - How much information do we gain from multiple-year sampling in natural pond research? JF - Limnologica : ecology and management of inland waters N2 - Natural ponds are perceived as spatially and temporally highly variable ecosystems. This perception is in contrast to the often-applied sampling design with high spatial but low temporal replication. Based on a data set covering a period of six years and 20 permanently to periodically inundated ponds, we investigated whether this widely applied sampling design is sufficient to identify differences between single ponds or single years with regard to water quality and macrophyte community composition as measures of ecosystem integrity. In our study, the factor "pond", which describes differences between individual ponds, explained 56 % and 63 %, respectively, of the variance in water quality and macrophyte composition. In contrast, the factor "year" that refers to changes between individual years, contributed less to understand the observed variability in water quality and macrophyte composition (10 % and 7 % respectively, of the variance explained). The low explanation of variance for "year" and the low year-to-year correlation for the single water quality parameter or macrophyte coverage values, respectively, indicated high but non-consistent temporal variability affecting individual pond patterns. In general, the results largely supported the ability of the widely applied sampling strategy with about one sampling date per year to capture differences in water quality and macrophyte community composition between ponds. Hence, future research can be rest upon sampling designs that give more weight to the number of ponds than the number of years in dependence on the research question and the available resources. Nonetheless, pond research would miss a substantial amount of information (7 to 10 % of the variance explained), when the sampling would generally be restricted to one year. Moreover, we expect that the importance of multiple-year sampling will likely increase in periods and regions of higher hydrological variability compared to the average hydrological conditions encountered in the studied period. KW - water quality KW - macrophytes KW - space KW - time KW - kettle holes KW - conservation Y1 - 2020 U6 - https://doi.org/10.1016/j.limno.2019.125728 SN - 0075-9511 SN - 1873-5851 VL - 80 PB - Elsevier CY - Amsterdam [u.a.] ER - TY - JOUR A1 - Metin, Ayse Duha A1 - Dung, Nguyen Viet A1 - Schröter, Kai A1 - Vorogushyn, Sergiy A1 - Guse, Björn A1 - Kreibich, Heidi A1 - Merz, Bruno T1 - The role of spatial dependence for large-scale flood risk estimation JF - Natural hazards and earth system sciences N2 - Flood risk assessments are typically based on scenarios which assume homogeneous return periods of flood peaks throughout the catchment. This assumption is unrealistic for real flood events and may bias risk estimates for specific return periods. We investigate how three assumptions about the spatial dependence affect risk estimates: (i) spatially homogeneous scenarios (complete dependence), (ii) spatially heterogeneous scenarios (modelled dependence) and (iii) spatially heterogeneous but uncorrelated scenarios (complete independence). To this end, the model chain RFM (regional flood model) is applied to the Elbe catchment in Germany, accounting for the spatio-temporal dynamics of all flood generation processes, from the rainfall through catchment and river system processes to damage mechanisms. Different assumptions about the spatial dependence do not influence the expected annual damage (EAD); however, they bias the risk curve, i.e. the cumulative distribution function of damage. The widespread assumption of complete dependence strongly overestimates flood damage of the order of 100% for return periods larger than approximately 200 years. On the other hand, for small and medium floods with return periods smaller than approximately 50 years, damage is underestimated. The overestimation aggravates when risk is estimated for larger areas. This study demonstrates the importance of representing the spatial dependence of flood peaks and damage for risk assessments. Y1 - 2020 U6 - https://doi.org/10.5194/nhess-20-967-2020 SN - 1561-8633 SN - 1684-9981 VL - 20 IS - 4 SP - 967 EP - 979 PB - European Geosciences Union (EGU) ; Copernicus CY - Göttingen ER - TY - JOUR A1 - Pradhan, Prajal A1 - Kropp, Jürgen T1 - Interplay between diets, health, and climate change JF - Sustainability N2 - The world is facing a triple burden of undernourishment, obesity, and environmental impacts from agriculture while nourishing its population. This burden makes sustainable nourishment of the growing population a global challenge. Addressing this challenge requires an understanding of the interplay between diets, health, and associated environmental impacts (e.g., climate change). For this, we identify 11 typical diets that represent dietary habits worldwide for the last five decades. Plant-source foods provide most of all three macronutrients (carbohydrates, protein, and fat) in developing countries. In contrast, animal-source foods provide a majority of protein and fat in developed ones. The identified diets deviate from the recommended healthy diet with either too much (e.g., red meat) or too little (e.g., fruits and vegetables) food and nutrition supply. The total calorie supplies are lower than required for two diets. Sugar consumption is higher than recommended for five diets. Three and five diets consist of larger-than-recommended carbohydrate and fat shares, respectively. Four diets with a large share of animal-source foods exceed the recommended value of red meat. Only two diets consist of at least 400 gm/cap/day of fruits and vegetables while accounting for food waste. Prevalence of undernourishment and underweight dominates in the diets