@article{Jessel2002, author = {Jessel, Beate}, title = {"Gute fachliche Praxis" in Brandenburgs Landwirtschaft}, year = {2002}, language = {de} } @article{Szaramowicz2004, author = {Szaramowicz, Martin}, title = {"Hierarchy" und "Scale" : Interessante Denkmuster f{\"u}r die Landschaftsplanung?}, year = {2004}, abstract = {Theoretische Ans{\"a}tze unter den Oberbegriffen "Hierarchy" und "Scale" sind in der {\"O}kologie seit den 1980er-Jahren entwickelt und intensiv diskutiert worden. Das wissenschaftliche Paradigma kann mit dem Begriff "Hierarchical Patch Dynamics" beschrieben werden. Obwohl auch Anwendungsbez{\"u}ge diskutiert und konzipiert wurden, hat es in Deutschland bisher in der Landschaftsplanung kein gr{\"o}ßeres Echo hervorgerufen. Gleichwohl gibt es eine Reihe interessanter Ankn{\"u}pfungspunkte zwischen Aussagen der {\"o}kologischen Hierarchie-Theorie und konkreten landschaftsplanerischen und naturschutzfachliceh Aufgabenstellungen. Vor diesem Hintergrund werden Grundz{\"u}ge dieser Theorie bzw. der unter dem Dach des Paradigmas "Hierarchical Patch Dynamics" versammelten theoretischen Ans{\"a}tze dargestellt. Wesentlich ist die erkenntnistheoretische Grundhaltung, die versucht, unzul{\"a}ssige Verallgemeinerungen oder Absolutheitsanspr{\"u}che auszuschließen, indem sie zun{\"a}chst den Gegenstandsbereich der {\"O}kologie beschreibt und analysiert. Auf dieser Grundlage werden Herangehensweisen zur Behandlung {\"o}kologischer Fragestellungen vorgeschlagen. Diese Herangehensweisen lassen sich auf landschaftsplanerische Aufgaben {\"u}bertragen. Es wird gezeigt, f{\"u}r welche Bereiche eine solche {\"U}bertragung denkbar w{\"a}re. Letztlich bed{\"u}rfte es einer Praxis{\"u}berpr{\"u}fung, um herauszufinden, ob mit Hilfe von Ans{\"a}tzen der {\"o}kologischen Hierarchie- Theorie die Bearbeitung planerischer Fragestellungen verbessert oder erg{\"a}nzt werden k{\"o}nnte.}, language = {de} } @incollection{Brendel2019, author = {Brendel, Nina}, title = {(How) do students reflect on sustainability?}, series = {Issues in Teaching and Learning of Education for Sustainability}, booktitle = {Issues in Teaching and Learning of Education for Sustainability}, editor = {Chang, Chew-Hung and Kidman, Gillian and Wi, Andy}, publisher = {Routledge}, address = {Abingdon}, isbn = {978-0-429-45043-3}, doi = {10.4324/9780429450433}, pages = {117 -- 126}, year = {2019}, abstract = {The ability to reflect is considered an essential element of Education for Sustainable Development (ESD) and a key competence for learners and educators in ESD (UNECE Strategy for ESD, 2012). In contrast to its high importance, little is known about how reflective thinking can be identified, influenced or increased in the classroom. Therefore, the objective of this study is to address this need by developing an empirical multi-stage model designed to help educators diagnose different levels of reflective thinking and to identify factors that influence students' reflective thinking about sustainability. Based on a 4-8-week project with grade 10 and 11 students studying sustainability, reflective thinking performance using weblogs as reflective journals was analysed. In addition, qualitative semi-structured interviews were conducted with the teachers to comprehend the learning environment and the personal value they assigned to ESD in their geography class. To determine the levels of reflective thinking achieved by the students, the study built on the work of Dewey (1933) and pre-existing multi-stage models of reflective thinking (Bain, Ballantyne, \& Packer, 1999; Chen, Wei, Wu, \& Uden, 2009). Using a qualitative, iterative data analysis, the study adapted the stage models to be applicable in ESD and found great differences in the students' reflection levels. Furthermore, the study identified eight factors that influence students' reflective thinking about sustainability. The outcomes of this study may be valuable for educators in high school and higher education, who seek to diagnose their students' reflective thinking performance and facilitate reflection about sustainability.}, language = {en} } @article{Rolfes2008, author = {Rolfes, Manfred}, title = {(Un-)Sicherheit, Risiko und Stadt : neue Ans{\"a}tze in der Stadtentwicklung}, issn = {0171-5178}, year = {2008}, language = {de} } @article{GomezGarciaMeessenScheckWenderothetal.2019, author = {Gomez-Garcia, Angela Maria and Meeßen, Christian and Scheck-Wenderoth, Magdalena and Monsalve, Gaspar and Bott, Judith and Bernhardt, Anne and Bernal, Gladys}, title = {3-D Modeling of Vertical Gravity Gradients and the Delimitation of Tectonic Boundaries: The Caribbean Oceanic Domain as a Case Study}, series = {Geochemistry, geophysics, geosystems}, volume = {20}, journal = {Geochemistry, geophysics, geosystems}, number = {11}, publisher = {American Geophysical Union}, address = {Washington}, issn = {1525-2027}, doi = {10.1029/2019GC008340}, pages = {5371 -- 5393}, year = {2019}, abstract = {Geophysical data acquisition in oceanic domains is challenging, implying measurements with low and/or nonhomogeneous spatial resolution. The evolution of satellite gravimetry and altimetry techniques allows testing 3-D density models of the lithosphere, taking advantage of the high spatial resolution and homogeneous coverage of satellites. However, it is not trivial to discretise the source of the gravity field at different depths. Here, we propose a new method for inferring tectonic boundaries at the crustal level. As a novelty, instead of modeling the gravity anomalies and assuming a flat Earth approximation, we model the vertical gravity gradients (VGG) in spherical coordinates, which are especially sensitive to density contrasts in the upper layers of the Earth. To validate the methodology, the complex oceanic domain of the Caribbean region is studied, which includes different crustal domains with a tectonic history since Late Jurassic time. After defining a lithospheric starting model constrained by up-to-date geophysical data sets, we tested several a-priory density distributions and selected the model with the minimum misfits with respect to the VGG calculated from the EIGEN-6C4 data set. Additionally, the density of the crystalline crust was inferred by inverting the VGG field. Our methodology enabled us not only to refine, confirm, and/or propose tectonic boundaries in the study area but also to identify a new anomalous buoyant body, located in the South Lesser Antilles subduction zone, and high-density bodies along the Greater, Lesser, and Leeward Antilles forearcs.}, language = {en} } @article{BrellSeglGuanteretal.2019, author = {Brell, Maximilian and Segl, Karl and Guanter, Luis and Bookhagen, Bodo}, title = {3D hyperspectral point cloud generation}, series = {ISPRS journal of photogrammetry and remote sensing : official publication of the International Society for Photogrammetry and Remote Sensing}, volume = {149}, journal = {ISPRS journal of photogrammetry and remote sensing : official publication of the International Society for Photogrammetry and Remote Sensing}, publisher = {Elsevier}, address = {Amsterdam}, issn = {0924-2716}, doi = {10.1016/j.isprsjprs.2019.01.022}, pages = {200 -- 214}, year = {2019}, abstract = {Remote Sensing technologies allow to map biophysical, biochemical, and earth surface parameters of the land surface. Of especial interest for various applications in environmental and urban sciences is the combination of spectral and 3D elevation information. However, those two data streams are provided separately by different instruments, namely airborne laser scanner (ALS) for elevation and a hyperspectral imager (HSI) for high spectral resolution data. The fusion of ALS and HSI data can thus lead to a single data entity consistently featuring rich structural and spectral information. In this study, we present the application of fusing the first pulse return information from ALS data at a sub-decimeter spatial resolution with the lower-spatial resolution hyperspectral information available from the HSI into a hyperspectral point cloud (HSPC). During the processing, a plausible hyperspectral spectrum is assigned to every first-return ALS point. We show that the complementary implementation of spectral and 3D information at the point-cloud scale improves object-based classification and information extraction schemes. This improvements have great potential for numerous land cover mapping and environmental applications.}, language = {en} } @article{CostaBronstertdeAraujo2012, author = {Costa, A. C. and Bronstert, Axel and de Araujo, Jose Carlos}, title = {A channel transmission losses model for different dryland rivers}, series = {Hydrology and earth system sciences : HESS}, volume = {16}, journal = {Hydrology and earth system sciences : HESS}, number = {4}, publisher = {Copernicus}, address = {G{\"o}ttingen}, issn = {1027-5606}, doi = {10.5194/hess-16-1111-2012}, pages = {1111 -- 1135}, year = {2012}, abstract = {Channel transmission losses in drylands take place normally in extensive alluvial channels or streambeds underlain by fractured rocks. They can play an important role in streamflow rates, groundwater recharge, freshwater supply and channel-associated ecosystems. We aim to develop a process-oriented, semi-distributed channel transmission losses model, using process formulations which are suitable for data-scarce dryland environments and applicable to both hydraulically disconnected losing streams and hydraulically connected losing(/gaining) streams. This approach should be able to cover a large variation in climate and hydro-geologic controls, which are typically found in dryland regions of the Earth. Our model was first evaluated for a losing/gaining, hydraulically connected 30 km reach of the Middle Jaguaribe River (MJR), Ceara, Brazil, which drains a catchment area of 20 000 