TY  - JOUR
A1  - Bürger, Gerd
A1  - Pfister, Angela
A1  - Bronstert, Axel
T1  - Zunehmende Starkregenintensitäten als Folge der Klimaerwärmung
T1  - Increasing intensity of heavy rainfall caused by global warming
BT  - Datenanalyse und Zukunftsprojektion
BT  - data analysis and future projections
JF  - Hydrologie und Wasserbewirtschaftung : HyWa = Hydrology and water resources management, Germany / Hrsg.: Fachverwaltungen des Bundes und der Länder
N2  - Extreme rainfall events of short duration in the range of hours and below are increasingly coming into focus due to the resulting damage from flash floods and also due to their possible intensification by anthropogenic climate change. The current study investigates possible trends in heavy rainfall intensities for stations from Swiss and Austrian alpine regions as well as for the Emscher-Lippe area in North Rhine-Westphalia on the basis of partly very long (> 50 years) and temporally highly resolved time series (<= 15 minutes). It becomes clear that there is an increase in extreme rainfall intensities, which can be well explained by the warming of the regional climate: the analyses of long-term trends in exceedance counts and return levels show considerable uncertainties, but are in the order of 30 % increase per century. In addition, based on an "average" climate simulation for the 21st century, this paper describes a projection for extreme precipitation intensities at very high temporal resolution for a number of stations in the Emscher-Lippe region. A coupled spatial and temporal "downscaling" is applied, the key innovation of which is the consideration of the dependence of local rainfall intensity on air temperature. This procedure involves two steps: First, large-scale climate fields at daily resolution are statistically linked by regression to station temperature and precipitation values (spatial downscaling). In the second step, these station values are disaggregated to a temporal resolution of 10 minutes using a so-called multiplicative stochastic cascade model (MC) (temporal downscaling). The novel, temperature-sensitive variant additionally considers air temperature as an explanatory variable for precipitation intensities. Thus, the higher atmospheric moisture content expected with warming, which results from the Clausius-Clapeyron (CC) relationship, is included in the temporal downscaling. <br /> For the statistical evaluation of the extreme short-term precipitation, the upper quantiles (99.9 %), exceedance counts (P > 5mm), and 3-yr return levels of the <= 15-min duration step has been used. Only by adding temperature is the observed temperature observed of the extreme quantiles ("CC scaling") well reproduced. When comparing observed data and present-day simulations of the model cascade, the temperature-sensitive procedure shows consistent results. Compared to trends in recent decades, similar or even larger increases in extreme intensities are projected for the future. This is remarkable in that these appear to be driven primarily by local temperature, as the projected trends in daily precipitation values are negligible for this region.
N2  - Extreme Regenereignisse von kurzer Dauer im Bereich von Stunden und darunter rücken aufgrund der dadurch bedingten Schäden durch Sturzfluten und auch wegen ihrer möglichen Intensivierungen durch den anthropogenen Klimawandel immer stärker in den Fokus. Die vorliegende Studie untersucht auf Basis von teilweise sehr langen (> 50 Jahre) und zeitlich hochaufgelösten Zeitreihen (≤ 15 Minuten) mögliche Trends in Starkregenintensitäten für Stationen aus schweizerischen und österreichischen Alpenregionen sowie für das Emscher-Lippe-Gebiet in Nordrhein-Westfalen. Es wird deutlich, dass es eine Zunahme der extremen Niederschlagsintensitäten gibt, welche gut durch die Erwärmung des regionalen Klimas erklärt werden kann: Die Analysen langfristiger Trends der Überschreitungssummen und Wiederkehrniveaus zeigen zwar erhebliche Unsicherheiten, lassen jedoch eine Zunahme in einer Größenordnung von 30 % pro Jahrhundert erkennen. Zudem wird in diesem Beitrag, basierend auf einer "mittleren" Klimasimulation für das 21. Jahrhundert, für ausgewählte Stationen der Emscher-Lippe-Region eine Projektion für extreme Niederschlagsintensitäten in sehr hoher zeitlicher Auflösung beschrieben. Dabei wird ein gekoppeltes räumliches und zeitliches "Downscaling" angewendet, dessen entscheidende Neuerung die Berücksichtigung der Abhängigkeit der lokalen Regenintensität von der Lufttemperatur ist. Dieses Verfahren beinhaltet zwei Schritte: Zuerst werden großräumige Klimafelder in täglicher Auflösung durch Regression mit den Temperatur- und Niederschlagswerten der Stationen statistisch verbunden (räumliches Downscaling). Im zweiten Schritt werden dann diese Stationswerte mithilfe eines sogenannten multiplikativen stochastischen Kaskadenmodells (MC) auf eine zeitliche Auflösung von 10 Minuten disaggregiert (zeitliches Downscaling). Die neuartige, temperatursensitive Variante berücksichtigt zusätzlich die Lufttemperatur als erklärende Variable für die Niederschlagsintensitäten. Dadurch wird der mit einer Erwärmung zu erwartende höhere atmosphärische Feuchtegehalt, welcher sich aus der Clausius-Clapeyron-Beziehung (CC) ergibt, mit in das zeitliche Downscaling einbezogen.
Für die statistische Auswertung der extremen kurzfristigen Niederschläge wurden die oberen Quantile (99,9 %), Überschreitungssummen (ÜS, P > 5 mm) und 3-jährliche Wiederkehrniveaus (WN) einer Dauerstufe von ≤ 15-Minuten betrachtet. Diese Auswahl erlaubt die gleichzeitige Analyse sowohl von Extremwertstatistiken als auch von deren langfristigen Trends; leichte Abweichungen von dieser Wahl beeinflussen die Hauptergebnisse nur unwesentlich. Nur durch die Hinzunahme der Temperatur wird die beobachtete Temperaturabhängigkeit der extremen Quantile (CC-Scaling) gut wiedergegeben. Bei Vergleich von Beobachtungsdaten und Gegenwartssimulationen der Modellkaskade zeigt das temperatursensitive Verfahren konsistente Ergebnisse. Im Vergleich zu den Entwicklungen der letzten Jahrzehnte werden für die Zukunft ähnliche oder sogar noch stärkere Anstiege der extremen Niederschlagsintensitäten projiziert. Dies ist insofern bemerkenswert, als diese anscheinend hauptsächlich durch die örtliche Temperatur bestimmt werden, denn die projizierten Trends der Niederschlags-Tageswerte sind für diese Region vernachlässigbar.
KW  - heavy rainfall
KW  - short duration
KW  - global warming
KW  - Clausius-Clapeyron
KW  - equation
KW  - precipitation intensity
KW  - multiplicative cascade model
KW  - Strakregen
KW  - kurzfristige Dauerstufe
KW  - Klimawandel
KW  - Clausius-Clapeyron-Gleichung
KW  - Niederschlagsintensitäten
KW  - Multiplikatives Kaskadenmodel
Y1  - 2021
U6  - https://doi.org/10.5675/HyWa_2021.6_1
SN  - 1439-1783
SN  - 2749-859X
VL  - 65
IS  - 6
SP  - 262
EP  - 271
PB  - Bundesanst. für Gewässerkunde
CY  - Koblenz
ER  - 
TY  - JOUR
A1  - Vormoor, Klaus Josef
A1  - Rossler, Ole
A1  - Bürger, Gerd
A1  - Bronstert, Axel
A1  - Weingartner, Rolf
T1  - When timing matters-considering changing temporal structures in runoff response surfaces
JF  - Climatic change : an interdisciplinary, intern. journal devoted to the description, causes and implications of climatic change
N2  - Scenario-neutral response surfaces illustrate the sensitivity of a simulated natural system, represented by a specific impact variable, to systematic perturbations of climatic parameters. This type of approach has recently been developed as an alternative to top-down approaches for the assessment of climate change impacts. A major limitation of this approach is the underrepresentation of changes in the temporal structure of the climate input data (i.e., the seasonal and day-to-day variability) since this is not altered by the perturbation. This paper presents a framework that aims to examine this limitation by perturbing both observed and projected climate data time series for a future period, which both serve as input into a hydrological model (the HBV model). The resulting multiple response surfaces are compared at a common domain, the standardized runoff response surface (SRRS). We apply this approach in a case study catchment in Norway to (i) analyze possible changes in mean and extreme runoff and (ii) quantify the influence of changes in the temporal structure represented by 17 different climate input sets using linear mixed-effect models. Results suggest that climate change induced increases in mean and peak flow runoff and only small changes in low flow. They further suggest that the effect of the different temporal structures of the climate input data considerably affects low flows and floods (at least 21% influence), while it is negligible for mean runoff.
Y1  - 2017
U6  - https://doi.org/10.1007/s10584-017-1940-1
SN  - 0165-0009
SN  - 1573-1480
VL  - 142
SP  - 213
EP  - 226
PB  - Springer
CY  - Dordrecht
ER  - 
TY  - JOUR
A1  - Francke, Till
A1  - Baroni, Gabriele
A1  - Brosinsky, Arlena
A1  - Foerster, Saskia
A1  - Lopez-Tarazon, José Andrés
A1  - Sommerer, Erik
A1  - Bronstert, Axel
T1  - What Did Really Improve Our Mesoscale Hydrological Model?
BT  - a Multidimensional Analysis Based on Real Observations
JF  - Water resources research
N2  - Modelers can improve a model by addressing the causes for the model errors (data errors and structural errors). This leads to implementing model enhancements (MEs), for example, meteorological data based on more monitoring stations, improved calibration data, and/or modifications in process formulations. However, deciding on which MEs to implement remains a matter of expert knowledge. After implementing multiple MEs, any improvement in model performance is not easily attributed, especially when considering different objectives or aspects of this improvement (e.g., better dynamics vs. reduced bias). We present an approach for comparing the effect of multiple MEs based on real observations and considering multiple objectives (MMEMO). A stepwise selection approach and structured plots help to address the multidimensionality of the problem. Tailored analyses allow a differentiated view on the effect of MEs and their interactions. MMEMO is applied to a case study employing the mesoscale hydro-sedimentological model WASA-SED for the Mediterranean-mountainous Isabena catchment, northeast Spain. The investigated seven MEs show diverse effects: some MEs (e.g., rainfall data) cause improvements for most objectives, while other MEs (e.g., land use data) only affect a few objectives or even decrease model performance. Interaction of MEs was observed for roughly half of the MEs, confirming the need to address them in the analysis. Calibration and increasing the temporal resolution showed by far stronger impact than any of the other MEs. The proposed framework can be adopted in other studies to analyze the effect of MEs and, thus, facilitate the identification and implementation of the most promising MEs for comparable cases.
KW  - modeling
KW  - sensitivity analyses
KW  - model enhancement
KW  - sediment
Y1  - 2018
U6  - https://doi.org/10.1029/2018WR022813
SN  - 0043-1397
SN  - 1944-7973
VL  - 54
IS  - 11
SP  - 8594
EP  - 8612
PB  - American Geophysical Union
CY  - Washington
ER  - 
TY  - JOUR
A1  - Bronstert, Axel
A1  - Krol, Marten S.
A1  - Jaeger, Annekathrin
T1  - WAVES : water availability, vulnerability of ecosystems and society in northeast brazil ; an overview of the interdisciplinary project and integrated modelling
Y1  - 2000
ER  - 
TY  - JOUR
A1  - Güntner, Andreas
A1  - Bronstert, Axel
T1  - WAVES - Water availability, vulnerability of ecosystems and society in the northeast of Brazil : sub-project large-scale hydrological modelling
Y1  - 2001
ER  - 
TY  - JOUR
A1  - Francke, Till
A1  - Förster, Saskia
A1  - Brosinsky, Arlena
A1  - Sommerer, Erik
A1  - Lopez-Tarazonl, Jose Andres
A1  - Güntner, Andreas
A1  - Batalla, Ramon J.
A1  - Bronstert, Axel
T1  - Water and sediment fluxes in Mediterranean mountainous regions
BT  - comprehensive dataset for hydro-sedimentological analyses and modelling in a mesoscale catchment (River Isabena, NE Spain)
JF  - Earth System Science Data
N2  - A comprehensive hydro-sedimentological dataset for the Isabena catchment, northeastern (NE) Spain, for the period 2010-2018 is presented to analyse water and sediment fluxes in a Mediterranean mesoscale catchment. The dataset includes rainfall data from 12 rain gauges distributed within the study area complemented by meteorological data of 12 official meteo-stations. It comprises discharge data derived from water stage measurements as well as suspended sediment concentrations (SSCs) at six gauging stations of the River Isabena and its sub-catchments. Soil spectroscopic data from 351 suspended sediment samples and 152 soil samples were collected to characterize sediment source regions and sediment properties via fingerprinting analyses. The Isabena catchment (445 km(2)) is located in the southern central Pyrenees ranging from 450 m to 2720 m a.s.l.; together with a pronounced topography, this leads to distinct temperature and precipitation gradients. The River Isabena shows marked discharge variations and high sediment yields causing severe siltation problems in the downstream Barasona Reservoir. The main sediment source is badland areas located on Eocene marls that are well connected to the river network. The dataset features a comprehensive set of variables in a high spatial and temporal resolution suitable for the advanced process understanding of water and sediment fluxes, their origin and connectivity and sediment budgeting and for the evaluation and further development of hydro-sedimentological models in Mediterranean mesoscale mountainous catchments.
Y1  - 2018
U6  - https://doi.org/10.5194/essd-10-1063-2018
SN  - 1866-3508
SN  - 1866-3516
VL  - 10
IS  - 2
SP  - 1063
EP  - 1075
PB  - Copernicus
CY  - Göttingen
ER  - 
TY  - GEN
A1  - Francke, Till
A1  - Förster, Saskia
A1  - Brosinsky, Arlena
A1  - Sommerer, Erik
A1  - Lopez-Tarazon, Jose Andres
A1  - Güntner, Andreas
A1  - Batalla  Villanueva, Ramon J.
A1  - Bronstert, Axel
T1  - Water and sediment fluxes in Mediterranean mountainous regions
BT  - comprehensive dataset for hydro-sedimentological analyses and modelling in a mesoscale catchment (River Isábena, NE Spain)
T2  - Postprints der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe
N2  - A comprehensive hydro-sedimentological dataset for the Isábena catchment, northeastern (NE) Spain, for the period 2010–2018 is presented to analyse water and sediment fluxes in a Mediterranean mesoscale catchment. The dataset includes rainfall data from 12 rain gauges distributed within the study area complemented by meteorological data of 12 official meteo-stations. It comprises discharge data derived from water stage measurements as well as suspended sediment concentrations (SSCs) at six gauging stations of the River Isábena and its sub-catchments. Soil spectroscopic data from 351 suspended sediment samples and 152 soil samples were collected to characterize sediment source regions and sediment properties via fingerprinting analyses. The Isábena catchment (445 km 2 ) is located in the southern central Pyrenees ranging from 450 m to 2720 m a.s.l.; together with a pronounced topography, this leads to distinct temperature and precipitation gradients. The River Isábena shows marked discharge variations and high sediment yields causing severe siltation problems in the downstream Barasona Reservoir. The main sediment source is badland areas located on Eocene marls that are well connected to the river network. The dataset features a comprehensive set of variables in a high spatial and temporal resolution suitable for the advanced process understanding of water and sediment fluxes, their origin and connectivity and sediment budgeting and for the evaluation and further development of hydro-sedimentological models in
Mediterranean mesoscale mountainous catchments.
T3  - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 547 
KW  - source siscrimination
KW  - transport
KW  - pyrenees
KW  - connectivity
KW  - sischarge
KW  - runoff
KW  - yield
Y1  - 2019
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-419150
SN  - 1866-8372
IS  - 547
ER  - 
TY  - JOUR
A1  - Krause, Stefan
A1  - Bronstert, Axel
T1  - Wasserhaushaltssimulationen unter Einbeziehung von Grundwasser - Oberflächenwasser - Kopplung zur Optimierung szenarienbasierter Handlungsoptionen für ein nachhaltiges Flussgebietsmanagement an der Unteren Havel
Y1  - 2004
SN  - 3-89958-072-9
ER  - 
TY  - JOUR
A1  - Krause, Stefan
A1  - Bauer, Andreas
A1  - Morgner, Markus
A1  - Bronstert, Axel
T1  - Wasserhaushaltsmodellierung als Beitrag zur Erstellung eines nachhaltigen Flusseinzugsgebietsmanagements an der Unteren Havel
Y1  - 2004
SN  - 3-937758-18-6
ER  - 
TY  - BOOK
A1  - Bronstert, Axel
A1  - Thieken, Annegret
A1  - Merz, Bruno
A1  - Rode, Michael
A1  - Menzel, Lucas
T1  - Wasser- und Stofftransport in heterogenen Einzugsgebieten : Beiträge zum Tag der Hydrologie 2004, 22./ 23. März 2004 in Potsdam ; Bd. 2 Poster
Y1  - 2004
SN  - 3-937758-18-6
PB  - ATV-DVWK
CY  - Hennef
ER  - 
TY  - BOOK
A1  - Bronstert, Axel
A1  - Thieken, Annegret
A1  - Merz, Bruno
A1  - Rode, Michael
A1  - Menzel, Lucas
T1  - Wasser- und Stofftransport in heterogenen Einzugsgebieten : Beiträge zum Tag der Hydrologie 2004, 22./ 23. März 2004 in Potsdam ; Bd. 1 Vorträge
Y1  - 2004
SN  - 3-937758-18-6
VL  - 5
PB  - ATV-DVWK
CY  - Hennef (Sieg)
ER  - 
TY  - JOUR
A1  - Bronstert, Axel
A1  - Bürger, Gerhard
A1  - Pfister, Angela
T1  - Vorhersage und Projektion von Sturzfluten - Vorwort
JF  - Hydrologie und Wasserbewirtschaftung : HyWa = Hydrology and water resources management, Germany / Hrsg.: Fachverwaltungen des Bundes und der Länder
T2  - Forecasting and projection of flash flood
Y1  - 2021
SN  - 1439-1783
SN  - 2749-859X
VL  - 65
IS  - 6
SP  - 260
EP  - 261
PB  - Bundesanst. für Gewässerkunde, BfG
CY  - Koblenz
ER  - 
TY  - JOUR
A1  - Bronstert, Axel
A1  - Engel, H.
T1  - Veränderung der Abflüsse
JF  - Warnsignal Klima - genug Wasser für alle? : wissenschaftliche Fakten
Y1  - 2005
SN  - 978-3-9809668-0-1
SP  - 175
EP  - 181
PB  - Wissenschaftliche Auswertungen
CY  - Hamburg
ER  - 
TY  - GEN
A1  - Kneis, David
A1  - Abon, Catherine Cristobal
A1  - Bronstert, Axel
A1  - Heistermann, Maik
T1  - Verification of short-term runoff forecasts for a small Philippine basin (Marikina)
T2  - Hydrological sciences journal = Journal des sciences hydrologiques