with lower calories. In comparison, a higher prevalence of obesity is observed for diets with higher calories with high shares of sugar, fat, and animal-source foods. However, embodied emissions in the diets do not show a clear relation with calorie supplies and compositions. Two high-calorie diets embody more than 1.5 t CO2eq/cap/yr, and two low-calorie diets embody around 1 t CO2eq/cap/yr. Our analysis highlights that sustainable and healthy diets can serve the purposes of both nourishing the population and, at the same time, reducing the environmental impacts of agriculture. KW - dietary patterns KW - healthy diets KW - embodied emissions KW - diet shifts KW - sustainable diets KW - emission intensity Y1 - 2020 U6 - https://doi.org/10.3390/su12093878 SN - 2071-1050 VL - 12 IS - 9 PB - MDPI CY - Basel ER - TY - JOUR A1 - Spooner, Cameron A1 - Scheck-Wenderoth, Magdalena A1 - Cacace, Mauro A1 - Götze, Hans-Jürgen A1 - Luijendijk, Elco T1 - The 3D thermal field across the Alpine orogen and its forelands and the relation to seismicity JF - Global and planetary change N2 - Temperature exerts a first order control on rock strength, principally via thermally activated creep deformation and on the distribution at depth of the brittle-ductile transition zone. The latter can be regarded as the lower bound to the seismogenic zone, thereby controlling the spatial distribution of seismicity within a lithospheric plate. As such, models of the crustal thermal field are important to understand the localisation of seismicity. Here we relate results from 3D simulations of the steady state thermal field of the Alpine orogen and its forelands to the distribution of seismicity in this seismically active area of Central Europe. The model takes into account how the crustal heterogeneity of the region effects thermal properties and is validated with a dataset of wellbore temperatures. We find that the Adriatic crust appears more mafic, through its radiogenic heat values (1.30E-06 W/m3) and maximum temperature of seismicity (600 degrees C), than the European crust (1.3-2.6E-06 W/m3 and 450 degrees C). We also show that at depths of < 10 km the thermal field is largely controlled by sedimentary blanketing or topographic effects, whilst the deeper temperature field is primarily controlled by the LAB topology and the distribution and parameterization of radiogenic heat sources within the upper crust. KW - steady-state KW - thermal-field KW - Europe KW - Alps KW - Adria KW - seismicity Y1 - 2020 U6 - https://doi.org/10.1016/j.gloplacha.2020.103288 SN - 0921-8181 SN - 1872-6364 VL - 193 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Lehr, Christian A1 - Lischeid, Gunnar T1 - Efficient screening of groundwater head monitoring data for anthropogenic effects and measurement errors JF - Hydrology and Earth System Sciences N2 - Groundwater levels are monitored by environmental agencies to support the sustainable use of groundwater resources. For this purpose continuous and spatially comprehensive monitoring in high spatial and temporal resolution is desired. This leads to large datasets that have to be checked for quality and analysed to distinguish local anthropogenic influences from natural variability of the groundwater level dynamics at each well. Both technical problems with the measurements as well as local anthropogenic influences can lead to local anomalies in the hydrographs. We suggest a fast and efficient screening method for the identification of well-specific peculiarities in hydrographs of groundwater head monitoring networks. The only information required is a set of time series of groundwater heads all measured at the same instants of time. For each well of the monitoring network a reference hydrograph is calculated, describing expected "normal" behaviour at the respective well as is typical for the monitored region. The reference hydrograph is calculated by multiple linear regression of the observed hydrograph with the "stable" principal components (PCs) of a principal component analysis of all groundwater head series of the network as predictor variables. The stable PCs are those PCs which were found in a random subsampling procedure to be rather insensitive to the specific selection of the analysed observation wells, i.e. complete series, and to the specific selection of measurement dates. Hence they can be considered to be representative for the monitored region in the respective period. The residuals of the reference hydrograph describe local deviations from the normal behaviour. Peculiarities in the residuals allow the data to be checked for measurement errors and the wells with a possible anthropogenic influence to be identified. The approach was tested with 141 groundwater head time series from the state authority groundwater monitoring network in northeastern Germany covering the period from 1993 to 2013 at an approximately weekly frequency of measurement. KW - streamflow variability KW - principal components KW - united states KW - time-seriesa KW - water KW - network KW - nonstationarity KW - fluctuations KW - rotation Y1 - 2020 U6 - https://doi.org/10.5194/hess-24-501-2020 SN - 1027-5606 SN - 1607-7938 VL - 24 IS - 2 SP - 501 EP - 513 PB - Copernicus CY - Göttingen ER - TY - JOUR A1 - Hudson, Paul A1 - Hagedoorn, Liselotte A1 - Bubeck, Philip T1 - Potential linkages between social capital, flood risk perceptions, and self-efficacy JF - International journal of disaster risk science N2 - A growing focus is being placed on both individuals and communities to adapt to flooding as part of the Sendai Framework for Disaster Risk Reduction 2015-2030. Adaptation to flooding requires sufficient social capital (linkages between members of society), risk perceptions (understanding of risk), and self-efficacy (self-perceived ability to limit disaster impacts) to be effective. However, there