km(2). Secondly, we applied it to a small losing, hydraulically disconnected 1.5 km channel reach in the Walnut Gulch Experimental Watershed (WGEW), Arizona, USA. The model was able to predict reliably the streamflow volume and peak for both case studies without using any parameter calibration procedure. We have shown that the evaluation of the hypotheses on the dominant hydrological processes was fundamental for reducing structural model uncertainties and improving the streamflow prediction. For instance, in the case of the large river reach (MJR), it was shown that both lateral stream-aquifer water fluxes and groundwater flow in the underlying alluvium parallel to the river course are necessary to predict streamflow volume and channel transmission losses, the former process being more relevant than the latter. Regarding model uncertainty, it was shown that the approaches, which were applied for the unsaturated zone processes (highly nonlinear with elaborate numerical solutions), are much more sensitive to parameter variability than those approaches which were used for the saturated zone (mathematically simple water budgeting in aquifer columns, including backwater effects). In case of the MJR-application, we have seen that structural uncertainties due to the limited knowledge of the subsurface saturated system interactions (i.e. groundwater coupling with channel water; possible groundwater flow parallel to the river) were more relevant than those related to the subsurface parameter variability. In case of the WEGW application we have seen that the non-linearity involved in the unsaturated flow processes in disconnected dryland river systems (controlled by the unsaturated zone) generally contain far more model uncertainties than do connected systems controlled by the saturated flow. Therefore, the degree of aridity of a dryland river may be an indicator of potential model uncertainty and subsequent attainable predictability of the system.}, language = {en} } @article{MacdonaldOteroButler2021, author = {Macdonald, Elena and Otero, Noelia and Butler, Tim}, title = {A comparison of long-term trends in observations and emission inventories of NOx}, series = {Atmospheric chemistry and physics / European Geosciences Union}, volume = {21}, journal = {Atmospheric chemistry and physics / European Geosciences Union}, number = {5}, publisher = {Copernicus}, address = {G{\"o}ttingen}, issn = {1680-7316}, doi = {10.5194/acp-21-4007-2021}, pages = {4007 -- 4023}, year = {2021}, abstract = {Air pollution is a pressing issue that is associated with adverse effects on human health, ecosystems, and climate. Despite many years of effort to improve air quality, nitrogen dioxide (NO2) limit values are still regularly exceeded in Europe, particularly in cities and along streets. This study explores how concentrations of nitrogen oxides (NOx = NO + NO2) in European urban areas have changed over the last decades and how this relates to changes in emissions. To do so, the incremental approach was used, comparing urban increments (i.e. urban background minus rural concentrations) to total emissions, and roadside increments (i.e. urban roadside concentrations minus urban background concentrations) to traffic emissions. In total, nine European cities were assessed. The study revealed that potentially confounding factors like the impact of urban pollution at rural monitoring sites through atmospheric transport are generally negligible for NOx. The approach proves therefore particularly useful for this pollutant. The estimated urban increments all showed downward trends, and for the majority of the cities the trends aligned well with the total emissions. However, it was found that factors like a very densely populated surrounding or local emission sources in the rural area such as shipping traffic on inland waterways restrict the application of the approach for some cities. The roadside increments showed an overall very diverse picture in their absolute values and trends and also in their relation to traffic emissions. This variability and the discrepancies between roadside increments and emissions could be attributed to a combination of local influencing factors at the street level and different aspects introducing inaccuracies to the trends of the emis-sion inventories used, including deficient emission factors. Applying the incremental approach was evaluated as useful for long-term pan-European studies, but at the same time it was found to be restricted to certain regions and cities due to data availability issues. The results also highlight that using emission inventories for the prediction of future health impacts and compliance with limit values needs to consider the distinct variability in the concentrations not only across but also within cities.