N2  - Storm runoff from the Marikina River Basin frequently causes flood events in the Philippine capital region Metro Manila. This paper presents and evaluates a system to predict short-term runoff from the upper part of that basin (380km(2)). It was designed as a possible component of an operational warning system yet to be installed. For the purpose of forecast verification, hindcasts of streamflow were generated for a period of 15 months with a time-continuous, conceptual hydrological model. The latter was fed with real-time observations of rainfall. Both ground observations and weather radar data were tested as rainfall forcings. The radar-based precipitation estimates clearly outperformed the raingauge-based estimates in the hydrological verification. Nevertheless, the quality of the deterministic short-term runoff forecasts was found to be limited. For the radar-based predictions, the reduction of variance for lead times of 1, 2 and 3hours was 0.61, 0.62 and 0.54, respectively, with reference to a no-forecast scenario, i.e. persistence. The probability of detection for major increases in streamflow was typically less than 0.5. Given the significance of flood events in the Marikina Basin, more effort needs to be put into the reduction of forecast errors and the quantification of remaining uncertainties.
Y1  - 2016
U6  - https://doi.org/10.1080/02626667.2016.1183773
SN  - 0262-6667
SN  - 2150-3435
VL  - 62
SP  - 205
EP  - 216
PB  - Oxford Univ. Press
CY  - Oxford
ER  - 
TY  - JOUR
A1  - Heistermann, Maik
A1  - Crisologo, Irene
A1  - Abon, Catherine Cristobal
A1  - Racoma, B. A.
A1  - Jacobi, S.
A1  - Servando, N. T.
A1  - David, C. P. C.
A1  - Bronstert, Axel
T1  - Using the new Philippine radar network to reconstruct the Habagat of August 2012 monsoon event around Metropolitan Manila
JF  - Natural hazards and earth system sciences
N2  - From 6 to 9 August 2012, intense rainfall hit the northern Philippines, causing massive floods in Metropolitan Manila and nearby regions. Local rain gauges recorded almost 1000mm within this period. However, the recently installed Philippine network of weather radars suggests that Metropolitan Manila might have escaped a potentially bigger flood just by a whisker, since the centre of mass of accumulated rainfall was located over Manila Bay. A shift of this centre by no more than 20 km could have resulted in a flood disaster far worse than what occurred during Typhoon Ketsana in September 2009.
Y1  - 2013
U6  - https://doi.org/10.5194/nhess-13-653-2013
SN  - 1561-8633
VL  - 13
IS  - 3
SP  - 653
EP  - 657
PB  - Copernicus
CY  - Göttingen
ER  - 
TY  - GEN
A1  - Blume, Theresa
A1  - Zehe, Erwin
A1  - Bronstert, Axel
T1  - Use of soil moisture dynamics and patterns at different spatio-temporal scales for the investigation of subsurface flow processes
N2  - Spatial patterns as well as temporal dynamics of soil moisture have a major influence on runoff generation. The investigation of these dynamics and patterns can thus yield valuable information on hydrological processes, especially in data scarce or previously ungauged catchments. The combination of spatially scarce but temporally high resolution soil moisture profiles with episodic and thus temporally scarce moisture profiles at additional locations provides information on spatial as well as temporal patterns of soil moisture at the hillslope transect scale. This approach is better suited to difficult terrain (dense forest, steep slopes) than geophysical techniques and at the same time less cost-intensive than a high resolution grid of continuously measuring sensors. Rainfall simulation experiments with dye tracers while continuously monitoring soil moisture response allows for visualization of flow processes in the unsaturated zone at these locations. Data was analyzed at different spacio-temporal scales using various graphical methods, such as space-time colour maps (for the event and plot scale) and binary indicator maps (for the long-term and hillslope scale). Annual dynamics of soil moisture and decimeterscale variability were also investigated. The proposed approach proved to be successful in the investigation of flow processes in the unsaturated zone and showed the importance of preferential flow in the Malalcahuello Catchment, a datascarce catchment in the Andes of Southern Chile. Fast response times of stream flow indicate that preferential flow observed at the plot scale might also be of importance at the hillslope or catchment scale. Flow patterns were highly variable in space but persistent in time. The most likely explanation for preferential flow in this catchment is a combination of hydrophobicity, small scale heterogeneity in rainfall due to redistribution in the canopy and strong gradients in unsaturated conductivities leading to self-reinforcing flow paths.
T3  - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - paper 125 
KW  - Repellent sandy soil
KW  - Poorly gauged catchment
KW  - Volcanic ash soils
KW  - Water repellency
KW  - Preferential flow
Y1  - 2009
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-44924
ER  - 
TY  - JOUR
A1  - Bronstert, Axel
A1  - Bardossy, Andras
T1  - Uncertainty of runoff modelling at the hillslope scale due to temporal variations of rainfall intensity
Y1  - 2003
ER  - 
TY  - CHAP
A1  - Lück, Erika
A1  - Balderjahn, Ingo
A1  - Kamm, Birgit
A1  - Greil, Holle
A1  - Wallschläger, Hans-Dieter
A1  - Jessel, Beate
A1  - Böckmann, Christine
A1  - Oberhänsli, Roland
A1  - Soyez, Konrad
A1  - Schmeer, Ernst
A1  - Blumenstein, Oswald
A1  - Berndt, Klaus-Peter
A1  - Edeling, Thomas
A1  - Friedrich, Sabine
A1  - Kaden, Klaus
A1  - Scheller, Frieder W.
A1  - Petersen, Hans-Georg
A1  - Asche, Hartmut
A1  - Bronstert, Axel
A1  - Giest, Hartmut
A1  - Gaedke, Ursula
A1  - Löhmannsröben, Hans-Gerd
A1  - Jeltsch, Florian
A1  - Jänkel, Ralph
A1  - Gzik, Axel
A1  - Bork, Hans-Rudolf
A1  - Bork, Hans-Rudolf
T1  - Umweltforschung für das Land Brandenburg : Arbeitsgruppen und Professuren
Y1  - 2000
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-3797
ER  - 
TY  - JOUR
A1  - Tittel, Jörg
A1  - Bork, Rudolf
A1  - Röpke, Björn
A1  - Geldmacher, Karl
A1  - Schnur, Tilo
A1  - Faust, Berno
A1  - Schaphoff, Sibyll
A1  - Dalchow, Claus
A1  - Woithe, Franka
A1  - Bronstert, Axel
A1  - Jeltsch, Florian
A1  - Jessel, Beate
A1  - Zschalich, Andrea
A1  - Rößling, Holger
A1  - Spindler, Joris
A1  - Gaedke, Ursula
A1  - Tielbörger, Katja
A1  - Kadmon, R.
A1  - Müller, J.
A1  - Bissinger, Vera
A1  - Weithoff, Guntram
A1  - Wallschläger, Hans-Dieter
A1  - Wiegleb, Gerhard
T1  - Umweltforschung für das Land Brandenburg
BT  - Projekt Ökologie und Naturschutz / Landschaftsplanung / Landschaftsentwicklung
JF  - Brandenburgische Umwelt-Berichte : BUB ; Schriftenreihe der Mathematisch-Naturwissenschaftlichen Fakultät der Universität Potsdam
N2  - BISSINGER, V.; TITTEL, J.: Process rates and growth limiting factors of planktonic algae (Chlamydomonas sp.) from extremely acidic (pH 2,5 - 3) mining lakes in Germany ; BORK, H.-R. et al.: Erodierte Autos und Brunnen in Oregon, USA ; BRONSTERT, A. et al.: Bewirtschaftunsmöglichkeiten im Einzugsgebiet der Havel ; JELTSCH, F. et al.: Beweidung als Degradationsfaktor in ariden und semiariden Weidesystemen ; JELTSCH, F. et al.: Entstehung und Bedeutung räumlicher Vegetationsstrukturen in Trockensavannen: Baum-Graskoexistenz und Artenvielfalt ; JESSEL, B. et al.: Bodenbewertung für Planungs- und Zulassungsverfahren in Brandenburg ; JESSEL, B.; ZSCHALICH, A.: Erarbeitung von Ausgleichs- und Ersatzmaßnahmen für die Wert- und Funktionselemente des Landschaftsbildes ; RÖßLING, H. et al.: Umsetzung von Ausgleichs- und Ersatzmaßnahmen beim Ausbau der Bundesautobahn A 9 ; SPINDLER, J.; GAEDKE, U.: Estimating production in plankton food webs from biomass size spectra and allometric relationships ; TIELBÖRGER, K. et al.: Sukzessionsprozesse in einem Sanddünengebiet nach Ausschluß von Beweidung ; TIELBÖRGER, K. et al.: Populationsdynamische Funktionen von Ausbreitung und Dormanz ; TIELBÖRGER, K. et al.: Raum-zeitliche Populationsdynamik von einjährigen Wüstenpflanzen ; TITTEL, J. et al.: Ressourcennutzung und -weitergabe im planktischen Nahrungsnetz eines extrem sauren (pH 2,7) Tagebausees ; WALLSCHLÄGER, D.; WIEGLEB, G.: Offenland-Management auf ehemaligen und in Nutzung befindlichen Truppenübungsplätzen im pleistozänen Flachland Nordostdeutschlands: Naturschutzfachliche Grundlagen und praktische Anwendungen ; WEITHOFF, G.; GAEDKE, U.: Planktische Räuber-Beute-Systeme: Experimentelle Untersuchung von ökologischen Synchronisationen
Y1  - 2000
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-3828
SN  - 1434-2375
SN  - 1611-9339
VL  - 8
SP  - 80
EP  - 134
ER  - 
TY  - JOUR
A1  - Blumenstein, Oswald
A1  - Bronstert, Axel
A1  - Günter, A.
A1  - Katzenmeier, D.
A1  - Friedrich, Sabine
A1  - Geldmacher, Karl
A1  - Bork, Rudolf
A1  - Röpke, Björn
A1  - Schaphoff, Sibyll
A1  - Schnur, Tilo
A1  - Woithe, Franka
A1  - Dalchow, Claus
A1  - Faust, Berno
A1  - Itzerott, Sibylle
A1  - Kaden, Klaus
A1  - Knösche, Rüdiger
T1  - Umweltforschung für das Land Brandenburg
BT  - Projekt Schutzgüter Wasser, Boden, Luft
JF  - Brandenburgische Umwelt-Berichte : BUB ; Schriftenreihe der Mathematisch-Naturwissenschaftlichen Fakultät der Universität Potsdam
N2  - BLUMENSTEIN, O.: Investigation of Environmental Quality and Social Structures in a Mining Area in the North West Province of South Africa ; BRONSTERT, A.; GÜNTNER, A.: A large-scale hydrological model for the semi-arid environment of north-eastern Brazil ; BRONSTERT, A. et al.: Hochwasserproblematik und der Zusammenhang mit Landnutzungs- und Klimaänderungen ; FRIEDRICH, S.: Vergleichende Untersuchungen zur Wasserqualität des anfallenden Regenwassers an den 14 Regenwassereinläufen der Stadt Potsdam ; GELDMACHER, K. et al.: Bodenzerstörung im Palouse, Washington, USA ; ITZEROTT, S.; KADEN, K.: Modellierung der flächenhaften Verdunstung im Gebiet der Unteren Havel ; KNÖSCHE, R.: Das remobilisierbare Nährstoffpotential in Augewässersedimenten einer Tieflandflußaue
Y1  - 2000
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-3845
SN  - 1434-2375
SN  - 1611-9339
VL  - 8
SP  - 136
EP  - 173
ER  - 
TY  - JOUR
A1  - Seleem, Omar
A1  - Ayzel, Georgy
A1  - Bronstert, Axel
A1  - Heistermann, Maik
T1  - Transferability of data-driven models to predict urban pluvial flood water depth in Berlin, Germany
JF  - Natural Hazards and Earth System Sciences
N2  - Data-driven models have been recently suggested to surrogate computationally expensive hydrodynamic models to map flood hazards. However, most studies focused on developing models for the same area or the same precipitation event. It is thus not obvious how transferable the models are in space. This study evaluates the performance of a convolutional neural network (CNN) based on the U-Net architecture and the random forest (RF) algorithm to predict flood water depth, the models' transferability in space and performance improvement using transfer learning techniques. We used three study areas in Berlin to train, validate and test the models. The results showed that (1) the RF models outperformed the CNN models for predictions within the training domain, presumable at the cost of overfitting; (2) the CNN models had significantly higher potential than the RF models to generalize beyond the training domain; and (3) the CNN models could better benefit from transfer learning technique to boost their performance outside training domains than RF models.
Y1  - 2023
U6  - https://doi.org/10.5194/nhess-23-809-2023
SN  - 1684-9981
SN  - 1561-8633
VL  - 23
IS  - 2
SP  - 809
EP  - 822
PB  - Copernicus
CY  - Göttingen
ER  - 
TY  - GEN
A1  - Seleem, Omar
A1  - Ayzel, Georgy
A1  - Bronstert, Axel
A1  - Heistermann, Maik
T1  - Transferability of data-driven models to predict urban pluvial flood water depth in Berlin, Germany
T2  - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe
N2  - Data-driven models have been recently suggested to surrogate computationally expensive hydrodynamic models to map flood hazards. However, most studies focused on developing models for the same area or the same precipitation event. It is thus not obvious how transferable the models are in space. This study evaluates the performance of a convolutional neural network (CNN) based on the U-Net architecture and the random forest (RF) algorithm to predict flood water depth, the models' transferability in space and performance improvement using transfer learning techniques. We used three study areas in Berlin to train, validate and test the models. The results showed that (1) the RF models outperformed the CNN models for predictions within the training domain, presumable at the cost of overfitting; (2) the CNN models had significantly higher potential than the RF models to generalize beyond the training domain; and (3) the CNN models could better benefit from transfer learning technique to boost their performance outside training domains than RF models.
T3  - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 1323 
Y1  - 2023
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-589168
SN  - 1866-8372
IS  - 1323
SP  - 809
EP  - 822
ER  - 
TY  - JOUR
A1  - Seleem, Omar
A1  - Ayzel, Georgy
A1  - Costa Tomaz de Souza, Arthur
A1  - Bronstert, Axel
A1  - Heistermann, Maik
T1  - Towards urban flood susceptibility mapping using data-driven models in Berlin, Germany
JF  - Geomatics, natural hazards and risk
N2  - Identifying urban pluvial flood-prone areas is necessary but the application of two-dimensional hydrodynamic models is limited to small areas. Data-driven models have been showing their ability to map flood susceptibility but their application in urban pluvial flooding is still rare. A flood inventory (4333 flooded locations) and 11 factors which potentially indicate an increased hazard for pluvial flooding were used to implement convolutional neural network (CNN), artificial neural network (ANN), random forest (RF) and support vector machine (SVM) to: (1) Map flood susceptibility in Berlin at 30, 10, 5, and 2 m spatial resolutions. (2) Evaluate the trained models' transferability in space. (3) Estimate the most useful factors for flood susceptibility mapping. The models' performance was validated using the Kappa, and the area under the receiver operating characteristic curve (AUC). The results indicated that all models perform very well (minimum AUC = 0.87 for the testing dataset). The RF models outperformed all other models at all spatial resolutions and the RF model at 2 m spatial resolution was superior for the present flood inventory and predictor variables. The majority of the models had a moderate performance for predictions outside the training area based on Kappa evaluation (minimum AUC = 0.8). Aspect and altitude were the most influencing factors on the image-based and point-based models respectively. Data-driven models can be a reliable tool for urban pluvial flood susceptibility mapping wherever a reliable flood inventory is available.
KW  - Urban pluvial flood susceptibility
KW  - convolutional neural network
KW  - deep
KW  - learning
KW  - random forest
KW  - support vector machine
KW  - spatial resolution;
KW  - flood predictors
Y1  - 2022
U6  - https://doi.org/10.1080/19475705.2022.2097131
SN  - 1947-5705
SN  - 1947-5713
VL  - 13
IS  - 1
SP  - 1640
EP  - 1662
PB  - Taylor & Francis
CY  - London
ER  - 
TY  - GEN
A1  - Seleem, Omar
A1  - Ayzel, Georgy
A1  - Costa Tomaz de Souza, Arthur
A1  - Bronstert, Axel
A1  - Heistermann, Maik
T1  - Towards urban flood susceptibility mapping using data-driven models in Berlin, Germany
T2  - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe
N2  - Identifying urban pluvial flood-prone areas is necessary but the application of two-dimensional hydrodynamic models is limited to small areas. Data-driven models have been showing their ability to map flood susceptibility but their application in urban pluvial flooding is still rare. A flood inventory (4333 flooded locations) and 11 factors which potentially indicate an increased hazard for pluvial flooding were used to implement convolutional neural network (CNN), artificial neural network (ANN), random forest (RF) and support vector machine (SVM) to: (1) Map flood susceptibility in Berlin at 30, 10, 5, and 2 m spatial resolutions. (2) Evaluate the trained models' transferability in space. (3) Estimate the most useful factors for flood susceptibility mapping. The models' performance was validated using the Kappa, and the area under the receiver operating characteristic curve (AUC). The results indicated that all models perform very well (minimum AUC = 0.87 for the testing dataset). The RF models outperformed all other models at all spatial resolutions and the RF model at 2 m spatial resolution was superior for the present flood inventory and predictor variables. The majority of the models had a moderate performance for predictions outside the training area based on Kappa evaluation (minimum AUC = 0.8). Aspect and altitude were the most influencing factors on the image-based and point-based models respectively. Data-driven models can be a reliable tool for urban pluvial flood susceptibility mapping wherever a reliable flood inventory is available.
T3  - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 1297 
KW  - Urban pluvial flood susceptibility
KW  - convolutional neural network
KW  - deep learning
KW  - random forest
KW  - support vector machine
KW  - spatial resolution
KW  - flood predictors
Y1  - 2023
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-576806
SN  - 1866-8372
IS  - 1297
SP  - 1640
EP  - 1662
ER  - 
TY  - JOUR
A1  - Bürger, Gerd
A1  - Heistermann, Maik
A1  - Bronstert, Axel
T1  - Towards subdaily rainfall disaggregation via Clausius-Clapeyron
JF  - Journal of hydrometeorology
N2  - Two lines of research are combined in this study: first, the development of tools for the temporal disaggregation of precipitation, and second, some newer results on the exponential scaling of heavy short-term precipitation with temperature, roughly following the Clausius-Clapeyron (CC) relation. Having no extra temperature dependence, the traditional disaggregation schemes are shown to lack the crucial CC-type temperature dependence. The authors introduce a proof-of-concept adjustment of an existing disaggregation tool, the multiplicative cascade model of Olsson, and show that, in principal, it is possible to include temperature dependence in the disaggregation step, resulting in a fairly realistic temperature dependence of the CC type. They conclude by outlining the main calibration steps necessary to develop a full-fledged CC disaggregation scheme and discuss possible applications.