is limited understanding of how social capital, risk perceptions, and self-efficacy interact. We seek to explore how social capital interacts with variables known to increase the likelihood of successful adaptation. To study these linkages we analyze survey data of 1010 respondents across two communities in Thua Tien-Hue Province in central Vietnam, using ordered probit models. We find positive correlations between social capital, risk perceptions, and self-efficacy overall. This is a partly contrary finding to what was found in previous studies linking these concepts in Europe, which may be a result from the difference in risk context. The absence of an overall negative exchange between these factors has positive implications for proactive flood risk adaptation. KW - flood risk KW - protection motivation theory KW - risk perceptions KW - social KW - capital KW - self-efficacy KW - Vietnam Y1 - 2020 U6 - https://doi.org/10.1007/s13753-020-00259-w SN - 2095-0055 SN - 2192-6395 VL - 11 IS - 3 SP - 251 EP - 262 PB - Springer CY - Berlin ER - TY - JOUR A1 - Cavael, Ulrike A1 - Diehl, Katharina A1 - Lentzsch, Peter T1 - Assessment of growth suppression in apple production with replant soils JF - Ecological indicators : integrating monitoring, assessment and management N2 - Apple replant disease (ARD) is a specific apple-related form of soil fertility loss due to unidentified causes and is also known as soil fatigue. The effect typically appears in monoculture production sites and leads to production decreases of up to 50%, even though the cultivation practice remains the same. However, an indication of replant disease is challenged by the lack of specification of the particular microbial group responsible for ARD. The objective of this study was to establish an algorithm for estimating growth suppression in orchards irrespective of the unknowns in the complex causal relationship by assessing plant-soil interaction in the orchard several years after planting. Based on a comparison between no-replant and replant soils, the Alternaria group (Ag) was identified as a soil-fungal population responding to replant with abundance. The trunk cross-sectional area (CSA) was found to be a practical and robust parameter representing below-ground and above-ground tree performance. Suppression of tree vigour was therefore calculated by dividing the two inversely related parameters, Q = ln(Ag)/CSA, as a function of soil-fungal proportions and plant responses at the single-tree level. On this basis, five clusters of tree vigour suppression (Q) were defined: (1) no tree vigour suppression/vital (0%), (2) escalating (- 38%), (3) strong (- 53%), (4) very strong (- 62%), and (5) critical (- 74%). By calculating Q at the level of the single tree, trees were clustered according to tree vigour suppression. The weighted frequency of clusters in the field allowed replant impact to be quantified at field level. Applied to a case study on sandy brown, dry diluvial soils in Brandenburg, Germany, the calculated tree vigour suppression was 46% compared to the potential tree vigour on no-replant soil in the same field. It is highly likely that the calculated growth suppression corresponds to ARD-impact This result is relevant for identifying functional changes in soil and for monitoring the economic effects of soil fatigue in apple orchards, particularly where long-period crop rotation or plot exchange are improbable. KW - orchard management KW - trunk cross-sectional area KW - alternaria group KW - apple KW - production KW - soil fatigue KW - apple replant disease Y1 - 2019 U6 - https://doi.org/10.1016/j.ecolind.2019.105846 SN - 1470-160X SN - 1872-7034 VL - 109 PB - Elsevier Science CY - Amsterdam ER - TY - JOUR A1 - Cavael, Ulrike A1 - Diehl, Katharina A1 - Lentzsch, Peter T1 - Assessment of growth suppression in apple production with replant soils JF - Ecological indicators : integrating monitoring, assessment and management N2 - Apple replant disease (ARD) is a specific apple-related form of soil fertility loss due to unidentified causes and is also known as soil fatigue. The effect typically appears in monoculture production sites and leads to production decreases of up to 50%, even though the cultivation practice remains the same. However, an indication of replant disease is challenged by the lack of specification of the particular microbial group responsible for ARD. The objective of this study was to establish an algorithm for estimating growth suppression in orchards irrespective of the unknowns in the complex causal relationship by assessing plant-soil interaction in the orchard several years after planting. Based on a comparison between no-replant and replant soils, the Alternaria group (Ag) was identified as a soil-fungal population responding to replant with abundance. The trunk cross-sectional area (CSA) was found to be a practical and robust parameter representing below-ground and above-ground tree performance. Suppression of tree vigour was therefore calculated by dividing the two inversely related parameters, Q = ln(Ag)/CSA, as a function of soil-fungal proportions and plant responses at the single-tree level. On this basis, five clusters of tree vigour suppression (Q) were defined: (1) no tree vigour suppression/vital (0%), (2) escalating (- 38%), (3) strong (- 53%), (4) very strong (- 62%), and (5) critical (- 74%). By calculating Q at the level of the single tree, trees were clustered according to tree vigour suppression. The weighted frequency of clusters in the field allowed replant impact to be quantified at field level. Applied to a case study on sandy brown, dry diluvial soils in Brandenburg, Germany, the calculated tree vigour suppression was 46% compared to the potential tree vigour on no-replant soil in the same field. It is highly likely that the calculated growth