}, language = {en} } @article{AgarwalGuntuBanerjeeetal.2022, author = {Agarwal, Ankit and Guntu, Ravikumar and Banerjee, Abhirup and Gadhawe, Mayuri Ashokrao and Marwan, Norbert}, title = {A complex network approach to study the extreme precipitation patterns in a river basin}, series = {Chaos : an interdisciplinary journal of nonlinear science}, volume = {32}, journal = {Chaos : an interdisciplinary journal of nonlinear science}, number = {1}, publisher = {American Institute of Physics}, address = {Woodbury, NY}, issn = {1054-1500}, doi = {10.1063/5.0072520}, pages = {12}, year = {2022}, abstract = {The quantification of spatial propagation of extreme precipitation events is vital in water resources planning and disaster mitigation. However, quantifying these extreme events has always been challenging as many traditional methods are insufficient to capture the nonlinear interrelationships between extreme event time series. Therefore, it is crucial to develop suitable methods for analyzing the dynamics of extreme events over a river basin with a diverse climate and complicated topography. Over the last decade, complex network analysis emerged as a powerful tool to study the intricate spatiotemporal relationship between many variables in a compact way. In this study, we employ two nonlinear concepts of event synchronization and edit distance to investigate the extreme precipitation pattern in the Ganga river basin. We use the network degree to understand the spatial synchronization pattern of extreme rainfall and identify essential sites in the river basin with respect to potential prediction skills. The study also attempts to quantify the influence of precipitation seasonality and topography on extreme events. The findings of the study reveal that (1) the network degree is decreased in the southwest to northwest direction, (2) the timing of 50th percentile precipitation within a year influences the spatial distribution of degree, (3) the timing is inversely related to elevation, and (4) the lower elevation greatly influences connectivity of the sites. The study highlights that edit distance could be a promising alternative to analyze event-like data by incorporating event time and amplitude and constructing complex networks of climate extremes.}, language = {en} } @phdthesis{Koc2021, author = {Ko{\c{c}}, Gamze}, title = {A comprehensive analysis of severe flood events in Turkey}, doi = {10.25932/publishup-51785}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-517853}, school = {Universit{\"a}t Potsdam}, pages = {209}, year = {2021}, abstract = {Over the past decades, natural hazards, many of which are aggravated by climate change and reveal an increasing trend in frequency and intensity, have caused significant human and economic losses and pose a considerable obstacle to sustainable development. Hence, dedicated action toward disaster risk reduction is needed to understand the underlying drivers and create efficient risk mitigation plans. Such action is requested by the Sendai Framework for Disaster Risk Reduction 2015-2030 (SFDRR), a global agreement launched in 2015 that establishes stating priorities for action, e.g. an improved understanding of disaster risk. Turkey is one of the SFDRR contracting countries and has been severely affected by many natural hazards, in particular earthquakes and floods. However, disproportionately little is known about flood hazards and risks in Turkey. Therefore, this thesis aims to carry out a comprehensive analysis of flood hazards for the first time in Turkey from triggering drivers to impacts. It is intended to contribute to a better understanding of flood risks, improvements of flood risk mitigation and the facilitated monitoring of progress and achievements while implementing the SFDRR. In order to investigate the occurrence and severity of flooding in comparison to other natural hazards in Turkey and provide an overview of the temporal and spatial distribution of flood losses, the Turkey Disaster Database (TABB) was examined for the years 1960-2014. The TABB database was reviewed through comparison with the Emergency Events Database (EM-DAT), the Dartmouth Flood Observatory database, the scientific literature and news archives. In addition, data on the most severe flood events between 1960 and 2014 were retrieved. These served as a basis for analyzing triggering mechanisms (i.e. atmospheric circulation and precipitation amounts) and aggravating pathways (i.e. topographic features, catchment size, land use types and soil properties). For this, a new approach was developed and the events were classified using hierarchical cluster analyses to identify the main influencing factor per event and provide additional information about the dominant flood pathways for severe floods. The main idea of the study was to start with the event impacts based on a bottom-up approach and identify the causes that created damaging events, instead of applying a model chain with long-term series as input and searching for potentially impacting events as model outcomes. However, within