Y1  - 2014
U6  - https://doi.org/10.1175/JHM-D-13-0161.1
SN  - 1525-755X
SN  - 1525-7541
VL  - 15
IS  - 3
SP  - 1303
EP  - 1311
PB  - American Meteorological Soc.
CY  - Boston
ER  - 
TY  - JOUR
A1  - Fernandez-Palomino, Carlos Antonio
A1  - Hattermann, Fred
A1  - Krysanova, Valentina
A1  - Vega-Jacome, Fiorella
A1  - Bronstert, Axel
T1  - Towards a more consistent eco-hydrological modelling through multi-objective calibration
BT  - a case study in the Andean Vilcanota River basin, Perú
JF  - Hydrological sciences journal = Journal des sciences hydrologiques
N2  - Most hydrological studies rely on a model calibrated using discharge alone. However, judging the model reliability based on such calibration is problematic, as it does not guarantee the correct representation of internal hydrological processes. This study aims (a) to develop a comprehensive multi-objective calibration framework using remote sensing vegetation data and hydrological signatures (flow duration curve - FDC, and baseflow index) in addition to discharge, and (b) to apply this framework for calibration of the Soil and Water Assessment Tool (SWAT) in a typical Andean catchment. Overall, our calibration approach outperformed traditional discharge-based and FDC signature-based calibration strategies in terms of vegetation, streamflow, and flow partitioning simulation. New hydrological insights for the region are the following: baseflow is the main component of the streamflow sustaining the long dry-season flow, and pasture areas offer higher water yield and baseflow than other land-cover types. The proposed approach could be used in other data-scarce regions with complex topography.
KW  - Andes
KW  - eco-hydrology
KW  - SWAT
KW  - hydrological signatures
KW  - remote sensing
KW  - equifinality
Y1  - 2020
U6  - https://doi.org/10.1080/02626667.2020.1846740
SN  - 0262-6667
SN  - 2150-3435
VL  - 66
IS  - 1
SP  - 59
EP  - 74
PB  - Routledge, Taylor & Francis Group
CY  - Abingdon
ER  - 
TY  - GEN
A1  - Fernandez-Palomino, Carlos Antonio
A1  - Hattermann, Fred
A1  - Krysanova, Valentina
A1  - Vega-Jacome, Fiorella
A1  - Bronstert, Axel
T1  - Towards a more consistent eco-hydrological modelling through multi-objective calibration
BT  - a case study in the Andean Vilcanota River basin, Perú
T2  - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe
N2  - Most hydrological studies rely on a model calibrated using discharge alone. However, judging the model reliability based on such calibration is problematic, as it does not guarantee the correct representation of internal hydrological processes. This study aims (a) to develop a comprehensive multi-objective calibration framework using remote sensing vegetation data and hydrological signatures (flow duration curve - FDC, and baseflow index) in addition to discharge, and (b) to apply this framework for calibration of the Soil and Water Assessment Tool (SWAT) in a typical Andean catchment. Overall, our calibration approach outperformed traditional discharge-based and FDC signature-based calibration strategies in terms of vegetation, streamflow, and flow partitioning simulation. New hydrological insights for the region are the following: baseflow is the main component of the streamflow sustaining the long dry-season flow, and pasture areas offer higher water yield and baseflow than other land-cover types. The proposed approach could be used in other data-scarce regions with complex topography.
T3  - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 1377 
KW  - Andes
KW  - eco-hydrology
KW  - SWAT
KW  - hydrological signatures
KW  - remote sensing
KW  - equifinality
Y1  - 2020
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-568766
SN  - 1866-8372
IS  - 1
ER  - 
TY  - JOUR
A1  - Conradt, Tobias
A1  - Wechsung, F.
A1  - Bronstert, Axel
T1  - Three perceptions of the evapotranspiration landscape comparing spatial patterns from a distributed hydrological model, remotely sensed surface temperatures, and sub-basin water balances
JF  - Hydrology and earth system sciences : HESS
N2  - A problem encountered by many distributed hydrological modelling studies is high simulation errors at interior gauges when the model is only globally calibrated at the outlet. We simulated river runoff in the Elbe River basin in central Europe (148 268 km(2)) with the semi-distributed eco-hydrological model SWIM (Soil and Water Integrated Model). While global parameter optimisation led to Nash-Sutcliffe efficiencies of 0.9 at the main outlet gauge, comparisons with measured runoff series at interior points revealed large deviations. Therefore, we compared three different strategies for deriving sub-basin evapotranspiration: (1) modelled by SWIM without any spatial calibration, (2) derived from remotely sensed surface temperatures, and (3) calculated from long-term precipitation and discharge data. The results show certain consistencies between the modelled and the remote sensing based evapotranspiration rates, but there seems to be no correlation between remote sensing and water balance based estimations. Subsequent analyses for single sub-basins identify amongst others input weather data and systematic error amplification in inter-gauge discharge calculations as sources of uncertainty. The results encourage careful utilisation of different data sources for enhancements in distributed hydrological modelling.
Y1  - 2013
U6  - https://doi.org/10.5194/hess-17-2947-2013
SN  - 1027-5606
VL  - 17
IS  - 7
SP  - 2947
EP  - 2966
PB  - Copernicus
CY  - Göttingen
ER  - 
TY  - JOUR
A1  - Krol, Marten S.
A1  - Jaeger, Annekathrin
A1  - Bronstert, Axel
A1  - Krywkow, J.
T1  - The Semi-arid Integrated Model (SIM), a regional integrated model assessing water availability, vulnerability of ecosystems and society in NE-Brazil
Y1  - 2001
ER  - 
TY  - JOUR
A1  - Bronstert, Axel
T1  - The role of infiltration conditions for storm runoff generation at the hillslope and small catchment scale
Y1  - 2001
ER  - 
TY  - JOUR
A1  - Bronstert, Axel
T1  - The possible impacts of environmental changes on flood formation : relevant processes and model requirements
Y1  - 2000
ER  - 
TY  - GEN
A1  - Lopez Tarazon, José Andrés
A1  - Bronstert, Axel
A1  - Thieken, Annegret
A1  - Petrow, Theresia
T1  - The effects of global change on floods, fluvial geomorphology and related hazards in mountainous rivers
T2  - The science of the total environment : an international journal for scientific research into the environment and its relationship with man
Y1  - 2019
U6  - https://doi.org/10.1016/j.scitotenv.2019.03.026
SN  - 0048-9697
SN  - 1879-1026
VL  - 669
SP  - 7
EP  - 10
PB  - Elsevier
CY  - Amsterdam
ER  - 
TY  - JOUR
A1  - Mtilatila, Lucy Mphatso Ng'ombe
A1  - Bronstert, Axel
A1  - Vormoor, Klaus Josef
T1  - Temporal evaluation and projections of meteorological droughts in the Greater Lake Malawi Basin, Southeast Africa
JF  - Frontiers in water
N2  - The study examined the potential future changes of drought characteristics in the Greater Lake Malawi Basin in Southeast Africa. This region strongly depends on water resources to generate electricity and food. Future projections (considering both moderate and high emission scenarios) of temperature and precipitation from an ensemble of 16 bias-corrected climate model combinations were blended with a scenario-neutral response surface approach to analyses changes in: (i) the meteorological conditions, (ii) the meteorological water balance, and (iii) selected drought characteristics such as drought intensity, drought months, and drought events, which were derived from the Standardized Precipitation and Evapotranspiration Index. Changes were analyzed for a near-term (2021-2050) and far-term period (2071-2100) with reference to 1976-2005. The effect of bias-correction (i.e., empirical quantile mapping) on the ability of the climate model ensemble to reproduce observed drought characteristics as compared to raw climate projections was also investigated. Results suggest that the bias-correction improves the climate models in terms of reproducing temperature and precipitation statistics but not drought characteristics. Still, despite the differences in the internal structures and uncertainties that exist among the climate models, they all agree on an increase of meteorological droughts in the future in terms of higher drought intensity and longer events. Drought intensity is projected to increase between +25 and +50% during 2021-2050 and between +131 and +388% during 2071-2100. This translates into +3 to +5, and +7 to +8 more drought months per year during both periods, respectively. With longer lasting drought events, the number of drought events decreases. Projected droughts based on the high emission scenario are 1.7 times more severe than droughts based on the moderate scenario. That means that droughts in this region will likely become more severe in the coming decades. Despite the inherent high uncertainties of climate projections, the results provide a basis in planning and (water-)managing activities for climate change adaptation measures in Malawi. This is of particular relevance for water management issues referring hydro power generation and food production, both for rain-fed and irrigated agriculture.
KW  - meteorological drought
KW  - drought intensity
KW  - climate change
KW  - drought
KW  - events
KW  - Lake Malawi
KW  - Shire River
KW  - drought projections
KW  - South-Eastern
KW  - Africa
Y1  - 2022
U6  - https://doi.org/10.3389/frwa.2022.1041452
SN  - 2624-9375
VL  - 4
PB  - Frontiers Media
CY  - Lausanne
ER  - 
TY  - JOUR
A1  - Mtilatila, Lucy Mphatso Ng'ombe
A1  - Bronstert, Axel
A1  - Vormoor, Klaus Josef
T1  - Temporal evaluation and projections of meteorological droughts in the Greater Lake Malawi Basin, Southeast Africa
JF  - Frontiers in Water
N2  - The study examined the potential future changes of drought characteristics in the Greater Lake Malawi Basin in Southeast Africa. This region strongly depends on water resources to generate electricity and food. Future projections (considering both moderate and high emission scenarios) of temperature and precipitation from an ensemble of 16 bias-corrected climate model combinations were blended with a scenario-neutral response surface approach to analyses changes in: (i) the meteorological conditions, (ii) the meteorological water balance, and (iii) selected drought characteristics such as drought intensity, drought months, and drought events, which were derived from the Standardized Precipitation and Evapotranspiration Index. Changes were analyzed for a near-term (2021–2050) and far-term period (2071–2100) with reference to 1976–2005. The effect of bias-correction (i.e., empirical quantile mapping) on the ability of the climate model ensemble to reproduce observed drought characteristics as compared to raw climate projections was also investigated. Results suggest that the bias-correction improves the climate models in terms of reproducing temperature and precipitation statistics but not drought characteristics. Still, despite the differences in the internal structures and uncertainties that exist among the climate models, they all agree on an increase of meteorological droughts in the future in terms of higher drought intensity and longer events. Drought intensity is projected to increase between +25 and +50% during 2021–2050 and between +131 and +388% during 2071–2100. This translates into +3 to +5, and +7 to +8 more drought months per year during both periods, respectively. With longer lasting drought events, the number of drought events decreases. Projected droughts based on the high emission scenario are 1.7 times more severe than droughts based on the moderate scenario. That means that droughts in this region will likely become more severe in the coming decades. Despite the inherent high uncertainties of climate projections, the results provide a basis in planning and (water-)managing activities for climate change adaptation measures in Malawi. This is of particular relevance for water management issues referring hydro power generation and food production, both for rain-fed and irrigated agriculture.
KW  - meteorological drought
KW  - drought intensity
KW  - climate change
KW  - drought events
KW  - Lake Malawi
KW  - Shire River
KW  - drought projections
KW  - South-Eastern Africa
Y1  - 2022
U6  - https://doi.org/10.3389/frwa.2022.1041452
SN  - 2624-9375
SP  - 1
EP  - 16
PB  - Frontiers Media S.A.
CY  - Lausanne, Schweiz
ER  - 
TY  - GEN
A1  - Mtilatila, Lucy Mphatso Ng'ombe
A1  - Bronstert, Axel
A1  - Vormoor, Klaus Josef
T1  - Temporal evaluation and projections of meteorological droughts in the Greater Lake Malawi Basin, Southeast Africa
T2  - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe
N2  - The study examined the potential future changes of drought characteristics in the Greater Lake Malawi Basin in Southeast Africa. This region strongly depends on water resources to generate electricity and food. Future projections (considering both moderate and high emission scenarios) of temperature and precipitation from an ensemble of 16 bias-corrected climate model combinations were blended with a scenario-neutral response surface approach to analyses changes in: (i) the meteorological conditions, (ii) the meteorological water balance, and (iii) selected drought characteristics such as drought intensity, drought months, and drought events, which were derived from the Standardized Precipitation and Evapotranspiration Index. Changes were analyzed for a near-term (2021–2050) and far-term period (2071–2100) with reference to 1976–2005. The effect of bias-correction (i.e., empirical quantile mapping) on the ability of the climate model ensemble to reproduce observed drought characteristics as compared to raw climate projections was also investigated. Results suggest that the bias-correction improves the climate models in terms of reproducing temperature and precipitation statistics but not drought characteristics. Still, despite the differences in the internal structures and uncertainties that exist among the climate models, they all agree on an increase of meteorological droughts in the future in terms of higher drought intensity and longer events. Drought intensity is projected to increase between +25 and +50% during 2021–2050 and between +131 and +388% during 2071–2100. This translates into +3 to +5, and +7 to +8 more drought months per year during both periods, respectively. With longer lasting drought events, the number of drought events decreases. Projected droughts based on the high emission scenario are 1.7 times more severe than droughts based on the moderate scenario. That means that droughts in this region will likely become more severe in the coming decades. Despite the inherent high uncertainties of climate projections, the results provide a basis in planning and (water-)managing activities for climate change adaptation measures in Malawi. This is of particular relevance for water management issues referring hydro power generation and food production, both for rain-fed and irrigated agriculture.
T3  - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 1287 
KW  - meteorological drought
KW  - drought intensity
KW  - climate change
KW  - drought events
KW  - Lake Malawi
KW  - Shire River
KW  - drought projections
KW  - South-Eastern Africa
Y1  - 2022
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-571284
SN  - 1866-8372
IS  - 1287
ER  - 
TY  - JOUR
A1  - Bürger, Gerd
A1  - Pfister, A.
A1  - Bronstert, Axel
T1  - Temperature-Driven Rise in Extreme Sub-Hourly Rainfall
JF  - Journal of climate
N2  - Estimates of present and future extreme sub-hourly rainfall are derived from a daily spatial followed by a sub-daily temporal downscaling, the latter of which incorporates a novel, and crucial, temperature sensitivity. Specifically, daily global climate fields are spatially downscaled to local temperature T and precipitation P, which are then disaggregated to a temporal resolution of 10 min using a multiplicative random cascade model. The scheme is calibrated and validated with a group of 21 station records of 10-min resolution in Germany. The cascade model is used in the classical (denoted as MC) and in the new T-sensitive (MC+) version, which respects local Clausius-Clapeyron (CC) effects such as CC scaling. Extreme P is positively biased in both MC versions. Observed T sensitivity is absent in MC but well reproduced by MC+. Long-term positive trends in extreme sub-hourly P are generally more pronounced and more significant in MC+ than in MC. In units of 10-min rainfall, observed centennial trends in annual exceedance counts (EC) of P > 5 mm are +29% and in 3-yr return levels (RL) +27%. For the RCP4.5-simulated future, higher extremes are projected in both versions MC and MC+: per century, EC increases by 30% for MC and by 83% for MC+; the RL rises by 14% for MC and by 33% for MC+. Because the projected daily P trends are negligible, the sub-daily signal is mainly driven by local temperature.
KW  - Extreme events
KW  - Rainfall
KW  - Climate change
KW  - Statistical techniques
KW  - Time series
KW  - Stochastic models
Y1  - 2019
U6  - https://doi.org/10.1175/JCLI-D-19-0136.1
SN  - 0894-8755
SN  - 1520-0442
VL  - 32
IS  - 22
SP  - 7597
EP  - 7609
PB  - American Meteorological Soc.
CY  - Boston
ER  - 
TY  - JOUR
A1  - Schmidt, Lena Katharina
A1  - Francke, Till
A1  - Rottler, Erwin
A1  - Blume, Theresa
A1  - Schöber, Johannes
A1  - Bronstert, Axel
T1  - Suspended sediment and discharge dynamics in a glaciated alpine environment
BT  - identifying crucial areas and time periods on several spatial and temporal scales in the Ötztal, Austria
JF  - Earth surface dynamics
N2  - Glaciated high-alpine areas are fundamentally altered by climate change, with well-known implications for hydrology, e.g., due to glacier retreat, longer snow-free periods, and more frequent and intense summer rainstorms. While knowledge on how these hydrological changes will propagate to suspended sediment dynamics is still scarce, it is needed to inform mitigation and adaptation strategies. To understand the processes and source areas most relevant to sediment dynamics, we analyzed discharge and sediment dynamics in high temporal resolution as well as their patterns on several spatial scales, which to date few studies have done.