suppression corresponds to ARD-impact This result is relevant for identifying functional changes in soil and for monitoring the economic effects of soil fatigue in apple orchards, particularly where long-period crop rotation or plot exchange are improbable. KW - orchard management KW - trunk cross-sectional area KW - alternaria group KW - apple KW - production KW - soil fatigue KW - apple replant disease Y1 - 2020 U6 - https://doi.org/10.1016/j.ecolind.2019.105846 SN - 1470-160X SN - 1872-7034 VL - 109 PB - Elsevier Science CY - Amsterdam ER - TY - JOUR A1 - Dresen, Georg A1 - Kwiatek, Grzegorz A1 - Goebel, Thomas A1 - Ben-Zion, Yehuda T1 - Seismic and aseismic preparatory processes before large stick-slip failure JF - Pure and applied geophysics N2 - Natural earthquakes often have very few observable foreshocks which significantly complicates tracking potential preparatory processes. To better characterize expected preparatory processes before failures, we study stick-slip events in a series of triaxial compression tests on faulted Westerly granite samples. We focus on the influence of fault roughness on the duration and magnitude of recordable precursors before large stick-slip failure. Rupture preparation in the experiments is detectable over long time scales and involves acoustic emission (AE) and aseismic deformation events. Preparatory fault slip is found to be accelerating during the entire pre-failure loading period, and is accompanied by increasing AE rates punctuated by distinct activity spikes associated with large slip events. Damage evolution across the fault zones and surrounding wall rocks is manifested by precursory decrease of seismic b-values and spatial correlation dimensions. Peaks in spatial event correlation suggest that large slip initiation occurs by failure of multiple asperities. Shear strain estimated from AE data represents only a small fraction (< 1%) of total shear strain accumulated during the preparation phase, implying that most precursory deformation is aseismic. The relative contribution of aseismic deformation is amplified by larger fault roughness. Similarly, seismic coupling is larger for smooth saw-cut faults compared to rough faults. The laboratory observations point towards a long-lasting and continuous preparation process leading to failure and large seismic events. The strain partitioning between aseismic and observable seismic signatures depends on fault structure and instrument resolution. KW - Earthquakes KW - rupture KW - stick–slip tests KW - seismic KW - aseismic Y1 - 2020 U6 - https://doi.org/10.1007/s00024-020-02605-x SN - 0033-4553 SN - 1420-9136 VL - 177 IS - 12 SP - 5741 EP - 5760 PB - Springer CY - Basel ER - TY - JOUR A1 - Barkow, Isolde S. A1 - Oswald, Sascha A1 - Lensing, Hermann Josef A1 - Munz, Matthias T1 - Seasonal dynamics modifies fate of oxygen, nitrate, and organic micropollutants during bank filtration BT - temperature-dependent reactive transport modeling of field data JF - Environmental science and pollution research : official organ of the EuCheMS Division for Chemistry and the Environment, EuCheMS DCE N2 - Bank filtration is considered to improve water quality through microbially mediated degradation of pollutants and is suitable for waterworks to increase their production. In particular, aquifer temperatures and oxygen supply have a great impact on many microbial processes. To investigate the temporal and spatial behavior of selected organic micropollutants during bank filtration in dependence of relevant biogeochemical conditions, we have set up a 2D reactive transport model using MODFLOW and PHT3D under the user interface ORTI3D. The considered 160-m-long transect ranges from the surface water to a groundwater extraction well of the adjacent waterworks. For this purpose, water levels, temperatures, and chemical parameters were regularly measured in the surface water and groundwater observation wells over one and a half years. To simulate the effect of seasonal temperature variations on microbial mediated degradation, we applied an empirical temperature factor, which yields a strong reduction of the degradation rate at groundwater temperatures below 11 degrees C. Except for acesulfame, the considered organic micropollutants are substantially degraded along their subsurface flow paths with maximum degradation rates in the range of 10(-6) mol L-1 s(-1). Preferential biodegradation of phenazone, diclofenac, and valsartan was found under oxic conditions, whereas carbamazepine and sulfamethoxazole were degraded under anoxic conditions. This study highlights the influence of seasonal variations in oxygen supply and temperature on the fate of organic micropollutants in surface water infiltrating into an aquifer. KW - bank filtration KW - aerobic and anaerobic conditions KW - pharmaceuticals and KW - personal care products KW - reactive transport modeling KW - degradation Y1 - 2020 U6 - https://doi.org/10.1007/s11356-020-11002-9 SN - 0944-1344 SN - 1614-7499 VL - 28 IS - 8 SP - 9682 EP - 9700 PB - Springer CY - Heidelberg ER - TY - JOUR A1 - Warchold, Anne A1 - Pradhan, Prajal A1 - Kropp, Jürgen T1 - Variations in sustainable development goal interactions BT - population, regional, and income disaggregation JF - Sustainable development N2 - To fulfill the 2030 Agenda, the complexity of sustainable development goal (SDG) interactions needs to be disentangled. However, this understanding is currently limited. We conduct a cross-sectional correlational analysis for 2016 to understand SDG interactions under the entire development spectrum. We apply several correlation methods to classify the interaction as synergy or trade-off and characterize them according to their monotony and linearity. Simultaneously, we analyze SDG interactions considering population, location, income, and regional groups. Our findings highlight