the frequency analysis of the flood-triggering circulation pattern types, it was discovered that events in terms of heavy precipitation were not included in the list of most severe floods, i.e. their impacts were not recorded in national and international loss databases but were mentioned in news archives and reported by the Turkish State Meteorological Service. This finding challenges bottom-up modelling approaches and underlines the urgent need for consistent event and loss documentation. Therefore, as a next step, the aim was to enhance the flood loss documentation by calibrating, validating and applying the United Nations Office for Disaster Risk Reduction (UNDRR) loss estimation method for the recent severe flood events (2015-2020). This provided, a consistent flood loss estimation model for Turkey, allowing governments to estimate losses as quickly as possible after events, e.g. to better coordinate financial aid. This thesis reveals that, after earthquakes, floods have the second most destructive effects in Turkey in terms of human and economic impacts, with over 800 fatalities and US\$ 885.7 million in economic losses between 1960 and 2020, and that more attention should be paid on the national scale. The clustering results of the dominant flood-producing mechanisms (e.g. circulation pattern types, extreme rainfall, sudden snowmelt) present crucial information regarding the source and pathway identification, which can be used as base information for hazard identification in the preliminary risk assessment process. The implementation of the UNDRR loss estimation model shows that the model with country-specific parameters, calibrated damage ratios and sufficient event documentation (i.e. physically damaged units) can be recommended in order to provide first estimates of the magnitude of direct economic losses, even shortly after events have occurred, since it performed well when estimates were compared to documented losses. The presented results can contribute to improving the national disaster loss database in Turkey and thus enable a better monitoring of the national progress and achievements with regard to the targets stated by the SFDRR. In addition, the outcomes can be used to better characterize and classify flood events. Information on the main underlying factors and aggravating flood pathways further supports the selection of suitable risk reduction policies. All input variables used in this thesis were obtained from publicly available data. The results are openly accessible and can be used for further research. As an overall conclusion, it can be stated that consistent loss data collection and better event documentation should gain more attention for a reliable monitoring of the implementation of the SFDRR. Better event documentation should be established according to a globally accepted standard for disaster classification and loss estimation in Turkey. Ultimately, this enables stakeholders to create better risk mitigation actions based on clear hazard definitions, flood event classification and consistent loss estimations.}, language = {en} } @article{BaroniSchalgeRakovecetal.2019, author = {Baroni, Gabriele and Schalge, Bernd and Rakovec, Oldrich and Kumar, Rohini and Sch{\"u}ler, Lennart and Samaniego, Luis and Simmer, Clemens and Attinger, Sabine}, title = {A Comprehensive Distributed Hydrological Modeling Intercomparison to Support Process Representation and Data Collection Strategies}, series = {Water resources research}, volume = {55}, journal = {Water resources research}, number = {2}, publisher = {American Geophysical Union}, address = {Washington}, issn = {0043-1397}, doi = {10.1029/2018WR023941}, pages = {990 -- 1010}, year = {2019}, abstract = {The improvement of process representations in hydrological models is often only driven by the modelers' knowledge and data availability. We present a comprehensive comparison between two hydrological models of different complexity that is developed to support (1) the understanding of the differences between model structures and (2) the identification of the observations needed for model assessment and improvement. The comparison is conducted on both space and time and by aggregating the outputs at different spatiotemporal scales. In the present study, mHM, a process-based hydrological model, and ParFlow-CLM, an integrated subsurface-surface hydrological model, are used. The models are applied in a mesoscale catchment in Germany. Both models agree in the simulated river discharge at the outlet and the surface soil moisture dynamics, lending their supports for some model applications (drought monitoring). Different model sensitivities are, however, found when comparing evapotranspiration and soil moisture at different soil depths. The analysis supports the need of observations within the catchment for model assessment, but it indicates that different strategies should be considered for the different variables. Evapotranspiration measurements are needed at daily resolution across several locations, while highly resolved spatially distributed observations with lower temporal frequency are required for soil moisture. Finally, the results show the impact of the shallow groundwater system simulated by ParFlow-CLM and the need to account for the related soil moisture redistribution. Our comparison strategy can be applied to other models types and environmental conditions to strengthen the dialog between modelers and experimentalists for improving process representations in Earth system models.