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

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

Our results extend the scientific knowledge on current hydro-sedimentological conditions in glaciated high-alpine areas and provide a baseline for studies on projected future changes in hydro-sedimentological system dynamics.
Y1  - 2022
U6  - https://doi.org/10.5194/esurf-10-653-2022
SN  - 2196-632X
SN  - 2196-6311
VL  - 10
IS  - 3
SP  - 653
EP  - 669
PB  - Copernicus Publications
CY  - Göttingen
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  - Mohr, Christian Heinrich
A1  - Montgomery, David R.
A1  - Huber, Anton
A1  - Bronstert, Axel
A1  - Iroume, Andres
T1  - Streamflow response in small upland catchments in the Chilean coastal range to the M-W 8.8 Maule earthquake on 27 February 2010
JF  - Journal of geophysical research : Earth surface
N2  - Hydrological response to earthquakes has long been observed, yet the mechanisms responsible still remain unclear and likely vary in space and time. This study explores the base flow response in small upland catchments of the Coastal Range of south-central Chile after the M-W 8.8 Maule earthquake of 27 February 2010. An initial decline in streamflow followed by an increase of up to 400% of the discharge measured immediately before the earthquake occurred, and diurnal streamflow oscillations intensified after the earthquake. Neither response time, nor time to maximum streamflow discharge showed any relationship with catchment topography or size, suggesting non-uniform release of water across the catchments. The fast response, unaffected stream water temperatures and a simple diffusion model point to the sandy saprolite as the source of the excess water. Base flow recession analysis reveals no evidence for substantial enhancement of lateral hydraulic conductivity in the saprolite after the earthquake. Seismic energy density reached similar to 170 J/m(3) for the main shock and similar to 0.9 J/m(3) for the aftershock, exceeding the threshold for liquefaction by undrained consolidation only during the main shock. Although increased hydraulic gradient due to ground acceleration-triggered, undrained consolidation is consistent with empirical magnitude-distance relationships for liquefaction, the lack of independent evidence for liquefaction means that enhanced vertical permeability (probably in combination with co-seismic near-surface dilatancy) cannot be excluded as a potential mechanism. Undrained consolidation may have released additional water from the saturated saprolite into the overlying soil, temporarily reducing water transfer to the creeks but enlarging the cross-section of the saturated zone, which in turn enhanced streamflow after establishment of a new hydraulic equilibrium. The enlarged saturated zone facilitated water uptake by roots and intensified evapotranspiration.
Y1  - 2012
U6  - https://doi.org/10.1029/2011JF002138
SN  - 0148-0227
VL  - 117
IS  - 23
PB  - American Geophysical Union
CY  - Washington
ER  - 
TY  - BOOK
A1  - Zehe, Erwin
A1  - Bolduan, Rainer
A1  - Bärdossy, Andräs
A1  - Bronstert, Axel
A1  - Plate, Erich
T1  - Stofftransport in einem Lösseinzugsgebiet: Experimentelle Evidenz und numerische Modellierung.
Y1  - 2004
SN  - 3-937758-18-6
ER  - 
TY  - JOUR
A1  - Brosinsky, Arlena
A1  - Förster, Saskia
A1  - Segl, Karl
A1  - Lopez-Tarazon, José Andrés
A1  - Pique, Gemma
A1  - Bronstert, Axel
T1  - Spectral fingerprinting: characterizing suspended sediment sources by the use of VNIR-SWIR spectral information
JF  - Journal of soils and sediments : protection, risk assessment and remediation
N2  - Knowledge of sediment sources is a prerequisite for sustainable management practices and may furthermore improve our understanding of water and sediment fluxes. Investigations have shown that a number of characteristic soil properties can be used as "fingerprints" to trace back the sources of river sediments. Spectral properties have recently been successfully used as such characteristics in fingerprinting studies. Despite being less labour-intensive than geochemical analyses, for example, spectroscopy allows measurements of small amounts of sediment material (> 60 mg), thus enabling inexpensive analyses even of intra-event variability. The focus of this study is on the examination of spectral properties of fluvial sediment samples to detect changes in source contributions, both between and within individual flood events.
 Sediment samples from the following three different origins were collected in the Isabena catchment (445 km(2)) in the central Spanish Pyrenees: (1) soil samples from the main potential source areas, (2) stored fine sediment from the channel bed once each season in 2011 and (3) suspended sediment samples during four flood events in autumn 2011 and spring 2012 at the catchment outlet as well as at several subcatchment outlets. All samples were dried and measured for spectral properties in the laboratory using an ASD spectroradiometer. Colour parameters and physically based features (e.g. organic carbon, iron oxide and clay content) were calculated from the spectra. Principal component analyses (PCA) were applied to all three types of samples to determine natural clustering of samples, and a mixing model was applied to determine source contributions.
 We found that fine sediment stored in the river bed seems to be mainly influenced by grain size and seasonal variability, while sampling location-and thus the effect of individual tributaries or subcatchments-seem to be of minor importance. Suspended sediment sources were found to vary between, as well as within, flood events; although badlands were always the major source. Forests and grasslands contributed little (< 10 %), and other sources (not further determinable) contributed up to 40 %. The analyses further suggested that sediment sources differ among the subcatchments and that subcatchments comprising relatively large proportions of badlands contributed most to the four flood events analyzed.
 Spectral fingerprints provide a rapid and cost-efficient alternative to conventional fingerprint properties. However, a combination of spectral and conventional fingerprint properties could potentially permit discrimination of a larger number of source types.
KW  - Isabena river
KW  - Mixing models
KW  - Northeast Spain
KW  - Sediment fingerprinting
KW  - Spectroscopy
KW  - Suspended sediment
Y1  - 2014
U6  - https://doi.org/10.1007/s11368-014-0927-z
SN  - 1439-0108
SN  - 1614-7480
VL  - 14
IS  - 12
SP  - 1965
EP  - 1981
PB  - Springer
CY  - Heidelberg
ER  - 
TY  - INPR
A1  - de Araujo, Jose Carlos
A1  - Batalla  Villanueva, Ramon J.
A1  - Bronstert, Axel
T1  - Special issue: analysis and modelling of sediment transfer in Mediterranean river basins
T2  - Journal of soils and sediments : protection, risk assessment and remediation
Y1  - 2014
U6  - https://doi.org/10.1007/s11368-014-1000-7
SN  - 1439-0108
SN  - 1614-7480
VL  - 14
IS  - 12
SP  - 1905
EP  - 1908
PB  - Springer
CY  - Heidelberg
ER  - 
TY  - JOUR
A1  - Jagdhuber, Thomas
A1  - Hajnsek, Irena
A1  - Bronstert, Axel
A1  - Papathanassiou, Konstantinos Panagiotis
T1  - Soil moisture estimation under low vegetation cover using a multi-angular polarimetric decomposition
JF  - IEEE transactions on geoscience and remote sensing
N2  - The estimation of volumetric soil moisture under low agricultural vegetation from fully polarimetric synthetic aperture radar (SAR) data at L-band using a multi-angular polarimetric decomposition is investigated. Radar polarimetry provides the framework to decompose the backscattered signal into different canonical scattering mechanisms referring to scattering contributions from the underlying soil and the vegetation cover. Multiangular observation diversity further increases the information space for soil moisture inversion enabling higher inversion rates and a stable inversion performance. The developed approach was applied on the multi-angular L-band data set acquired by German Aerospace Center's ESAR sensor as part of the OPAQUE campaign in 2008. The obtained results are compared against ground measurements collected by the OPAQUE team over a variety of vegetated agricultural fields. The validation of the estimated against ground measured soil moisture results in an root mean square error level of 6-8 vol.% including all test fields with a variety of crop types.
KW  - Multi-angular model-based decomposition
KW  - polarimetric SAR
KW  - soil moisture
Y1  - 2013
U6  - https://doi.org/10.1109/TGRS.2012.2209433
SN  - 0196-2892
VL  - 51
IS  - 4
SP  - 2201
EP  - 2215
PB  - Inst. of Electr. and Electronics Engineers
CY  - Piscataway
ER  - 
TY  - JOUR
A1  - Kneis, David
A1  - Förster, Saskia
A1  - Bronstert, Axel
T1  - Simulation of water quality in a flood detention area using models of different spatial discretization
N2  - Detention areas provide a means to lower peak discharges in rivers by temporarily storing excess water. In the case of extreme flood events, the storage effect reduces the risk of dike failures or extensive inundations for downstream reaches and near the site of abstraction. Due to the large amount of organic matter contained in the river water and the inundation of terrestrial vegetation in the detention area, a deterioration of water quality may occur. In particular, decay processes can cause a severe depletion of dissolved oxygen (DO) in the temporary water body. In this paper, we studied the potential of a water quality model to simulate the DO dynamics in a large but shallow detention area to be built at the Elbe River (Germany). Our focus was on examining the impact of spatial discretization on the model's performance and usability. Therefore, we used a zero-dimensional (OD) and a two-dimensional (2D) modeling approach in parallel. The two approaches solely differ in their spatial discretization, while conversion processes, parameters, and boundary conditions were kept identical. The dynamics of DO simulated by the two models are similar in the initial flooding period but diverge when the system starts to drain. The deviation can be attributed to the different spatial discretization of the two models, leading to different estimates of flow velocities and water depths. Only the 2D model can account for the impact of spatial variability on the evolution of state variables. However, its application requires high efforts for pre- and post-processing and significantly longer computation times. The 2D model is, therefore, not suitable for investigating various flood scenarios or for analyzing the impact of parameter uncertainty. For practical applications, we recommend to firstly set up a fast-running model of reduced spatial discretization, e.g. a OD model. Using this tool, the reliability of the simulation results should be checked by analyzing the parameter uncertainty of the water quality model. A particular focus may be on those parameters that are spatially variable and, therefore, believed to be better represented in a 2D approach. The benefit from the application of the more costly 2D model should be assessed, based on the analyses carried out with the OD model. A 2D model appears to be preferable only if the simulated detention area has a complex topography, flow velocities are highly variable in space, and the parameters of the water quality model are well known.
Y1  - 2009
UR  - http://www.sciencedirect.com/science/journal/03043800
U6  - https://doi.org/10.1016/j.ecolmodel.2009.04.006
SN  - 0304-3800
ER  - 
TY  - JOUR
A1  - Bronstert, Axel
A1  - Köhler, Birgit
T1  - Simulation der Einflüsse anthropogener Klimaänderungen auf die Hochwasserentstehung : eine Fallstudie in einem kleinen ländlichen Einzugsgebiet im Ostharz
Y1  - 2000
ER  - 
TY  - JOUR
A1  - Güntner, Andreas
A1  - Krol, Marten S.
A1  - de Arajo, José Carlos
A1  - Bronstert, Axel
T1  - Simple water balance modelling of surface reservoir systems in a large data-scarce semiarid region
N2  - Water resources in dryland areas are often provided by numerous surface reservoirs. As a basis for securing future water supply, the dynamics of reservoir systems need to be simulated for large river basins, accounting for environmental change and an increasing water demand. For the State of Ceara in semiarid Northeast Brazil, with several thousands of reservoirs, a simple deterministic water balance model is presented. Within a cascade-type approach, the reservoirs are grouped into six classes according to storage capacity, rules for flow routing between reservoirs of different size are defined, and water withdrawal and return flow due to human water use is accounted for. While large uncertainties in model applications exist, particularly in terms of reservoir operation rules, model validation against observed reservoir storage volumes shows that the approach is a reasonable simplification to assess surface water availability in large river basins. The results demonstrate the large impact of reservoir storage on downstream flow and stress the need for a coupled simulation of runoff generation, network redistribution and water use
Y1  - 2004
SN  - 0262-6667
ER  - 
TY  - JOUR
A1  - Mohr, Christian Heinrich
A1  - Manga, Michael
A1  - Wang, Chi-yuen
A1  - Kirchner, James W.
A1  - Bronstert, Axel
T1  - Shaking water out of soil
JF  - Geology
N2  - Moderate to large earthquakes can increase the amount of water flowing in streams. Previous interpretations and models assume that the extra water originates in the saturated zone. Here we show that earthquakes may also release water from the unsaturated zone when the seismic energy is sufficient to overcome the threshold of soil water retention. Soil water may then be released into aquifers, increasing streamflow. After the M8.8 Maule, Chile, earthquake, the discharge in some headwater catchments of the Chilean coastal range increased, and the amount of extra water in the discharge was similar to the total amount of water available for release from the unsaturated zone. Assuming rapid recharge of this water to the water table, a groundwater flow model that accounts for evapotranspiration and water released from soils can reproduce the increase in discharge as well as the enhanced diurnal discharge variations observed after the earthquake. Thus the unsaturated zone may play a previously unappreciated, and potentially significant, role in shallow hydrological responses to earthquakes.
Y1  - 2015
U6  - https://doi.org/10.1130/G36261.1
SN  - 0091-7613
SN  - 1943-2682
VL  - 43
IS  - 3
SP  - 207
EP  - 210
PB  - American Institute of Physics
CY  - Boulder
ER  - 
TY  - JOUR
A1  - Mohr, Christian Heinrich
A1  - Zimmermann, Andreas
A1  - Korup, Oliver
A1  - Iroume, A.
A1  - Francke, Till
A1  - Bronstert, Axel
T1  - Seasonal logging, process response, and geomorphic work
JF  - Earth surface dynamics
N2  - Deforestation is a prominent anthropogenic cause of erosive overland flow and slope instability, boosting rates of soil erosion and concomitant sediment flux. Conventional methods of gauging or estimating post-logging sediment flux often focus on annual timescales but overlook potentially important process response on shorter intervals immediately following timber harvest. We resolve such dynamics with non-parametric quantile regression forests (QRF) based on high-frequency (3 min) discharge measurements and sediment concentration data sampled every 30-60 min in similar-sized (similar to 0.1 km(2)) forested Chilean catchments that were logged during either the rainy or the dry season. The method of QRF builds on the random forest algorithm, and combines quantile regression with repeated random sub-sampling of both cases and predictors. The algorithm belongs to the family of decision-tree classifiers, which allow quantifying relevant predictors in high-dimensional parameter space. We find that, where no logging occurred, similar to 80% of the total sediment load was transported during extremely variable runoff events during only 5% of the monitoring period. In particular, dry-season logging dampened the relative role of these rare, extreme sediment-transport events by increasing load efficiency during more efficient moderate events. We show that QRFs outperform traditional sediment rating curves (SRCs) in terms of accurately simulating short-term dynamics of sediment flux, and conclude that QRF may reliably support forest management recommendations by providing robust simulations of post-logging response of water and sediment fluxes at high temporal resolution.
Y1  - 2014
U6  - https://doi.org/10.5194/esurf-2-117-2014
SN  - 2196-6311
SN  - 2196-632X
VL  - 2
IS  - 1
SP  - 117
EP  - 125
PB  - Copernicus
CY  - Göttingen
ER  - 
TY  - GEN
A1  - Pilz, Tobias
A1  - Delgado, José Miguel Martins
A1  - Voss, Sebastian
A1  - Vormoor, Klaus Josef
A1  - Francke, Till
A1  - Cunha Costa, Alexandre
A1  - Martins, Eduardo
A1  - Bronstert, Axel
T1  - Seasonal drought prediction for semiarid northeast Brazil
BT  - what is the added value of a process-based hydrological model?
T2  - Postprints der Universität Potsdam Mathematisch-Naturwissenschaftliche Reihe
N2  - The semiarid northeast of Brazil is one of the most densely populated dryland regions in the world and recurrently affected by severe droughts. Thus, reliable seasonal forecasts of streamflow and reservoir storage are of high value for water managers. Such forecasts can be generated by applying either hydrological models representing underlying processes or statistical relationships exploiting correlations among meteorological and hydrological variables. This work evaluates and compares the performances of seasonal reservoir storage forecasts derived by a process-based hydrological model and a statistical approach.