that synergies always outweigh trade-offs and linear outweigh non-linear interactions. SDG 1, 5, and 6 are associated with linear synergies, SDG 3, and 7 with non-linear synergies. SDG interactions vary according to a country's income and region along with the gender, age, and location of its population. In summary, to achieve the 2030 Agenda the detected interactions and inequalities across countries need be tracked and leveraged to "leave no one behind." KW - development pathways KW - disaggregation KW - inequalities KW - non‐ linearity KW - SDG interactions KW - SDGs KW - synergies and trade‐ offs Y1 - 2020 U6 - https://doi.org/10.1002/sd.2145 SN - 0968-0802 SN - 1099-1719 VL - 29 IS - 2 SP - 285 EP - 299 PB - Wiley CY - Hoboken ER - TY - JOUR A1 - Nativ, Ron A1 - Turowski, Jens M. T1 - Site dependence of fluvial incision rate scaling with timescale JF - Journal of geophysical research : Earth surface N2 - Global measurements of incision rate typically show a negative scaling with the timescale over which they were averaged, a phenomenon referred to as the "Sadler effect." This time dependency is thought to result from hiatus periods between incision phases, which leads to a power law scaling of incision rate with timescale. Alternatively, the "Sadler effect" has been argued to be a consequence of the mobility of the modern river bed, where the timescale dependency of incision rates arises from a bias due to the choice of the reference system. In this case, incision rates should be independent of the timescale, provided that the correct reference system is chosen. It is unclear which model best explains the "Sadler effect," and, if a timescale dependency exists, which mathematical formulation can be used to describe it. Here, we present a compilation of 581 bedrock incision rates from 34 studies, averaged over timescales ranging from single floods to millions of years. We constrain the functional relationship between incision rate and timescale and show that time-independent incision rate is inconsistent with the global data. Using a power law dependence, a single constant power is inconsistent with the distribution of observed exponents. Therefore, the scaling exponent is site dependent. Consequently, incision rates measured over contrasting timescales cannot be meaningfully compared between different field sites without properly considering the "Sadler effect." We explore the controls on the variable exponents and propose an empirical equation to correct observed incision rates for their timescale dependency. KW - Sadler effect KW - river incision KW - timescale dependency KW - fluvial incision KW - compilation Y1 - 2020 U6 - https://doi.org/10.1029/2020JF005808 SN - 2169-9003 SN - 2169-9011 VL - 125 IS - 11 PB - American Geophysical Union CY - Washington ER - TY - JOUR A1 - Rottler, Erwin A1 - Francke, Till A1 - Bürger, Gerd A1 - Bronstert, Axel T1 - Long-term changes in central European river discharge for 1869–2016 BT - impact of changing snow covers, reservoir constructions and an intensified hydrological cycle JF - Hydrology and Earth System Sciences N2 - Recent climatic changes have the potential to severely alter river runoff, particularly in snow-dominated river basins. Effects of changing snow covers superimpose with changes in precipitation and anthropogenic modifications of the watershed and river network. In the attempt to identify and disentangle long-term effects of different mechanisms, we employ a set of analytical tools to extract long-term changes in river runoff at high resolution. We combine quantile sampling with moving average trend statistics and empirical mode decomposition and apply these tools to discharge data recorded along rivers with nival, pluvial and mixed flow regimes as well as temperature and precipitation data covering the time frame 1869-2016. With a focus on central Europe, we analyse the long-term impact of snow cover and precipitation changes along with their interaction with reservoir constructions. Our results show that runoff seasonality of snow-dominated rivers decreases. Runoff increases in winter and spring, while discharge decreases in summer and at the beginning of autumn. We attribute this redistribution of annual flow mainly to reservoir constructions in the Alpine ridge. During the course of the last century, large fractions of the Alpine rivers were dammed to produce hydropower. In recent decades, runoff changes induced by reservoir constructions seem to overlap with changes in snow cover. We suggest that Alpine signals propagate downstream and affect runoff far outside the Alpine area in river segments with mixed flow regimes. Furthermore, our results hint at more (intense) rain-fall in recent decades. Detected increases in high discharge can be traced back to corresponding changes in precipitation. KW - empirical mode decomposition KW - atmospheric blocking KW - heavy precipitation KW - streamflow trends KW - climate-change KW - rhine basin KW - time-series KW - events KW - Switzerland KW - variability Y1 - 2020 U6 - https://doi.org/10.5194/hess-24-1721-2020 SN - 1027-5606 SN - 1607-7938 VL - 24 IS - 4 SP - 1721 EP - 1740 PB - Copernicus CY - Göttingen ER - TY - JOUR A1 - Bubeck, Philip A1 - Berghäuser, Lisa A1 - Hudson, Paul A1 - Thieken, Annegret T1 - Using panel data to understand the dynamics of human behavior in response to flooding JF - Risk analysis : an international journal N2 - Insights into the dynamics of human behavior in response to flooding are urgently needed for the development of effective integrated flood risk management strategies, and for integrating human behavior in flood risk modeling. However, our understanding of the dynamics of risk perceptions, attitudes, individual recovery processes, as well as adaptive (i.e., risk reducing) intention and behavior are currently limited because of