}, language = {en} } @article{Buerger2022, author = {B{\"u}rger, Gerd}, title = {A conundrum of trends}, series = {Journal of hydrology}, volume = {609}, journal = {Journal of hydrology}, publisher = {Elsevier}, address = {Amsterdam}, issn = {0022-1694}, doi = {10.1016/j.jhydrol.2022.127745}, pages = {3}, year = {2022}, abstract = {This comment is meant to reiterate two warnings: One applies to the uncritical use of ready-made (openly available) program packages, and one to the estimation of trends in serially correlated time series. Both warnings apply to the recent publication of Lischeid et al. about lake-level trends in Germany.}, language = {en} } @article{ZechAttingerBellinetal.2019, author = {Zech, Alraune and Attinger, Sabine and Bellin, Alberto and Cvetkovic, Vladimir and Dietrich, Peter and Fiori, Aldo and Teutsch, Georg and Dagan, Gedeon}, title = {A Critical Analysis of Transverse Dispersivity Field Data}, series = {Groundwater : journal of the Association of Ground-Water Scientists and Engineers, a division of the National Ground Water Association}, volume = {57}, journal = {Groundwater : journal of the Association of Ground-Water Scientists and Engineers, a division of the National Ground Water Association}, number = {4}, publisher = {Wiley}, address = {Hoboken}, issn = {0017-467X}, doi = {10.1111/gwat.12838}, pages = {632 -- 639}, year = {2019}, abstract = {Transverse dispersion, or tracer spreading orthogonal to the mean flow direction, which is relevant e.g, for quantifying bio-degradation of contaminant plumes or mixing of reactive solutes, has been studied in the literature less than the longitudinal one. Inferring transverse dispersion coefficients from field experiments is a difficult and error-prone task, requiring a spatial resolution of solute plumes which is not easily achievable in applications. In absence of field data, it is a questionable common practice to set transverse dispersivities as a fraction of the longitudinal one, with the ratio 1/10 being the most prevalent. We collected estimates of field-scale transverse dispersivities from existing publications and explored possible scale relationships as guidance criteria for applications. Our investigation showed that a large number of estimates available in the literature are of low reliability and should be discarded from further analysis. The remaining reliable estimates are formation-specific, span three orders of magnitude and do not show any clear scale-dependence on the plume traveled distance. The ratios with the longitudinal dispersivity are also site specific and vary widely. The reliability of transverse dispersivities depends significantly on the type of field experiment and method of data analysis. In applications where transverse dispersion plays a significant role, inference of transverse dispersivities should be part of site characterization with the transverse dispersivity estimated as an independent parameter rather than related heuristically to longitudinal dispersivity.}, language = {en} } @misc{ElsenbeerCasselTinner1993, author = {Elsenbeer, Helmut and Cassel, Keith and Tinner, W.}, title = {A daily rainfall erosivity model for Western Amazonia}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-16962}, year = {1993}, abstract = {Rainfall erosivities as defined by the R factor from the universal soil loss equation were determined for all events during a two-year period at the station La Cuenca in western Amazonia. Three methods based on a power relationship between rainfall amount and erosivity were then applied to estimate event and daily rainfall erosivities from the respective rainfall amounts. A test of the resulting regression equations against an independent data set proved all three methods equally adequate in predicting rainfall erosivity from daily rainfall amount. We recommend the Richardson model for testing in the Amazon Basin, and its use with the coefficient from La Cuenca in western Amazonia.