Driven by observations, both models achieve similar simulation accuracies. In a hindcast experiment, however, the accuracy of estimating regional reservoir storages was considerably lower using the process-based hydrological model, whereas the resolution and reliability of drought event predictions were similar by both approaches. Further investigations regarding the deficiencies of the process-based model revealed a significant influence of antecedent wetness conditions and a higher sensitivity of model prediction performance to rainfall forecast quality.

Within the scope of this study, the statistical model proved to be the more straightforward approach for predictions of reservoir level and drought events at regionally and monthly aggregated scales. However, for forecasts at finer scales of space and time or for the investigation of underlying processes, the costly initialisation and application of a process-based model can be worthwhile. Furthermore, the application of innovative data products, such as remote sensing data, and operational model correction methods, like data assimilation, may allow for an enhanced exploitation of the advanced capabilities of process-based hydrological models.
T3  - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 702 
KW  - Water Availability
KW  - Uncertainty Processor
KW  - Forecasting Framework
KW  - Sediment Transport
KW  - Reservoir Networks
KW  - Jaguaribe Basin
KW  - Climate
KW  - Precipitation
KW  - Nordeste
KW  - Connectivity
Y1  - 2019
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-427950
SN  - 1866-8372
IS  - 702
ER  - 
TY  - JOUR
A1  - Pilz, Tobias
A1  - Delgado, José Miguel Martins
A1  - Voss, Sebastian
A1  - Vormoor, Klaus Josef
A1  - Francke, Till
A1  - Cunha Costa, Alexandre
A1  - Martins, Eduardo
A1  - Bronstert, Axel
T1  - Seasonal drought prediction for semiarid northeast Brazil
BT  - what is the added value of a process-based hydrological model?
JF  - Hydrology and Earth System Sciences
N2  - The semiarid northeast of Brazil is one of the most densely populated dryland regions in the world and recurrently affected by severe droughts. Thus, reliable seasonal forecasts of streamflow and reservoir storage are of high value for water managers. Such forecasts can be generated by applying either hydrological models representing underlying processes or statistical relationships exploiting correlations among meteorological and hydrological variables. This work evaluates and compares the performances of seasonal reservoir storage forecasts derived by a process-based hydrological model and a statistical approach.

Driven by observations, both models achieve similar simulation accuracies. In a hindcast experiment, however, the accuracy of estimating regional reservoir storages was considerably lower using the process-based hydrological model, whereas the resolution and reliability of drought event predictions were similar by both approaches. Further investigations regarding the deficiencies of the process-based model revealed a significant influence of antecedent wetness conditions and a higher sensitivity of model prediction performance to rainfall forecast quality.