the predominant use of cross-sectional surveys in the flood risk domain. Here, we present the results from one of the first panel surveys in the flood risk domain covering a relatively long period of time (i.e., four years after a damaging event), three survey waves, and a wide range of topics relevant to the role of citizens in integrated flood risk management. The panel data, consisting of 227 individuals affected by the 2013 flood in Germany, were analyzed using repeated-measures ANOVA and latent class growth analysis (LCGA) to utilize the unique temporal dimension of the data set. Results show that attitudes, such as the respondents' perceived responsibility within flood risk management, remain fairly stable over time. Changes are observed partly for risk perceptions and mainly for individual recovery and intentions to undertake risk-reducing measures. LCGA reveal heterogeneous recovery and adaptation trajectories that need to be taken into account in policies supporting individual recovery and stimulating societal preparedness. More panel studies in the flood risk domain are needed to gain better insights into the dynamics of individual recovery, risk-reducing behavior, and associated risk and protective factors. KW - adaptation behavior KW - floods KW - individual recovery KW - LCGA KW - panel data Y1 - 2020 U6 - https://doi.org/10.1111/risa.13548 SN - 0272-4332 SN - 1539-6924 VL - 40 IS - 11 SP - 2340 EP - 2359 PB - Wiley CY - Hoboken ER - TY - JOUR A1 - Korup, Oliver T1 - Bayesian geomorphology JF - Earth surface processes and landforms : the journal of the British Geomorphological Research Group N2 - The rapidly growing amount and diversity of data are confronting us more than ever with the need to make informed predictions under uncertainty. The adverse impacts of climate change and natural hazards also motivate our search for reliable predictions. The range of statistical techniques that geomorphologists use to tackle this challenge has been growing, but rarely involves Bayesian methods. Instead, many geomorphic models rely on estimated averages that largely miss out on the variability of form and process. Yet seemingly fixed estimates of channel heads, sediment rating curves or glacier equilibrium lines, for example, are all prone to uncertainties. Neighbouring scientific disciplines such as physics, hydrology or ecology have readily embraced Bayesian methods to fully capture and better explain such uncertainties, as the necessary computational tools have advanced greatly. The aim of this article is to introduce the Bayesian toolkit to scientists concerned with Earth surface processes and landforms, and to show how geomorphic models might benefit from probabilistic concepts. I briefly review the use of Bayesian reasoning in geomorphology, and outline the corresponding variants of regression and classification in several worked examples. KW - Bayes' rule KW - probability KW - uncertainty KW - prediction Y1 - 2020 U6 - https://doi.org/10.1002/esp.4995 SN - 0197-9337 SN - 1096-9837 VL - 46 IS - 1 SP - 151 EP - 172 PB - Wiley CY - Hoboken ER - TY - JOUR A1 - Costa Tomaz de Souza, Arthur A1 - Ayzel, Georgy A1 - Heistermann, Maik T1 - Quantifying the location error of precipitation nowcasts JF - Advances in meteorology N2 - In precipitation nowcasting, it is common to track the motion of precipitation in a sequence of weather radar images and to extrapolate this motion into the future. The total error of such a prediction consists of an error in the predicted location of a precipitation feature and an error in the change of precipitation intensity over lead time. So far, verification measures did not allow isolating the extent of location errors, making it difficult to specifically improve nowcast models with regard to location prediction. In this paper, we introduce a framework to directly quantify the location error. To that end, we detect and track scale-invariant precipitation features (corners) in radar images. We then consider these observed tracks as the true reference in order to evaluate the performance (or, inversely, the error) of any model that aims to predict the future location of a precipitation feature. Hence, the location error of a forecast at any lead time Delta t ahead of the forecast time t corresponds to the Euclidean distance between the observed and the predicted feature locations at t + Delta t. Based on this framework, we carried out a benchmarking case study using one year worth of weather radar composites of the German Weather Service. We evaluated the performance of four extrapolation models, two of which are based on the linear extrapolation of corner motion from t - 1 to t (LK-Lin1) and t - 4 to t (LK-Lin4) and the other two are based on the Dense Inverse Search (DIS) method: motion vectors obtained from DIS are used to predict feature locations by linear (DIS-Lin1) and Semi-Lagrangian extrapolation (DIS-Rot1). Of those four models, DIS-Lin1 and LK-Lin4 turned out to be the most skillful with regard to the prediction of feature location, while we also found that the model skill dramatically depends on the sinuosity of the observed tracks. The dataset of 376,125 detected feature tracks in 2016 is openly available to foster the improvement of location prediction in extrapolation-based nowcasting models. KW - inuosity Y1 - 2020 U6 - https://doi.org/10.1155/2020/8841913 SN - 1687-9309 SN - 1687-9317 VL - 2020 PB - Hindawi CY - London ER - TY - JOUR A1 - Koc, Gamze A1 - Petrow, Theresia A1 - Thieken, Annegret T1 - Analysis of the most severe flood events in Turkey (1960-2014) BT - which triggering mechanisms and aggravating pathways can be identified? JF - Water / Molecular Diversity Preservation International (MDPI) N2 - The most severe flood events in Turkey were determined for the period 1960-2014 by considering the number of fatalities, the