}, language = {en} } @misc{DietzeOeztuerk2021, author = {Dietze, Michael and {\"O}zt{\"u}rk, Ugur}, title = {A flood of disaster response challenges}, series = {Science}, volume = {373}, journal = {Science}, number = {6561}, publisher = {American Association for the Advancement of Science}, address = {Washington}, issn = {0036-8075}, doi = {10.1126/science.abm0617}, pages = {1317 -- 1318}, year = {2021}, language = {en} } @article{BronstertGuentner2000, author = {Bronstert, Axel and G{\"u}ntner, Andreas}, title = {A large-scale hydrological model for the semi-arid environment of north-eastern Brazil}, year = {2000}, language = {en} } @article{YuanBraunGueritetal.2019, author = {Yuan, Xiaoping P. and Braun, Jean and Guerit, Laure and Rouby, D. and Cordonnier, G.}, title = {A New Efficient Method to Solve the Stream Power Law Model Taking Into Account Sediment Deposition}, series = {Journal of geophysical research : Earth surface}, volume = {124}, journal = {Journal of geophysical research : Earth surface}, number = {6}, publisher = {American Geophysical Union}, address = {Washington}, issn = {2169-9003}, doi = {10.1029/2018JF004867}, pages = {1346 -- 1365}, year = {2019}, abstract = {The stream power law model has been widely used to represent erosion by rivers but does not take into account the role played by sediment in modulating erosion and deposition rates. Davy and Lague (2009, ) provide an approach to address this issue, but it is computationally demanding because the local balance between erosion and deposition depends on sediment flux resulting from net upstream erosion. Here, we propose an efficient (i.e., O(N) and implicit) method to solve their equation. This means that, unlike other methods used to study the complete dynamics of fluvial systems (e.g., including the transition from detachment-limited to transport-limited behavior), our method is unconditionally stable even when large time steps are used. We demonstrate its applicability by performing a range of simulations based on a simple setup composed of an uplifting region adjacent to a stable foreland basin. As uplift and erosion progress, the mean elevations of the uplifting relief and the foreland increase, together with the average slope in the foreland. Sediments aggrade in the foreland and prograde to reach the base level where sediments are allowed to leave the system. We show how the topography of the uplifting relief and the stratigraphy of the foreland basin are controlled by the efficiency of river erosion and the efficiency of sediment transport by rivers. We observe the formation of a steady-state geometry in the uplifting region, and a dynamic steady state (i.e., autocyclic aggradation and incision) in the foreland, with aggradation and incision thicknesses up to tens of meters.}, language = {en} } @article{VoitHeistermann2022, author = {Voit, Paul and Heistermann, Maik}, title = {A new index to quantify the extremeness of precipitation across scales}, series = {NHESS - Natural Hazards and Earth System Sciences}, volume = {22}, journal = {NHESS - Natural Hazards and Earth System Sciences}, edition = {8}, publisher = {Copernicus}, address = {Katlenburg-Lindau}, issn = {1684-9981}, doi = {10.5194/nhess-22-2791-2022}, pages = {2791 -- 2805}, year = {2022}, abstract = {Quantifying the extremeness of heavy precipitation allows for the comparison of events. Conventional quantitative indices, however, typically neglect the spatial extent or the duration, while both are important to understand potential impacts. In 2014, the weather extremity index (WEI) was suggested to quantify the extremeness of an event and to identify the spatial and temporal scale at which the event was most extreme. However, the WEI does not account for the fact that one event can be extreme at various spatial and temporal scales. To better understand and detect the compound nature of precipitation events, we suggest complementing the original WEI with a "cross-scale weather extremity index" (xWEI), which integrates extremeness over relevant scales instead of determining its maximum. Based on a set of 101 extreme precipitation events in Germany, we outline and demonstrate the computation of both WEI and xWEI. We find that the choice of the index can lead to considerable differences in the assessment of past events but that the most extreme events are ranked consistently, independently of the index. Even then, the xWEI can reveal cross-scale properties which would otherwise remain hidden. This also applies to the disastrous event from July 2021, which clearly outranks all other analyzed events with regard to both WEI and xWEI. While demonstrating the added value of xWEI, we also identify various methodological challenges along the required computational workflow: these include the parameter estimation for the extreme value distributions, the definition of maximum spatial extent and temporal duration, and the weighting of extremeness at different scales. These challenges, however, also represent opportunities to adjust the retrieval of WEI and xWEI to specific user requirements and application scenarios.