Within the scope of this study, the statistical model proved to be the more straightforward approach for predictions of reservoir level and drought events at regionally and monthly aggregated scales. However, for forecasts at finer scales of space and time or for the investigation of underlying processes, the costly initialisation and application of a process-based model can be worthwhile. Furthermore, the application of innovative data products, such as remote sensing data, and operational model correction methods, like data assimilation, may allow for an enhanced exploitation of the advanced capabilities of process-based hydrological models.
KW  - Water Availability
KW  - Uncertainty Processor
KW  - Forecasting Framework
KW  - Sediment Transport
KW  - Reservoir Networks
KW  - Jaguaribe Basin
KW  - Climate
KW  - Precipitation
KW  - Nordeste
KW  - Connectivity
Y1  - 2019
U6  - https://doi.org/10.5194/hess-23-1951-2019
SN  - 1027-5606
SN  - 1607-7938
VL  - 23
SP  - 1951
EP  - 1971
PB  - Copernicus Publications
CY  - Göttingen
ER  - 
TY  - JOUR
A1  - Müller, Eva Nora
A1  - van Schaik, Loes
A1  - Blume, Theresa
A1  - Bronstert, Axel
A1  - Carus, Jana
A1  - Fleckenstein, Jan H.
A1  - Fohrer, Nicola
A1  - Geissler, Katja
A1  - Gerke, Horst H.
A1  - Gräff, Thomas
A1  - Hesse, Cornelia
A1  - Hildebrandt, Anke
A1  - Hölker, Franz
A1  - Hunke, Philip
A1  - Körner, Katrin
A1  - Lewandowski, Jörg
A1  - Lohmann, Dirk
A1  - Meinikmann, Karin
A1  - Schibalski, Anett
A1  - Schmalz, Britta
A1  - Schröder-Esselbach, Boris
A1  - Tietjen, Britta
T1  - Scales, key aspects, feedbacks and challenges of ecohydrological research in Germany
JF  - Hydrologie und Wasserbewirtschaftung
N2  - Ecohydrology analyses the interactions of biotic and abiotic aspects of our ecosystems and landscapes. It is a highly diverse discipline in terms of its thematic and methodical research foci. This article gives an overview of current German ecohydrological research approaches within plant-animal-soil-systems, meso-scale catchments and their river networks, lake systems, coastal areas and tidal rivers. It discusses their relevant spatial and temporal process scales and different types of interactions and feedback dynamics between hydrological and biotic processes and patterns. The following topics are considered key challenges: innovative analysis of the interdisciplinary scale continuum, development of dynamically coupled model systems, integrated monitoring of coupled processes at the interface and transition from basic to applied ecohydrological science to develop sustainable water and land resource management strategies under regional and global change.
KW  - Coastal regions
KW  - drylands
KW  - ecohydrological modelling
KW  - feedback
KW  - hyporheic zone
KW  - meso-scale ecosystems
KW  - plant-animal-soil-system
KW  - river networks
Y1  - 2014
U6  - https://doi.org/10.5675/HyWa_2014,4_2
SN  - 1439-1783
VL  - 58
IS  - 4
SP  - 221
EP  - 240
PB  - Bundesanst. für Gewässerkunde
CY  - Koblenz
ER  - 
TY  - JOUR
A1  - Mohr, Christian Heinrich
A1  - Coppus, Ruben
A1  - Iroume, Andres
A1  - Huber, Anton
A1  - Bronstert, Axel
T1  - Runoff generation and soil erosion processes after clear cutting
JF  - Journal of geophysical research : Earth surface
N2  - Timber harvesting by clear cutting is known to impose environmental impacts, including severe disturbance of the soil hydraulic properties which intensify the frequency and magnitude of surface runoff and soil erosion. However, it remains unanswered if harvest areas act as sources or sinks for runoff and soil erosion and whether such behavior operates in a steady state or evolves through time. For this purpose, 92 small-scale rainfall simulations of different intensities were carried out under pine plantation conditions and on two clear-cut harvest areas of different age. Nonparametrical Random Forest statistical models were set up to quantify the impact of environmental variables on the hydrological and erosion response. Regardless of the applied rainfall intensity, runoff always initiated first and yielded most under plantation cover. Counter to expectations, infiltration rates increased after logging activities. Once a threshold rainfall intensity of 20mm/h was exceeded, the younger harvest area started to act as a source for both runoff and erosion after connectivity was established, whereas it remained a sink under lower applied rainfall intensities. The results suggest that the impact of microtopography on surface runoff connectivity and water-repellent properties of the topsoil act as first-order controls for the hydrological and erosion processes in such environments. Fast rainfall-runoff response, sediment-discharge-hystereses, and enhanced postlogging groundwater recharge at catchment scale support our interpretation. At the end, we show the need to account for nonstationary hydrological and erosional behavior of harvest areas, a fact previously unappreciated in predictive models.
KW  - infiltration
KW  - runoff
KW  - erosion
KW  - connectivity
KW  - rainfall simulation
KW  - catchment
Y1  - 2013
U6  - https://doi.org/10.1002/jgrf.20047
SN  - 2169-9003
VL  - 118
IS  - 2
SP  - 814
EP  - 831
PB  - American Geophysical Union
CY  - Washington
ER  - 
TY  - JOUR
A1  - Bronstert, Axel
A1  - Menzel, Lucas
A1  - Middelkoop, H.
A1  - de Roo, A. P.
A1  - Van Beek, E.
T1  - River basin research and management : integrated modelling and investigation of land-use impacts on the hydrological cycle
Y1  - 2001
ER  - 
TY  - JOUR
A1  - Güntner, Andreas
A1  - Bronstert, Axel
T1  - Representation of landscape variability and lateral redistribution processes for large-scale hydrological modelling in semi-arid areas
N2  - The spatial variability of landscape features such as topography, soils and vegetation defines the spatial pattern of hydrological state variables like soil moisture. Spatial variability thereby controls the functional behaviour of the landscape in terms of its runoff response. A consequence of spatial variability is that exchange processes between landscape patches can occur at various spatial scales ranging from the plot to the basin scale. In semi-arid areas, the lateral redistribution of surface runoff between adjacent landscape patches is an important process. For applications to large river basins of 10(4)-10(5) km(2) in size, a multi-scale landscape discretization scheme is presented in this paper. The landscape is sub-divided into modelling units within a hierarchy of spatial scale levels. By delineating areas characterized by a typical toposequence, organised and random variability of landscape characteristics is captured in the model. Using runoff-runon relationships with transition frequencies based on areal fractions of modelling units, lateral surface and subsurface water fluxes between modelling units at the hillslope scale are represented. Thus, the new approach allows for a manageable description of interactions between fine-scale landscape features for inclusion in coarse-scale models. Model applications for the State of Ceara (148,000 km(2)) in the north- east of Brazil demonstrate the importance of taking into account landscape variability and interactions between landscape patches in a semi-arid environment. Using mean landscape characteristics leads to a considerable underestimation of infiltration-excess surface runoff and total simulated runoff. Re-infiltration of surface runoff and lateral redistribution processes between landscape patches cause a reduction of runoff volumes at the basin scale and contribute to the amplification of variations in runoff volumes relative to variations in rainfall volumes for semi-arid areas. (C) 2004 Elsevier B.V. All rights reserved
Y1  - 2004
SN  - 0022-1694
ER  - 
TY  - JOUR
A1  - Schmidt, Lena Katharina
A1  - Francke, Till
A1  - Grosse, Peter Martin
A1  - Mayer, Christoph
A1  - Bronstert, Axel
T1  - Reconstructing five decades of sediment export from two glacierized high-alpine catchments in Tyrol, Austria, using nonparametric regression
JF  - Hydrology and earth system sciences : HESS
N2  - Knowledge on the response of sediment export to recent climate change in glacierized areas in the European Alps is limited, primarily because long-term records of suspended sediment concentrations (SSCs) are scarce. Here we tested the estimation of sediment export of the past five decades using quantile regression forest (QRF), a nonparametric, multivariate regression based on random forest. The regression builds on short-term records of SSCs and long records of the most important hydroclimatic drivers (discharge, precipitation and air temperature - QPT). We trained independent models for two nested and partially glacier-covered catchments, Vent (98 km(2)) and Vernagt (11.4 km(2)), in the upper otztal in Tyrol, Austria (1891 to 3772 m a.s.l.), where available QPT records start in 1967 and 1975. To assess temporal extrapolation ability, we used two 2-year SSC datasets at gauge Vernagt, which are almost 20 years apart, for a validation. For Vent, we performed a five-fold cross-validation on the 15 years of SSC measurements. Further, we quantified the number of days where predictors exceeded the range represented in the training dataset, as the inability to extrapolate beyond this range is a known limitation of QRF. Finally, we compared QRF performance to sediment rating curves (SRCs). We analyzed the modeled sediment export time series, the predictors and glacier mass balance data for trends (Mann-Kendall test and Sen's slope estimator) and step-like changes (using the widely applied Pettitt test and a complementary Bayesian approach).Our validation at gauge Vernagt demonstrated that QRF performs well in estimating past daily sediment export (Nash-Sutcliffe efficiency (NSE) of 0.73) and satisfactorily for SSCs (NSE of 0.51), despite the small training dataset. The temporal extrapolation ability of QRF was superior to SRCs, especially in periods with high-SSC events, which demonstrated the ability of QRF to model threshold effects. Days with high SSCs tended to be underestimated, but the effect on annual yields was small. Days with predictor exceedances were rare, indicating a good representativity of the training dataset. Finally, the QRF reconstruction models outperformed SRCs by about 20 percent points of the explained variance.Significant positive trends in the reconstructed annual suspended sediment yields were found at both gauges, with distinct step-like increases around 1981. This was linked to increased glacier melt, which became apparent through step-like increases in discharge at both gauges as well as change points in mass balances of the two largest glaciers in the Vent catchment. We identified exceptionally high July temperatures in 1982 and 1983 as a likely cause. In contrast, we did not find coinciding change points in precipitation. Opposing trends at the two gauges after 1981 suggest different timings of "peak sediment". We conclude that, given large-enough training datasets, the presented QRF approach is a promising tool with the ability to deepen our understanding of the response of high-alpine areas to decadal climate change.
Y1  - 2023
U6  - https://doi.org/10.5194/hess-27-1841-2023
SN  - 1027-5606
SN  - 1607-7938
VL  - 27
IS  - 9
SP  - 1841
EP  - 1863
PB  - Copernicus
CY  - Göttingen
ER  - 
TY  - JOUR
A1  - Bronstert, Axel
T1  - Rainfall-runoff modelling for assessing impacts of climate and land-use change
Y1  - 2004
ER  - 
TY  - JOUR
A1  - Bronstert, Axel
A1  - Fritsch, Uta
A1  - Leonhardt, H.
A1  - Niehoff, Daniel
T1  - Quantifizierung des Einflusses von Landnutzungs- und Klimaänderungen auf die Hochwasserentstehung am Beispiel ausgewählter Flussgebiete
Y1  - 2001
ER  - 
TY  - JOUR
A1  - Katzenmaier, Daniel
A1  - Fritsch, Uta
A1  - Bronstert, Axel
T1  - Quantifizierung des Einflusses von Landnutzung und dezentraler Versickerung auf die Hochwasserentstehung
Y1  - 2001
SN  - 3-503-06021-9
ER  - 
TY  - JOUR
A1  - Bronstert, Axel
A1  - Fritsch, Uta
A1  - Katzenmaier, Daniel
A1  - Bismuth, Christine
T1  - Quantification of the influence of the land-surface and river training on flood discharge of the Rhine Basin
Y1  - 2000
ER  - 
TY  - JOUR
A1  - Huang, Shaochun
A1  - Hattermann, Fred
A1  - Krysanova, Valentina
A1  - Bronstert, Axel
T1  - Projections of climate change impacts on river flood conditions in Germany by combining three different RCMs with a regional eco-hydrological model
JF  - Climatic change : an interdisciplinary, intern. journal devoted to the description, causes and implications of climatic change
N2  - A general increase in precipitation has been observed in Germany in the last century, and potential changes in flood generation and intensity are now at the focus of interest. The aim of the paper is twofold: a) to project the future flood conditions in Germany accounting for various river regimes (from pluvial to nival-pluvial regimes) and under different climate scenarios (the high, A2, low, B1, and medium, A1B, emission scenarios) and b) to investigate sources of uncertainty generated by climate input data and regional climate models. Data of two dynamical Regional Climate Models (RCMs), REMO (REgional Model) and CCLM (Cosmo-Climate Local Model), and one statistical-empirical RCM, Wettreg (Wetterlagenbasierte Regionalisierungsmethode: weather-type based regionalization method), were applied to drive the eco-hydrological model SWIM (Soil and Water Integrated Model), which was previously validated for 15 gauges in Germany. At most of the gauges, the 95 and 99 percentiles of the simulated discharge using SWIM with observed climate data had a good agreement with the observed discharge for 1961-2000 (deviation within +/- 10 %). However, the simulated discharge had a bias when using RCM climate as input for the same period. Generalized Extreme Value (GEV) distributions were fitted to the annual maximum series of river runoff for each realization for the control and scenario periods, and the changes in flood generation over the whole simulation time were analyzed. The 50-year flood values estimated for two scenario periods (2021-2060, 2061-2100) were compared to the ones derived from the control period using the same climate models. The results driven by the statistical-empirical model show a declining trend in the flood level for most rivers, and under all climate scenarios. The simulations driven by dynamical models give various change directions depending on region, scenario and time period. The uncertainty in estimating high flows and, in particular, extreme floods remains high, due to differences in regional climate models, emission scenarios and multi-realizations generated by RCMs.
Y1  - 2013
U6  - https://doi.org/10.1007/s10584-012-0586-2
SN  - 0165-0009
SN  - 1573-1480
VL  - 116
IS  - 3-4
SP  - 631
EP  - 663
PB  - Springer
CY  - Dordrecht
ER  - 
TY  - GEN
A1  - Rottler, Erwin
A1  - Bronstert, Axel
A1  - Bürger, Gerd
A1  - Rakovec, Oldrich
T1  - Projected changes in Rhine River flood seasonality under global warming
T2  - Postprints der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe
N2  - Climatic change alters the frequency and intensity of natural hazards. In order to assess potential future changes in flood seasonality in the Rhine River Basin, we analyse changes in streamflow, snowmelt, precipitation, and evapotranspiration at 1.5, 2.0 and 3.0 ◦C global warming levels. The mesoscale Hydrological Model (mHM) forced with an ensemble of climate projection scenarios (five general circulation models under three representative concentration pathways) is used to simulate the present and future climate conditions of both, pluvial and nival hydrological regimes. Our results indicate that the interplay between changes in snowmelt- and rainfall-driven runoff is crucial to understand changes in streamflow maxima in the Rhine River. Climate projections suggest that future changes in flood characteristics in the entire Rhine River are controlled by both, more intense precipitation events and diminishing snow packs. The nature of this interplay defines the type of change in runoff peaks. On the sub-basin level (the Moselle River), more intense rainfall during winter is mostly counterbalanced by reduced snowmelt contribution to the streamflow. In the High Rhine (gauge at Basel), the strongest increases in streamflow maxima show up during winter, when strong increases in liquid precipitation intensity encounter almost unchanged snowmelt-driven runoff. The analysis of snowmelt events suggests that at no point in time during the snowmelt season, a warming climate results in an increase in the risk of snowmelt-driven flooding. We do not find indications of a transient merging of pluvial and nival floods due to climate warming.
T3  - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 1164 
Y1  - 2020
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-522962
SN  - 1866-8372
ER  - 
TY  - JOUR
A1  - Rottler, Erwin
A1  - Bronstert, Axel
A1  - Bürger, Gerd
A1  - Rakovec, Oldrich
T1  - Projected changes in Rhine River flood seasonality under global warming
JF  - Hydrology and earth system sciences : HESS / European Geosciences Union
N2  - Climatic change alters the frequency and intensity of natural hazards. In order to assess potential future changes in flood seasonality in the Rhine River Basin, we analyse changes in streamflow, snowmelt, precipitation, and evapotranspiration at 1.5, 2.0 and 3.0 ◦C global warming levels. The mesoscale Hydrological Model (mHM) forced with an ensemble of climate projection scenarios (five general circulation models under three representative concentration pathways) is used to simulate the present and future climate conditions of both, pluvial and nival hydrological regimes. Our results indicate that the interplay between changes in snowmelt- and rainfall-driven runoff is crucial to understand changes in streamflow maxima in the Rhine River. Climate projections suggest that future changes in flood characteristics in the entire Rhine River are controlled by both, more intense precipitation events and diminishing snow packs. The nature of this interplay defines the type of change in runoff peaks. On the sub-basin level (the Moselle River), more intense rainfall during winter is mostly counterbalanced by reduced snowmelt contribution to the streamflow. In the High Rhine (gauge at Basel), the strongest increases in streamflow maxima show up during winter, when strong increases in liquid precipitation intensity encounter almost unchanged snowmelt-driven runoff. The analysis of snowmelt events suggests that at no point in time during the snowmelt season, a warming climate results in an increase in the risk of snowmelt-driven flooding. We do not find indications of a transient merging of pluvial and nival floods due to climate warming.
Y1  - 2020
U6  - https://doi.org/10.5194/hess-25-2353-2021
SN  - 1607-7938
SN  - 1027-5606
VL  - 25
IS  - 5
SP  - 2353
EP  - 2371
PB  - Copernicus Publications
CY  - Göttingen
ER  - 
TY  - JOUR
A1  - Güntner, Andreas
A1  - Bronstert, Axel
T1  - Process-based modelling of large-scale water availability in a semi-arid environment : process representation and scaling issues
Y1  - 2002
ER  - 
TY  - JOUR
A1  - Bronstert, Axel
A1  - de Araujo, Josè Carlos
A1  - Batalla  Villanueva, Ramon J.
A1  - Costa, Alexandre Cunha
A1  - Delgado, José Miguel Martins
A1  - Francke, Till
A1  - Förster, Saskia
A1  - Guentner, Andreas
A1  - Lopez-Tarazon, José Andrés
A1  - Mamede, George Leite
A1  - Medeiros, Pedro Henrique Augusto
A1  - Mueller, Eva
A1  - Vericat, Damia
T1  - Process-based modelling of erosion, sediment transport and reservoir siltation in mesoscale semi-arid catchments
JF  - Journal of soils and sediments : protection, risk assessment and remediation
N2  - To support scientifically sound water management in dryland environments a modelling system has been developed for the quantitative assessment of water and sediment fluxes in catchments, transport in the river system, and retention in reservoirs. The spatial scale of interest is the mesoscale because this is the scale most relevant for management of water and land resources.
 This modelling system comprises process-oriented hydrological components tailored for dryland characteristics coupled with components comprising hillslope erosion, sediment transport and reservoir deposition processes. The spatial discretization is hierarchically designed according to a multi-scale concept to account for particular relevant process scales. The non-linear and partly intermittent run-off generation and sediment dynamics are dealt with by accounting for connectivity phenomena at the intersections of landscape compartments. The modelling system has been developed by means of data from nested research catchments in NE-Spain and in NE-Brazil.
 In the semi-arid NE of Brazil sediment retention along the topography is the main process for sediment retention at all scales, i.e. the sediment delivery is transport limited. This kind of deposition retains roughly 50 to 60 % of eroded sediment, maintaining a similar deposition proportion in all spatial scales investigated. On the other hand, the sediment retained in reservoirs is clearly related to the scale, increasing with catchment area. With increasing area, there are more reservoirs, increasing the possibility of deposition. Furthermore, the area increase also promotes an increase in flow volume, favouring the construction of larger reservoirs, which generally overflow less frequently and retain higher sediment fractions. The second example comprises a highly dynamic Mediterranean catchment in NE-Spain with nested sub-catchments and reveals the full dynamics of hydrological, erosion and deposition features. The run-off modelling performed well with only some overestimation during low-flow periods due to the neglect of water losses along the river. The simulated peaks in sediment flux are reproduced well, while low-flow sediment transport is less well captured, due to the disregard of sediment remobilization in the riverbed during low flow.
 This combined observation and modelling study deepened the understanding of hydro-sedimentological systems characterized by flashy run-off generation and by erosion and sediment transport pulses through the different landscape compartments. The connectivity between the different landscape compartments plays a very relevant role, regarding both the total mass of water and sediment transport and the transport time through the catchment.
KW  - Connectivity
KW  - Deposition
KW  - Erosion
KW  - Modelling
KW  - Sediment transfer
KW  - Semi-arid
Y1  - 2014
U6  - https://doi.org/10.1007/s11368-014-0994-1
SN  - 1439-0108
SN  - 1614-7480
VL  - 14
IS  - 12
SP  - 2001
EP  - 2018
PB  - Springer
CY  - Heidelberg
ER  - 
TY  - JOUR
A1  - van Schaik, N. Loes M. B.
A1  - Bronstert, Axel
A1  - de Jong, S. M.
A1  - Jetten, V. G.
A1  - van Dam, J. C.
A1  - Ritsema, C. J.
A1  - Schnabel, Susanne
T1  - Process-based modelling of a headwater catchment in a semi-arid area: the influence of macropore flow
JF  - Hydrological processes
N2  - Subsurface stormflow is thought to occur mainly in humid environments with steep terrains. However, in semi-arid areas, preferential flow through macropores can also result in a significant contribution of subsurface stormflow to catchment runoff for varying catchment conditions. Most hydrological models neglect this important subsurface preferential flow. Here, we use the process-oriented hydrological model Hillflow-3D, which includes a macropore flow approach, to simulate rainfall-runoff in the semi-arid Parapunos catchment in Spain, where macropore flow was observed in previous research. The model was extended for this study to account for sorptivity under very dry soil conditions. The results of the model simulations with and without macropore flow are compared. Both model versions give reasonable results for average rainfall situations, although the approach with the macropore concept provides slightly better results. The model results for scenarios of extreme rainfall events (>13.3mm30min(-1)) however show large differences between the versions with and without macropores. These model results compared with measured rainfall-runoff data show that the model with the macropore concept is better. Our conclusion is that preferential flow is important in controlling surface runoff in case of specific, high intensity rainfall events. Therefore, preferential flow processes must be included in hydrological models where we know that preferential flow occurs. Hydrological process models with a less detailed process description may fit observed average events reasonably well but can result in erroneous predictions for more extreme events. Copyright (c) 2013 John Wiley & Sons, Ltd.
KW  - process based
KW  - macropore flow
KW  - catchment scale
KW  - modelling
KW  - semi-arid area
Y1  - 2014
U6  - https://doi.org/10.1002/hyp.10086
SN  - 0885-6087
SN  - 1099-1085
VL  - 28
IS  - 24
SP  - 5805
EP  - 5816
PB  - Wiley-Blackwell
CY  - Hoboken
ER  - 
TY  - JOUR
A1  - Gräff, Thomas
A1  - Zehe, Erwin
A1  - Reusser, Dominik
A1  - Lueck, Erika
A1  - Schroeder, Boris
A1  - Wenk, Gerald
A1  - John, Hermann
A1  - Bronstert, Axel
T1  - Process identification through rejection of model structures in a mid-mountainous rural catchment : observations of rainfall-runoff response, geophysical conditions and model inter-comparison
N2  - The intention of the presented study is to gain a better understanding of the mechanisms that caused the bimodal rainfall-runoff responses which occurred up to the mid-1970s regularly in the Schafertal catchment and vanished after the onset of mining activities. Understanding, this process is a first step to understanding the ongoing hydrological change in this area. It is hypothesized that either subsurface stormflow, or fast displacement of groundwater, could cause the second delayed peak. A top-down analysis of rainfall-runoff data, field observations as well as process modelling are combined within a rejectionistic framework. A statistical analysis is used to test whether different predictors. which characterize the forcing. near surface water content and deeper subsurface store, allow the prediction of the type of rainfall-runoff response. Regression analysis is used with generalized linear models Lis they can deal with non-Gaussian error distributions Lis well its a non-stationary variance. The analysis reveals that the dominant predictors are the pre-event discharge (proxy of state of the groundwater store) and the precipitation amount, In the field campaign, the subsurface at a representative hillslope was investigated by means of electrical resistivity tomography in order to identify possible strata as flow paths for subsurface stormflow. A low resistivity in approximately 4 in depth-either due to a less permeable layer or the groundwater surface-was detected. The former Could serve as a flow path for subsurface stormflow. Finally, the physical-based hydrological model CATFLOW and the groundwater model FEFLOW are compared with respect to their ability to reproduce the bimodal runoff responses. The groundwater model is able to reproduce the observations, although it uses only an abstract representation of the hillslopes. Process model analysis as well Lis statistical analysis strongly suggest that fast displacement of groundwater is the dominant process underlying the bimodal runoff reactions.
Y1  - 2009
UR  - http://www3.interscience.wiley.com/journal/4125/home
U6  - https://doi.org/10.1002/Hyp.7171
SN  - 0885-6087
ER  - 
TY  - JOUR
A1  - Bronstert, Axel
T1  - Probleme, Grenzen und Herausforderungen der hydrologischen Modellierung: Wasserhaushalt und Abfluss
Y1  - 2004
ER  - 
TY  - JOUR
A1  - Costa, Alexandre Cunha
A1  - Bronstert, Axel
A1  - Kneis, David
T1  - Probabilistic flood forecasting for a mountainous headwater catchment using a nonparametric stochastic dynamic approach
JF  - Hydrological sciences journal = Journal des sciences hydrologiques
N2  - Hydrological models are commonly used to perform real-time runoff forecasting for flood warning. Their application requires catchment characteristics and precipitation series that are not always available. An alternative approach is nonparametric modelling based only on runoff series. However, the following questions arise: Can nonparametric models show reliable forecasting? Can they perform as reliably as hydrological models? We performed probabilistic forecasting one, two and three hours ahead for a runoff series, with the aim of ascribing a probability density function to predicted discharge using time series analysis based on stochastic dynamics theory. The derived dynamic terms were compared to a hydrological model, LARSIM. Our procedure was able to forecast within 95% confidence interval 1-, 2- and 3-h ahead discharge probability functions with about 1.40 m(3)/s of range and relative errors (%) in the range [-30; 30]. The LARSIM model and the best nonparametric approaches gave similar results, but the range of relative errors was larger for the nonparametric approaches.