number of affected people, and the total economic losses as indicators. The potential triggering mechanisms (i.e., atmospheric circulations and precipitation amounts) and aggravating pathways (i.e., topographic features, catchment size, land use types, and soil properties) of these 25 events were analyzed. On this basis, a new approach was developed to identify the main influencing factor per event and to provide additional information for determining the dominant flood occurrence pathways for severe floods. The events were then classified through hierarchical cluster analysis. As a result, six different clusters were found and characterized. Cluster 1 comprised flood events that were mainly influenced by drainage characteristics (e.g., catchment size and shape); Cluster 2 comprised events aggravated predominantly by urbanization; steep topography was identified to be the dominant factor for Cluster 3; extreme rainfall was determined as the main triggering factor for Cluster 4; saturated soil conditions were found to be the dominant factor for Cluster 5; and orographic effects of mountain ranges characterized Cluster 6. This study determined pathway patterns of the severe floods in Turkey with regard to their main causal or aggravating mechanisms. Accordingly, geomorphological properties are of major importance in large catchments in eastern and northeastern Anatolia. In addition, in small catchments, the share of urbanized area seems to be an important factor for the extent of flood impacts. This paper presents an outcome that could be used for future urban planning and flood risk prevention studies to understand the flood mechanisms in different regions of Turkey. KW - hierarchical clustering KW - Hess-Brezowsky Grosswetterlagen classification KW - ERA5 KW - flood hazards KW - pathway KW - Turkey Y1 - 2020 U6 - https://doi.org/10.3390/w12061562 SN - 2073-4441 VL - 12 IS - 6 PB - MDPI CY - Basel ER - TY - JOUR A1 - Herrero, Mario A1 - Thornton, Philip K. A1 - Mason-D'Croz, Daniel A1 - Palmer, Jeda A1 - Bodirsky, Benjamin Leon A1 - Pradhan, Prajal A1 - Barrett, Christopher B. A1 - Benton, Tim G. A1 - Hall, Andrew A1 - Pikaar, Ilje A1 - Bogard, Jessica R. A1 - Bonnett, Graham D. A1 - Bryan, Brett A. A1 - Campbell, Bruce M. A1 - Christensen, Svend A1 - Clark, Michael A1 - Fanzo, Jessica A1 - Godde, Cecile M. A1 - Jarvis, Andy A1 - Loboguerrero, Ana Maria A1 - Mathys, Alexander A1 - McIntyre, C. Lynne A1 - Naylor, Rosamond L. A1 - Nelson, Rebecca A1 - Obersteiner, Michael A1 - Parodi, Alejandro A1 - Popp, Alexander A1 - Ricketts, Katie A1 - Smith, Pete A1 - Valin, Hugo A1 - Vermeulen, Sonja J. A1 - Vervoort, Joost A1 - van Wijk, Mark A1 - van Zanten, Hannah H. E. A1 - West, Paul C. A1 - Wood, Stephen A. A1 - Rockström, Johan T1 - Articulating the effect of food systems innovation on the Sustainable Development Goals JF - The lancet Planetary health N2 - Food system innovations will be instrumental to achieving multiple Sustainable Development Goals (SDGs). However, major innovation breakthroughs can trigger profound and disruptive changes, leading to simultaneous and interlinked reconfigurations of multiple parts of the global food system. The emergence of new technologies or social solutions, therefore, have very different impact profiles, with favourable consequences for some SDGs and unintended adverse side-effects for others. Stand-alone innovations seldom achieve positive outcomes over multiple sustainability dimensions. Instead, they should be embedded as part of systemic changes that facilitate the implementation of the SDGs. Emerging trade-offs need to be intentionally addressed to achieve true sustainability, particularly those involving social aspects like inequality in its many forms, social justice, and strong institutions, which remain challenging. Trade-offs with undesirable consequences are manageable through the development of well planned transition pathways, careful monitoring of key indicators, and through the implementation of transparent science targets at the local level. Y1 - 2020 U6 - https://doi.org/10.1016/S2542-5196(20)30277-1 SN - 2542-5196 VL - 5 IS - 1 SP - E50 EP - E62 PB - Elsevier CY - Oxford ER - TY - JOUR A1 - Liu, Sisi A1 - Stoof-Leichsenring, Kathleen Rosemarie A1 - Kruse, Stefan A1 - Pestryakova, Luidmila Agafyevna A1 - Herzschuh, Ulrike T1 - Holocene vegetation and plant diversity changes in the north-eastern Siberian treeline region from pollen and sedimentary ancient DNA JF - Frontiers in Ecology and Evolution N2 - Although sedimentary ancient DNA (sedaDNA) has been increasingly used to study paleoecological dynamics (Schulte et al., 2020), the approach has rarely been compared with the traditional method of pollen analysis for investigating past changes in the vegetation composition and diversity of Arctic treeline areas. Here, we provide a history of latitudinal floristic composition and species diversity based on a comparison ofsedaDNA and pollen data archived in three Siberian lake sediment cores spanning the mid-Holocene to the present (7.6-0 cal ka BP), from northern typical tundra to southern open larch forest in the Omoloy region. Our results show that thesedaDNA approach identifies more plant taxa found in the local vegetation communities, while the corresponding pollen analysis mainly captures the regional vegetation development and has its limitations for plant diversity reconstruction. Measures of alpha diversity were calculated based onsedaDNA data recovered from along a tundra to forest tundra to open larch forest gradient. Across all sites,sedaDNA archives provide a complementary record of the vegetation transition within each lake's catchment, tracking a distinct latitudinal vegetation type range from larch tree/alder shrub (open larch forest site) to dwarf shrub-steppe (forest tundra) to wet sedge tundra (typical