}, language = {en} } @misc{VoitHeistermann2022, author = {Voit, Paul and Heistermann, Maik}, title = {A new index to quantify the extremeness of precipitation across scales}, series = {Zweitver{\"o}ffentlichungen der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe}, journal = {Zweitver{\"o}ffentlichungen der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe}, number = {1283}, issn = {1866-8372}, doi = {10.25932/publishup-57089}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-570893}, pages = {2791 -- 2805}, year = {2022}, abstract = {Quantifying the extremeness of heavy precipitation allows for the comparison of events. Conventional quantitative indices, however, typically neglect the spatial extent or the duration, while both are important to understand potential impacts. In 2014, the weather extremity index (WEI) was suggested to quantify the extremeness of an event and to identify the spatial and temporal scale at which the event was most extreme. However, the WEI does not account for the fact that one event can be extreme at various spatial and temporal scales. To better understand and detect the compound nature of precipitation events, we suggest complementing the original WEI with a "cross-scale weather extremity index" (xWEI), which integrates extremeness over relevant scales instead of determining its maximum. Based on a set of 101 extreme precipitation events in Germany, we outline and demonstrate the computation of both WEI and xWEI. We find that the choice of the index can lead to considerable differences in the assessment of past events but that the most extreme events are ranked consistently, independently of the index. Even then, the xWEI can reveal cross-scale properties which would otherwise remain hidden. This also applies to the disastrous event from July 2021, which clearly outranks all other analyzed events with regard to both WEI and xWEI. While demonstrating the added value of xWEI, we also identify various methodological challenges along the required computational workflow: these include the parameter estimation for the extreme value distributions, the definition of maximum spatial extent and temporal duration, and the weighting of extremeness at different scales. These challenges, however, also represent opportunities to adjust the retrieval of WEI and xWEI to specific user requirements and application scenarios.}, language = {en} } @article{VaidyaSchmidtRakowskietal.2021, author = {Vaidya, Shrijana and Schmidt, Marten and Rakowski, Peter and Bonk, Norbert and Verch, Gernot and Augustin, J{\"u}rgen and Sommer, Michael and Hoffmann, Mathias}, title = {A novel robotic chamber system allowing to accurately and precisely determining spatio-temporal CO2 flux dynamics of heterogeneous croplands}, series = {Agricultural and forest meteorology}, volume = {296}, journal = {Agricultural and forest meteorology}, publisher = {Elsevier}, address = {Amsterdam}, issn = {0168-1923}, doi = {10.1016/j.agrformet.2020.108206}, pages = {9}, year = {2021}, abstract = {The precise and accurate assessment of carbon dioxide (CO2) exchange is crucial to identify terrestrial carbon (C) sources and sinks and for evaluating their role within the global C budget. The substantial uncertainty in disentangling the management and soil impact on measured CO2 fluxes are largely ignored especially in cropland. The reasons for this lies in the limitation of the widely used eddy covariance as well as manual and automatic chamber systems, which either account for short-term temporal variability or small-scale spatial heterogeneity, but barely both. To address this issue, we developed a novel robotic chamber system allowing for dozens of spatial measurement repetitions, thus enabling CO2 exchange measurements in a sufficient temporal and high small-scale spatial resolution. The system was tested from 08th July to 09th September 2019 at a heterogeneous field (100 m x 16 m), located within the hummocky ground moraine landscape of northeastern Germany (CarboZALF-D). The field is foreseen for a longer-term block trial manipulation experiment extending over three erosion induced soil types and was covered with spring barley. Measured fluxes of nighttime ecosystem respiration (R-eco) and daytime net ecosystem exchange (NEE) showed distinct temporal patterns influenced by crop phenology, weather conditions and management practices. Similarly, we found clear small-scale spatial differences in cumulated (gap-filled) R-eco, gross primary productivity (GPP) and NEE fluxes affected by the three distinct soil types. Additionally, spatial patterns induced by former management practices and characterized by differences in soil pH and nutrition status (P and K) were also revealed between plots within each of the three soil types, which allowed compensating for prior to the foreseen block trial manipulation experiment. The results underline the great potential of the novel robotic chamber system, which not only detects short-term temporal CO2 flux dynamics but also reflects the impact of small-scale spatial heterogeneity.}, language = {en} }