KW  - streamflow probabilistic forecasting
KW  - time series analysis
KW  - stochastic dynamical systems
KW  - parametric and nonparametric comparison
Y1  - 2012
U6  - https://doi.org/10.1080/02626667.2011.637043
SN  - 0262-6667
VL  - 57
IS  - 1
SP  - 10
EP  - 25
PB  - Routledge, Taylor & Francis Group
CY  - Abingdon
ER  - 
TY  - JOUR
A1  - Bronstert, Axel
A1  - Creutzfeldt, Benjamin
A1  - Gräff, Thomas
A1  - Hajnsek, Irena
A1  - Heistermann, Maik
A1  - Itzerott, Sibylle
A1  - Jagdhuber, Thomas
A1  - Kneis, David
A1  - Lueck, Erika
A1  - Reusser, Dominik
A1  - Zehe, Erwin
T1  - Potentials and constraints of different types of soil moisture observations for flood simulations in headwater catchments
JF  - Natural hazards : journal of the International Society for the Prevention and Mitigation of Natural Hazards
N2  - Flood generation in mountainous headwater catchments is governed by rainfall intensities, by the spatial distribution of rainfall and by the state of the catchment prior to the rainfall, e. g. by the spatial pattern of the soil moisture, groundwater conditions and possibly snow. The work presented here explores the limits and potentials of measuring soil moisture with different methods and in different scales and their potential use for flood simulation. These measurements were obtained in 2007 and 2008 within a comprehensive multi-scale experiment in the Weisseritz headwater catchment in the Ore-Mountains, Germany. The following technologies have been applied jointly thermogravimetric method, frequency domain reflectometry (FDR) sensors, spatial time domain reflectometry (STDR) cluster, ground-penetrating radar (GPR), airborne polarimetric synthetic aperture radar (polarimetric SAR) and advanced synthetic aperture radar (ASAR) based on the satellite Envisat. We present exemplary soil measurement results, with spatial scales ranging from point scale, via hillslope and field scale, to the catchment scale. Only the spatial TDR cluster was able to record continuous data. The other methods are limited to the date of over-flights (airplane and satellite) or measurement campaigns on the ground. For possible use in flood simulation, the observation of soil moisture at multiple scales has to be combined with suitable hydrological modelling, using the hydrological model WaSiM-ETH. Therefore, several simulation experiments have been conducted in order to test both the usability of the recorded soil moisture data and the suitability of a distributed hydrological model to make use of this information. The measurement results show that airborne-based and satellite-based systems in particular provide information on the near-surface spatial distribution. However, there are still a variety of limitations, such as the need for parallel ground measurements (Envisat ASAR), uncertainties in polarimetric decomposition techniques (polarimetric SAR), very limited information from remote sensing methods about vegetated surfaces and the non-availability of continuous measurements. The model experiments showed the importance of soil moisture as an initial condition for physically based flood modelling. However, the observed moisture data reflect the surface or near-surface soil moisture only. Hence, only saturated overland flow might be related to these data. Other flood generation processes influenced by catchment wetness in the subsurface such as subsurface storm flow or quick groundwater drainage cannot be assessed by these data. One has to acknowledge that, in spite of innovative measuring techniques on all spatial scales, soil moisture data for entire vegetated catchments are still today not operationally available. Therefore, observations of soil moisture should primarily be used to improve the quality of continuous, distributed hydrological catchment models that simulate the spatial distribution of moisture internally. Thus, when and where soil moisture data are available, they should be compared with their simulated equivalents in order to improve the parameter estimates and possibly the structure of the hydrological model.
KW  - Soil moisture
KW  - Remote sensing
KW  - Hydrological modelling
KW  - Flood forecasting
KW  - Soil moisture measurement comparison
Y1  - 2012
U6  - https://doi.org/10.1007/s11069-011-9874-9
SN  - 0921-030X
SN  - 1573-0840
VL  - 60
IS  - 3
SP  - 879
EP  - 914
PB  - Springer
CY  - New York
ER  - 
TY  - JOUR
A1  - Zehe, Erwin
A1  - Gräff, Thomas
A1  - Morgner, Markus
A1  - Bauer, Andreas
A1  - Bronstert, Axel
T1  - Plot and field scale soil moisture dynamics and subsurface wetness control on runoff generation in a headwater in the Ore Mountains
N2  - This study presents an application of an innovative sampling strategy to assess soil moisture dynamics in a headwater of the Weisseritz in the German eastern Ore Mountains. A grassland site and a forested site were instrumented with two Spatial TDR clusters (STDR) that consist of 39 and 32 coated TDR probes of 60 cm length. Distributed time series of vertically averaged soil moisture data from both sites/ensembles were analyzed by statistical and geostatistical methods. Spatial variability and the spatial mean at the forested site were larger than at the grassland site. Furthermore, clustering of TDR probes in combination with long-term monitoring allowed identification of average spatial covariance structures at the small field scale for different wetness states. The correlation length of soil water content as well as the sill to nugget ratio at the grassland site increased with increasing average wetness and but, in contrast, were constant at the forested site. As soil properties at both the forested and grassland sites are extremely variable, this suggests that the correlation structure at the forested site is dominated by the pattern of throughfall and interception. We also found a very strong correlation between antecedent soil moisture at the forested site and runoff coefficients of rainfall-runoff events observed at gauge Rehefeld. Antecedent soil moisture at the forest site explains 92% of the variability in the runoff coefficients. By combining these results with a recession analysis we derived a first conceptual model of the dominant runoff mechanisms operating in this catchment. Finally, we employed a physically based hydrological model to shed light on the controls of soil- and plant morphological parameters on soil average soil moisture at the forested site and the grassland site, respectively. A homogeneous soil setup allowed, after fine tuning of plant morphological parameters, most of the time unbiased predictions of the observed average soil conditions observed at both field sites. We conclude that the proposed sampling strategy of clustering TDR probes is suitable to assess unbiased average soil moisture dynamics in critical functional units, in this case the forested site, which is a much better predictor for event scale runoff formation than pre-event discharge. Long term monitoring of such critical landscape elements could maybe yield valuable information for flood warning in headwaters. We thus think that STDR provides a good intersect of the advantages of permanent sampling and spatially highly resolved soil moisture sampling using mobile rods.
Y1  - 2010
UR  - http://www.copernicus.org/EGU/hess/hess.html
U6  - https://doi.org/10.5194/hess-14-873-2010
SN  - 1027-5606
ER  - 
TY  - JOUR
A1  - Zehe, Erwin
A1  - Gräff, Thomas
A1  - Morgner, Markus
A1  - Bauer, Andreas
A1  - Bronstert, Axel
T1  - Plot and field scale soil moisture dynamics and subsurface wetness control on runoff generation in a headwater in the Ore Mountains
N2  - This study presents an application of an innovative sampling strategy to assess soil moisture dynamics in a headwater of the Weißeritz in the German eastern Ore Mountains. A grassland site and a forested site were instrumented with two Spatial TDR clusters (STDR) that consist of 39 and 32 coated TDR probes of 60 cm length. Distributed time series of vertically averaged soil moisture data from both sites/ensembles were analyzed by statistical and geostatistical methods. Spatial variability and the spatial mean at the forested site were larger than at the grassland site. Furthermore, clustering of TDR probes in combination with long-term monitoring allowed identification of average spatial covariance structures at the small field scale for different wetness states. The correlation length of soil water content as well as the sill to nugget ratio at the grassland site increased with increasing average wetness and but, in contrast, were constant at the forested site. As soil properties at both the forested and grassland sites are extremely variable, this suggests that the correlation structure at the forested site is dominated by the pattern of throughfall and interception. We also found a strong correlation between average soil moisture dynamics and runoff coefficients of rainfall-runoff events observed at gauge Rehefeld, which explains almost as much variability in the runoff coefficients as pre-event discharge. By combining these results with a recession analysis we derived a first conceptual model of the dominant runoff mechanisms operating in this catchment. Finally, long term simulations with a physically based hydrological model were in good/acceptable accordance with the time series of spatial average soil water content observed at the forested site and the grassland site, respectively. Both simulations used a homogeneous soil setup that closely reproduces observed average soil conditions observed at the field sites. This corroborates the proposed sampling strategy of clustering TDR probes in typical functional units is a promising technique to explore the soil moisture control on runoff generation. Long term monitoring of such sites could maybe yield valuable information for flood warning. The sampling strategy helps furthermore to unravel different types of soil moisture variability.
Y1  - 2008
ER  - 
TY  - JOUR
A1  - Kumar, Satish
A1  - Guntu, Ravi Kumar
A1  - Agarwal, Ankit
A1  - Villuri, Vasant Govind Kumar
A1  - Pasupuleti, Srinivas
A1  - Kaushal, Deo Raj
A1  - Gosian, Ashwin Kumar
A1  - Bronstert, Axel
T1  - Multi-objective optimization for stormwater management by green-roofs and infiltration trenches to reduce urban flooding in central Delhi
JF  - Journal of hydrology
N2  - Urban surface runoff management via best management practices (BMP) and low impact development (LID) has earned significant recognition owing to positive environmental and ecological impacts. However, due to the complexity of the parameters involved, the estimation of LID efficiency in attenuating the urban surface runoff at the watershed scale is challenging. A planning analysis of employing Green Roofs and Infiltration Trenches as BMPs/LIDs practices for urban surface runoff control is presented in this study. A multi-objective optimization decision-making framework is established by coupling SWMM (Storm Water Management Model) with NSGA-II models to check the performance of BMPs/LIDs concerning the cost-benefit analysis of LID at the watershed scale. Two urbanized areas belonging to Central Delhi in India were used as case studies. The results showed that the SWMM model is useful in simulating optimization problems for managing urban surface runoff. The optimum scenarios efficiently minimized the urban runoff volume while maintaining the BMPs/LIDs implementation costs and size. With BMPs/LIDs implementation, the reduction in runoff volume increases as expenses increase initially; however, there is no noticeable reduction in flood volume after a certain threshold. Contrasted with the haphazard arrangement of BMPs/LIDs, the proposed approach demonstrates 22%-24% runoff reductions for the same expenditures in watershed 1 and 23%-26% in watershed 2. The result of the study provides insights into planning and management of the urban surface runoff control with LID practices. The proposed framework assists the hydrologists in optimum selection and placements of BMPs/LIDs practices to acquire the most extreme ecological advantages with the least expenses.
KW  - Storm water management model
KW  - Genetic algorithm
KW  - NSGA-II
KW  - Best management practice
KW  - Low impact development
KW  - Cost-benefit
Y1  - 2022
U6  - https://doi.org/10.1016/j.jhydrol.2022.127455
SN  - 0022-1694
SN  - 1879-2707
VL  - 606
PB  - Elsevier
CY  - Amsterdam
ER  - 
TY  - JOUR
A1  - Heine, Iris
A1  - Francke, Till
A1  - Rogass, Christian
A1  - Medeiros, Pedro Henrique Augusto
A1  - Bronstert, Axel
A1  - Förster, Saskia
T1  - Monitoring seasonal changes in the water surface areas of reservoirs using TerraSAR-X time series data in semiarid northeastern Brazil
JF  - IEEE journal of selected topics in applied earth observations and remote sensing
N2  - The 933 km(2) Bengue catchment in northeastern Brazil is characterized by distinct rainy and dry seasons. Precipitation is stored in variously sized reservoirs, which is essential for the local population. In this study, we used TerraSAR-X SM(HH) data for an one-year monitoring of seasonal changes in the reservoir areas from July 2011 to July 2012. The monitoring was based on acquisitions in the ascending pass direction, complemented by occasional descending-pass images. To detect water surface areas, a histogram analysis followed by a global threshold classification was performed, and the results were validated using in situ GPS data. Distinguishing between small reservoirs and similar looking dark areas was difficult. Therefore, we tested several approaches for identifying misclassified areas. An analysis of the surface area dynamics of the reservoirs indicated high spatial and temporal heterogeneities and a large decrease in the total water surface area of the reservoirs in the catchment by approximately 30% within one year.
KW  - Image classification
KW  - monitoring
KW  - radar imaging
KW  - remote sensing
KW  - synthetic aperture radar (SAR)
Y1  - 2014
U6  - https://doi.org/10.1109/JSTARS.2014.2323819
SN  - 1939-1404
SN  - 2151-1535
VL  - 7
IS  - 8
SP  - 3190
EP  - 3199
PB  - Inst. of Electr. and Electronics Engineers
CY  - Piscataway
ER  - 
TY  - BOOK
A1  - Bronstert, Axel
A1  - Jürgens, M.
T1  - Modellsystem Hillflow : physikalisch begründete und flächendetalierte Modellierung der Abflußbildung und der Bodenwasserdynamik von ebenen Standorten, Hängen und Kleineinzugsgebieten ; Modelldokumentation und Benutzerhandbuch, Version 1.0
Y1  - 1994
PB  - Inst. für Hydrologie und Wasserwirtschaft, Universität Karlsruhe
CY  - Karlsruhe
ER  - 
TY  - JOUR
A1  - Müller, Eva Nora
A1  - Francke, Till
A1  - Batalla  Villanueva, Ramon J.
A1  - Bronstert, Axel
T1  - Modelling the effects of land-use change on runoff and sediment yield for a meso-scale catchment in the Southern Pyrenees
N2  - The Southern Pre-Pyrenees experienced a substantial land-use change over the second half of the 20th century owing to the reduction of agricultural activities towards the formation of a more natural forest landscape. The land-use change over the last 50 years with subsequent effects on water and sediment export was modelled with the process-based, spatially semi-distributed WASA-SED model for the meso-scale Canalda catchment in Catalonia, Spain. It was forwarded that the model yielded plausible results for runoff and sediment yield dynamics without the need of calibration, although the model failed to reproduce the shape of the hydrograph and the total discharge of several individual rainstorm events, hence the simulation capabilities are not yet considered sufficient for decision-making purposes for land management. As there are only a very limited amount of measured data available on sediment budgets with altered land-use and climate change settings, the WASA-SED model was used to obtain qualitative estimates on the effects of past and future change scenarios to derive a baseline for hypothesis building and future discussion on the evolution of sediment budgets in such a dryland setting. Simulating the effects of the past land-use change, the model scenarios resulted in a decrease of up to 75% of the annual sediment yield. whereas modelled runoff remained almost constant over the last 50 years. The relative importance of environmental change was evaluated by comparing the impact on sediment export of land-use change, that are driven by socio-economic factors, with climate change projections for changes in the rainfall regime. The modelling results suggest that a 20% decrease in annual rainfall results in a decrease in runoff and sediment yield, thus an ecosystem stabilisation in regard to sediment export which can only be achieved by a substantial land-use change equivalent to a complete afforestation. At the same time, a 20% increase in rainfall causes a large export of water and sediment resources out of the catchment, equivalent to an intensive agricultural use of 100% of the catchment area. For wet years, the effects of agricultural intensification are more pronounced, so that in this case the intensive land-use change has a significantly larger impact on sediment generation than climate change. The WASA-SED model proved capable in quantifying the impacts of actual and potential environmental change, but the reliability of the simulation results is still circumscribed by considerable parameterisation and model uncertainties.
Y1  - 2009
UR  - http://www.sciencedirect.com/science/journal/03418162
U6  - https://doi.org/10.1016/j.catena.2009.06.007
SN  - 0341-8162
ER  - 
TY  - JOUR
A1  - Güntner, Andreas
A1  - Bronstert, Axel
T1  - Modelling the effects of climate change on water availability in the semi-arid of North-East Brazil
Y1  - 2001
ER  - 
TY  - JOUR
A1  - Mamede, George Leite
A1  - Guentner, Andreas
A1  - Medeiros, Pedro Henrique Augusto
A1  - de Araujo, Jose Carlos
A1  - Bronstert, Axel
T1  - Modeling the Effect of Multiple Reservoirs on Water and Sediment Dynamics in a Semiarid Catchment in Brazil
JF  - Journal of Hydrologic Engineering
N2  - Taking into account the climatic conditions of the semiarid region of Brazil, with its intermittent rivers and long periods of water scarcity, a dense network of surface reservoirs (on average one dam every 5 km(2)) of very different sizes has been built. The impact of such a network on water and sediment dynamics constitutes a remarkable challenge for hydrologists. The main objective of this work is to present a novel way of simulating water and sediment fluxes through such high-density reservoir networks, which enables the assessment of water and sediment retention in those structures. The new reservoir modeling approach has been coupled with the fully process-oriented and semidistributed hydrological WASA-SED model, which was tailored for semiarid hydroclimatological characteristics. This integrated modeling system was applied to the 933-km(2) Bengue catchment, located in semiarid northeastern Brazil, which has a network of 114 reservoirs with a wide range of surface areas (from 0.003 to 350 ha). The small reservoirs were grouped into size classes according to their storage capacity and a cascade routing scheme was applied to describe the upstream-downstream position of the classes; the large reservoirs were handled explicitly in the reservoir modeling approach. According to the model results, the proposed approach is capable of representing the water and sediment fluxes though the entire reservoir network with reasonable accuracy. In addition, the model shows that the dynamics of water and sediment within the Bengue catchment are strongly impacted by the presence of multiple reservoirs, which are able to retain approximately 21% of the generated runoff and almost 42% of the sediment yield of the catchment for the simulation period, from 2000 to 2012. (C) 2018 American Society of Civil Engineers.
KW  - Reservoir network
KW  - Semiarid catchment
KW  - Sediment retention
KW  - Water storage dynamic
Y1  - 2018
U6  - https://doi.org/10.1061/(ASCE)HE.1943-5584.0001701
SN  - 1084-0699
SN  - 1943-5584
VL  - 23
IS  - 12
PB  - American Society of Civil Engineers
CY  - Reston
ER  - 
TY  - GEN
A1  - Kormann, Christoph
A1  - Bronstert, Axel
A1  - Francke, Till
A1  - Recknagel, Thomas
A1  - Gräff, Thomas
T1  - Model-Based attribution of high-resolution streamflow trends in two alpine basins of Western Austria
N2  - Several trend studies have shown that hydrological conditions are changing considerably in the Alpine region. However, the reasons for these changes are only partially understood and trend analyses alone are not able to shed much light. Hydrological modelling is one possible way to identify the trend drivers, i.e., to attribute the detected streamflow trends, given that the model captures all important processes causing the trends. We modelled the hydrological conditions for two alpine catchments in western Austria (a large, mostly lower-altitude catchment with wide valley plains and a nested high-altitude, glaciated headwater catchment) with the distributed, physically-oriented WaSiM-ETH model, which includes a dynamical glacier module. The model was calibrated in a transient mode, i.e., not only on several standard goodness measures and glacier extents, but also in such a way that the simulated streamflow trends fit with the observed ones during the investigation period 1980 to 2007. With this approach, it was possible to separate streamflow components, identify the trends of flow components, and study their relation to trends in atmospheric variables. In addition to trends in annual averages, highly resolved trends for each Julian day were derived, since they proved powerful in an earlier, data-based attribution study. We were able to show that annual and highly resolved trends can be modelled sufficiently well. The results provide a holistic, year-round picture of the drivers of alpine streamflow changes: Higher-altitude catchments are strongly affected by earlier firn melt and snowmelt in spring and increased ice melt throughout the ablation season. Changes in lower-altitude areas are mostly caused by earlier and lower snowmelt volumes. All highly resolved trends in streamflow and its components show an explicit similarity to the local temperature trends. Finally, results indicate that evapotranspiration has been increasing in the lower altitudes during the study period.
T3  - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 364 
KW  - trend attribution
KW  - trend detection
KW  - climate change
KW  - trend drivers
KW  - hydrological modelling
KW  - alpine catchments
KW  - streamflow
KW  - hydroclimatology
Y1  - 2017
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-400641
ER  - 
TY  - JOUR
A1  - Mtilatila, Lucy Mphatso Ng'ombe
A1  - Bronstert, Axel
A1  - Bürger, Gerd
A1  - Vormoor, Klaus Josef
T1  - Meteorological and hydrological drought assessment in Lake Malawi and Shire River basins (1970-2013)
JF  - Hydrological sciences journal = Journal des sciences hydrologiques
N2  - The study assesses the variability and trends of both meteorological and hydrological droughts from 1970 to 2013 in Lake Malawi and Shire River basins using the standardized precipitation index (SPI) and standardized precipitation and evaporation index (SPEI) for meteorological droughts and the lake level change index (LLCI) for hydrological droughts. Trends and slopes in droughts and drought drivers are estimated using Mann-Kendall test and Sen's slope, respectively. Results suggest that meteorological droughts are increasing due to a decrease in precipitation which is exacerbated by an increase in temperature (potential evapotranspiration). The hydrological system of Lake Malawi seems to have a >24-month memory towards meteorological conditions, since the 36-month SPEI can predict hydrological droughts 10 months in advance. The study has found the critical lake level that would trigger hydrological drought to be 474.1 m a.s.l. The increase in drought is a concern as this will have serious impacts on water resources and hydropower supply in Malawi.
KW  - Lake Malawi basin
KW  - Shire River basin
KW  - meteorological drought
KW  - hydrological drought
KW  - SPEI
KW  - SPI
KW  - trend analysis
Y1  - 2020
U6  - https://doi.org/10.1080/02626667.2020.1837384
SN  - 0262-6667
SN  - 2150-3435
VL  - 65
IS  - 16
SP  - 2750
EP  - 2764
PB  - Routledge, Taylor & Francis Group
CY  - Abingdon
ER  - 
TY  - BOOK
A1  - Bronstert, Axel
A1  - Seiert, S.
A1  - Oberholzer, Gustav
T1  - Maßnahmen der Flurbereinigung und ihre Wirkung auf das Abflußverhalten ländlicher Gebiete : gemeinsamer Bericht des Instituts für Hydrologie und Wasserwirtschaft, Universität Karlsruhe, und des Instituts für Liegenschaftswesen, Planung und Bodenordnung, Universität der Bundeswehr, Neubiberg bei München
T3  - Flurneuordnung und Landentwicklung Baden Württemberg
Y1  - 1993
VL  - 3
PB  - LfU
CY  - Karlsruhe
ER  - 
TY  - JOUR
A1  - Pilz, Tobias
A1  - Francke, Till
A1  - Bronstert, Axel
T1  - lumpR 2.0.0: an R package facilitating landscape discretisation for hillslope-based hydrological models
JF  - Geoscientific model development : an interactive open access journal of the European Geosciences Union
N2  - The characteristics of a landscape pose essential factors for hydrological processes. Therefore, an adequate representation of the landscape of a catchment in hydrological models is vital. However, many of such models exist differing, amongst others, in spatial concept and discretisation. The latter constitutes an essential pre-processing step, for which many different algorithms along with numerous software implementations exist. In that context, existing solutions are often model specific, commercial, or depend on commercial back-end software, and allow only a limited or no workflow automation at all. Consequently, a new package for the scientific software and scripting environment R, called lumpR, was developed. lumpR employs an algorithm for hillslope-based landscape discretisation directed to large-scale application via a hierarchical multi-scale approach. The package addresses existing limitations as it is free and open source, easily extendible to other hydrological models, and the workflow can be fully automated. Moreover, it is user-friendly as the direct coupling to a GIS allows for immediate visual inspection and manual adjustment. Sufficient control is furthermore retained via parameter specification and the option to include expert knowledge. Conversely, completely automatic operation also allows for extensive analysis of aspects related to landscape discretisation. In a case study, the application of the package is presented. A sensitivity analysis of the most important discretisation parameters demonstrates its efficient workflow automation. Considering multiple streamflow metrics, the employed model proved reasonably robust to the discretisation parameters. However, parameters determining the sizes of subbasins and hillslopes proved to be more important than the others, including the number of representative hillslopes, the number of attributes employed for the lumping algorithm, and the number of sub-discretisations of the representative hillslopes.
Y1  - 2017
U6  - https://doi.org/10.5194/gmd-10-3001-2017
SN  - 1991-959X
SN  - 1991-9603
VL  - 10
SP  - 3001
EP  - 3023
PB  - Copernicus
CY  - Göttingen
ER  - 
TY  - JOUR
A1  - Pilz, Tobias
A1  - Francke, Till
A1  - Bronstert, Axel
T1  - lumpR 2.0.0: an R package facilitating landscape discretisation for hillslope-based hydrological models
JF  - Geoscientific model development
N2  - The characteristics of a landscape pose essential factors for hydrological processes. Therefore, an adequate representation of the landscape of a catchment in hydrological models is vital. However, many of such models exist differing, amongst others, in spatial concept and discretisation. The latter constitutes an essential pre-processing step, for which many different algorithms along with numerous software implementations exist. In that context, existing solutions are often model specific, commercial, or depend on commercial back-end software, and allow only a limited or no workflow automation at all.