tundra site). By contrast, the pollen data reveal an open landscape, which cannot distinguish the temporal changes in compositional vegetation for the open larch forest site and forest-tundra site. IncreasingLarixpollen percentages were recorded in the forest-tundra site in the last millenium although noLarixDNA was detected, suggesting that thesedaDNA approach performs better for tracking the local establishment ofLarix. Highest species richness and diversity are found in the mid-Holocene (before 4.4 ka) at the typical tundra site with a diverse range of vegetational habitats, while lowest species richness is recorded for the forest tundra where dwarf-willow habitats dominated the lake's catchment. During the late Holocene, strong declines in species richness and diversity are found at the typical tundra site with the vegetation changing to relatively simple communities. Nevertheless, plant species richness is mostly higher than at the forest-tundra site, which shows a slightly decreasing trend. Plant species richness at the open larch forest site fluctuates through time and is higher than the other sites since around 2.5 ka. Taken together, there is no evidence to suggest that the latitudinal gradients in species diversity changes are present at a millennial scale. Additionally, a weak correlation between the principal component analysis (PCA) site scores ofsedaDNA and species richness suggests that climate may not be a direct driver of species turnover within a lake's catchment. Our data suggest thatsedaDNA and pollen have different but complementary abilities for reconstructing past vegetation and species diversity along a latitude. KW - sedimentary ancient DNA KW - metabarcoding KW - pollen KW - Siberia KW - palaeovegetation KW - plant diversity KW - latitudinal gradient Y1 - 2020 U6 - https://doi.org/10.3389/fevo.2020.560243 SN - 2296-701X VL - 8 PB - Frontiers Media CY - Lausanne ER - TY - JOUR A1 - de Brito, Mariana Madruga A1 - Kuhlicke, Christian A1 - Marx, Andreas T1 - Near-real-time drought impact assessment BT - a text mining approach on the 2018/19 drought in Germany JF - Environmental research letters N2 - Contemporary drought impact assessments have been constrained due to data availability, leading to an incomplete representation of impact trends. To address this, we present a novel method for the comprehensive and near-real-time monitoring of drought socio-economic impacts based on media reports. We tested its application using the case of the exceptional 2018/19 German drought. By employing text mining techniques, 4839 impact statements were identified, relating to livestock, agriculture, forestry, fires, recreation, energy and transport sectors. An accuracy of 95.6% was obtained for their automatic classification. Furthermore, high levels of performance in terms of spatial and temporal precision were found when validating our results against independent data (e.g. soil moisture, average precipitation, population interest in droughts, crop yield and forest fire statistics). The findings highlight the applicability of media data for rapidly and accurately monitoring the propagation of drought consequences over time and space. We anticipate our method to be used as a starting point for an impact-based early warning system. KW - drought impacts KW - Germany KW - text analytics KW - newspaper KW - validation Y1 - 2020 U6 - https://doi.org/10.1088/1748-9326/aba4ca SN - 1748-9326 VL - 15 IS - 10 PB - IOP Publ. CY - Bristol ER - TY - JOUR A1 - Pan, Xiaohui A1 - Wang, Weishi A1 - Liu, Tie A1 - Huang, Yue A1 - De Maeyer, Philippe A1 - Guo, Chenyu A1 - Ling, Yunan A1 - Akmalov, Shamshodbek T1 - Quantitative detection and attribution of groundwater level variations in the Amu Darya Delta JF - Water N2 - In the past few decades, the shrinkage of the Aral Sea is one of the biggest ecological catastrophes caused by human activity. To quantify the joint impact of both human activities and climate change on groundwater, the spatiotemporal groundwater dynamic characteristics in the Amu Darya Delta of the Aral Sea from 1999 to 2017 were analyzed, using the groundwater level, climate conditions, remote sensing data, and irrigation information. Statistics analysis was adopted to analyze the trend of groundwater variation, including intensity, periodicity, spatial structure, while the Pearson correlation analysis and principal component analysis (PCA) were used to quantify the impact of climate change and human activities on the variabilities of the groundwater level. Results reveal that the local groundwater dynamic has varied considerably. From 1999 to 2002, the groundwater level dropped from -189 cm to -350 cm. Until 2017, the groundwater level rose back to -211 cm with fluctuation. Seasonally, the fluctuation period of groundwater level and irrigation water was similar, both were about 18 months. Spatially, the groundwater level kept stable within the irrigation area and bare land but fluctuated drastically around the irrigation area. The Pearson correlation analysis reveals that the dynamic of the groundwater level is closely related to irrigation activity within the irrigation area (Nukus: -0.583), while for the place adjacent to the Aral Sea, the groundwater level is closely related to the Large Aral Sea water level (Muynak: 0.355). The results of PCA showed that the cumulative contribution rate of the first three components exceeds 85%. The study reveals that human activities have a great impact on groundwater, effective management, and the development of water resources in arid areas is an essential prerequisite for ecological protection. KW - groundwater level variation KW - climate change KW - human activities KW - statistical analysis KW - Amu Darya Delta Y1 - 2020 U6 - https://doi.org/10.3390/w12102869 SN - 2073-4441 VL - 12 IS - 10 PB - MDPI CY - Basel ER -