Consequently, a new package for the scientific software and scripting environment R, called lumpR, was developed. lumpR employs an algorithm for hillslope-based landscape discretisation directed to large-scale application via a hierarchical multi-scale approach. The package addresses existing limitations as it is free and open source, easily extendible to other hydrological models, and the workflow can be fully automated. Moreover, it is user-friendly as the direct coupling to a GIS allows for immediate visual inspection and manual adjustment. Sufficient control is furthermore retained via parameter specification and the option to include expert knowledge. Conversely, completely automatic operation also allows for extensive analysis of aspects related to landscape discretisation.

In a case study, the application of the package is presented. A sensitivity analysis of the most important discretisation parameters demonstrates its efficient workflow automation. Considering multiple streamflow metrics, the employed model proved reasonably robust to the discretisation parameters. However, parameters determining the sizes of subbasins and hillslopes proved to be more important than the others, including the number of representative hillslopes, the number of attributes employed for the lumping algorithm, and the number of sub-discretisations of the representative hillslopes.
Y1  - 2017
U6  - https://doi.org/10.5194/gmd-10-3001-2017
SN  - 1991-959X
SN  - 1991-9603
VL  - 10
SP  - 3001
EP  - 3023
PB  - Copernicus
CY  - Göttingen
ER  - 
TY  - GEN
A1  - Pilz, Tobias
A1  - Francke, Till
A1  - Bronstert, Axel
T1  - lumpR 2.0.0: an R package facilitating landscape discretisation for hillslope-based hydrological models
N2  - The characteristics of a landscape pose essential factors for hydrological processes. Therefore, an adequate representation of the landscape of a catchment in hydrological models is vital. However, many of such models exist differing, amongst others, in spatial concept and discretisation. The latter constitutes an essential pre-processing step, for which many different algorithms along with numerous software implementations exist. In that context, existing solutions are often model specific, commercial, or depend on commercial back-end software, and allow only a limited or no workflow automation at all. 

Consequently, a new package for the scientific software and scripting environment R, called lumpR, was developed. lumpR employs an algorithm for hillslope-based landscape discretisation directed to large-scale application via a hierarchical multi-scale approach. The package addresses existing limitations as it is free and open source, easily extendible to other hydrological models, and the workflow can be fully automated. Moreover, it is user-friendly as the direct coupling to a GIS allows for immediate visual inspection and manual adjustment. Sufficient control is furthermore retained via parameter specification and the option to include expert knowledge. Conversely, completely automatic operation also allows for extensive analysis of aspects related to landscape discretisation. 

In a case study, the application of the package is presented. A sensitivity analysis of the most important discretisation parameters demonstrates its efficient workflow automation. Considering multiple streamflow metrics, the employed model proved reasonably robust to the discretisation parameters. However, parameters determining the sizes of subbasins and hillslopes proved to be more important than the others, including the number of representative hillslopes, the number of attributes employed for the lumping algorithm, and the number of sub-discretisations of the representative hillslopes.
T3  - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 389 
Y1  - 2017
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-402880
ER  - 
TY  - JOUR
A1  - De Araujo, Josè Carlos
A1  - Güntner, Andreas
A1  - Bronstert, Axel
T1  - Loss of reservoir volume by sediment deposition and its impact on water availability in semiarid Brazil
N2  - A methodology is presented to assess the impact of reservoir silting oil water availability for semiarid environments, applied to seven representative watersheds in the state of Ceara, Brazil. Water yield is computed using stochastic modelling for several reliability levels and water yield reduction is quantified for the focus areas. The yield-volume elasticity concept, which indicates the relative yield reduction in terms of relative storage capacity of the reservoirs, is presented and applied. Results chow that storage capacity was reduced by 0.2% year(-1) due to silting, that the risk of water shortage almost doubled in less than 50 years for the most critical reservoir, and that reduction of storage capacity had three times more impact oil yield reduction than the increase in evaporation. Average 90% reliable yield-volume elasticity was 0.8, which means that the global water yield (Q(90)) in Ceara is expected to diminish yearly by 388 L s(-1) due to reservoir silting
Y1  - 2006
UR  - http://www.atypon-link.com/IAHS/loi/hysj
U6  - https://doi.org/10.1623/hysj.51.1.157
SN  - 0262-6667
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  - GEN
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
T2  - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe
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.
T3  - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 1412 
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  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-517763
SN  - 1866-8372
IS  - 4
ER  - 
TY  - JOUR
A1  - Günter, A.
A1  - Bronstert, Axel
T1  - Large-scale hydrological modelling of a semi-arid environment : model development, validation and application
Y1  - 2003
ER  - 
TY  - JOUR
A1  - Niehoff, Daniel
A1  - Bronstert, Axel
T1  - Landnutzung und Hochwasserentstehung : Modellierung anhand dreier mesoskaliger Einzugsgebiete
Y1  - 2002
ER  - 
TY  - JOUR
A1  - Niehoff, Daniel
A1  - Fritsch, Uta
A1  - Bronstert, Axel
T1  - Land-use impacts on storm-runoff generation : scenarios of land-use change and simulation of hydrological response in a meso-scale catchment in SW-Germany
Y1  - 2002
ER  - 
TY  - JOUR
A1  - Fritsch, Uta
A1  - Katzenmaier, Daniel
A1  - Bronstert, Axel
T1  - Land-use and land-cover scenarios for flood risk analysis and river basin management
Y1  - 2000
ER  - 
TY  - JOUR
A1  - Kneis, David
A1  - Knösche, Rüdiger
A1  - Bronstert, Axel
T1  - Ist eine Auswaschung von Nährstoffen aus Flussgewässersedimenten eine realistische Option zur Trophiesenkung?
Y1  - 2004
SN  - 3-937758-18-6
ER  - 
TY  - JOUR
A1  - Kneis, David
A1  - Knösche, Rüdiger
A1  - Bronstert, Axel
T1  - Ist ein Netto-Nährstoffexport aus Flussgewässersedimenten eine realistische Option zur Trophiesenkung?
Y1  - 2004
SN  - 3-937758-18-6
ER  - 
TY  - JOUR
A1  - Miegel, Konrad
A1  - Graeff, Thomas
A1  - Selle, Benny
A1  - Salzmann, Thomas
A1  - Franck, Christian
A1  - Bronstert, Axel
T1  - Investigation of a renatured fen on the Baltic Sea coast of Mecklenburg - Part I: System description and basic hydrological characterisation
JF  - Hydrologie und Wasserbewirtschaftung
KW  - Baltic Sea Coast
KW  - coastal wetland
KW  - drainage of the catchment area
KW  - fens
KW  - groundwater flow
KW  - management effects
KW  - system analysis
KW  - water balance
Y1  - 2016
U6  - https://doi.org/10.5675/HyWa_2016.4_1
SN  - 1439-1783
VL  - 60
SP  - 242
EP  - 258
PB  - Bundesanst. für Gewässerkunde
CY  - Koblenz
ER  - 
TY  - CHAP
A1  - López-Tarazón, José Andrés
A1  - Bronstert, Axel
A1  - Thieken, Annegret
A1  - Petrow, Theresia
ED  - López-Tarazón, José Andrés
ED  - Bronstert, Axel
ED  - Thieken, Annegret
ED  - Petrow, Theresia
T1  - International symposium on the effects of global change on floods, fluvial geomorphology and related hazards in mountainous rivers
T2  - Book of Abstracts
N2  - Both Alpine and Mediterranean areas are considered sensitive to so-called global change, considered as the combination of climate and land use changes. All panels on climate evolution predict future scenarios of increasing frequency and magnitude of floods which are likely to lead to huge geomorphic adjustments of river channels so major metamorphosis of fluvial systems is expected as a result of global change. Such pressures are likely to give rise to major ecological and economic changes and challenges that governments need to address as a matter of priority. Changes in river flow regimes associated with global change are therefore ushering in a new era, where there is a critical need to evaluate hydro-geomorphological hazards from headwaters to lowland areas (flooding can be not just a problem related to being under the water). A key question is how our understanding of these hazards associated with global change can be improved; improvement has to come from integrated research which includes the climatological and physical conditions that could influence the hydrology and sediment generation and hence the conveyance of water and sediments (including the river’s capacity, i.e. amount of sediment, and competence, i.e. channel deformation) and the vulnerabilities and economic repercussions of changing hydrological hazards (including the evaluation of the hydro-geomorphological risks too).

Within this framework, the purpose of this international symposium is to bring together researchers from several disciplines as hydrology, fluvial geomorphology, hydraulic engineering, environmental science, geography, economy (and any other related discipline) to discuss the effects of global change over the river system in relation with floods. The symposium is organized by means of invited talks given by prominent experts, oral lectures, poster sessions and discussion sessions for each individual topic; it will try to improve our understanding of how rivers are likely to evolve as a result of global change and hence address the associated hazards of that fluvial environmental change concerning flooding. 

Four main topics are going to be addressed:

- Modelling global change (i.e. climate and land-use) at relevant spatial (regional, local) and temporal (from the long-term to the single-event) scales.

- Measuring and modelling river floods from the hydrological, sediment transport (both suspended and bedload) and channel morphology points of view at different spatial (from the catchment to the reach) and temporal (from the long-term to the single-event) scales.

- Evaluation and assessment of current and future river flooding hazards and risks in a global change perspective.

- Catchment management to face river floods in a changing world.

We are very pleased to welcome you to Potsdam. We hope you will enjoy your participation at the International Symposium on the Effects of Global Change on Floods, Fluvial Geomorphology and Related Hazards in Mountainous Rivers and have an exciting and profitable experience. Finally, we would like to thank all speakers, participants, supporters, and sponsors for their contributions that for sure will make of this event a very remarkable and fruitful meeting. We acknowledge the valuable support of the European Commission (Marie Curie Intra-European Fellowship, Project ‘‘Floodhazards’’, PIEF-GA-2013-622468, Seventh EU Framework Programme) and the Deutschen Forschungsgemeinschaft (Research Training Group “Natural Hazards and Risks in a Changing World” (NatRiskChange; GRK 2043/1) as the symposium would not have been possible without their help. Without your cooperation, this symposium would not be either possible or successful.
KW  - natural hazards
KW  - mountainous rivers
KW  - floods
KW  - global change
KW  - geomorphology
Y1  - 2017
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-396922
ER  - 
TY  - CHAP
A1  - Bronstert, Axel
T1  - Interdisziplinäres Zentrum für Musterdynamik und angewandte Fernerkundung (IMAF) an der Universität Potsdam : Gegenwart und Zukunft
N2  - Stand des IMAF zu Beginn des Jahres 2006 

Zum 1. April 2005 wurde per Beschluss des Rektorats der Universität Potsdam das Interdisziplinäre Zentrum für Musterdynamik und Angewandte Fernerkundung (IMAF) an der Universität Potsdam eingerichtet. Diesem Beschluss gingen knapp zwei Jahre konzeptionelle, organisatorische und administrative Vorarbeiten voraus. Inzwischen ist das IMAF also offiziell gegründet, der Vorstand wurde „bestellt“ (Prof. M. Mutti. Prof. E. Zehe, Prof. A. Bronstert), der Geschäftsführer bzw. wissenschaftliche Koordinator Dr. M. Kühling arbeitet in dieser Funktion seit Sommer 2005 und seit kurzem ist auch die 1. Version der Homepage des IMAF (http://www.uni-potsdam.de/imaf/) frei geschaltet. Auch die Infrastruktur des IMAF ist in der Entstehungsphase: Büroräume sind versprochen (wenn auch noch nicht bezugsfertig) im Haus 13 auf dem Campus Golm der Universität Potsdam und der 1. erfolgreiche Drittmittelantrag erbrachte 8 leistungsfähige Tischrechner und einen Server für das IMAF aus EU-Mitteln. Wichtiger als die administrativen und organisatorischen Arbeiten sind aber die inhaltlichen Forstschritte. Hier ist die große Resonanz, die die Gründung des IMAF sowohl innerhalb als auch außerhalb der Universität gefunden hat, besonders erfreulich. Über 30 Angehörige des Zentrums sind inzwischen zu verzeichnen und es gibt bereits eine Reihe von wissenschaftlichen Projektinitiativen und Ideen für dieses Zentrum. Neben den wissenschaftlichen Arbeiten am IMAF ist ein zweites Hauptziel für dieses Zentrum die Entwicklung und der Ausbau eines strukturierten Ausbildungsangebotes für Musterdynamik und angewandte Fernerkundung. Dies sollen gleichermaßen Masterstudenten als auch Doktoranden der Universität Potsdam und der mit ihr assoziierten außeruniversitären Institute nutzen. Zudem werden Kurse und Weiterbildungsveranstaltungen mit nationalen und internationalen Experten angestrebt. Neben diesen positiven Entwicklungen gibt es auch (noch ??) über einige Mängel zu berichten: 
Das Sekretariat ist nach wie vor unbesetzt, die Finanzausstattung des Zentrums ist völlig ungenügend und die im Konzept für das Zentrum beantragte Wissenschaftlerstelle für Softwareanwendung ist nicht in Sicht. Für einen Erfolg des Zentrums ist es unbedingt notwendig, dass sich diese Situation deutlich verbessert!! 

Forschungsschwerpunkte des IMAF 

Räumliche Muster und deren Struktur in der Umwelt

Räumliche Muster sind in vielen naturwissenschaftlichen Disziplinen (Hydrologie, Ökologie, Geologie, Biologie, Chemie, Physik) von zentraler Bedeutung. Z.B. bestimmen die räumlichen (und zeitlichen) Muster von Bodeneigenschaften und Vegetation in ihrem Zusammenspiel mit den Mustern von Niederschlag und Strahlungsinput maßgeblich den Wasser- und Stoffhaushalt auf unterschiedlichsten Skalen und führen über Rückkopplung wiederum zu Veränderungen in Klima, Vegetation und Ökosystemen. Vom kleinräumigen Transport von Schadstoffen und von der Hochwasserentstehung bis zur Frage nach den regionalen und globalen Veränderungen von Klima, Vegetation und Landnutzung seien hier nur einige Problemkreise genannt, in denen Muster und Musterdynamik eine zentrale Stellung einnehmen. Darüber hinaus liefert die Betrachtung der zeitlichen Veränderung von räumlichen Mustern, in Ergänzung zur klassischen Erfassung dynamischer Prozesse in Form von Messungen lokaler zeitlicher Änderungen, eine völlig neue Perspektive auf Dynamik und eröffnet damit völlig neue wissenschaftliche Möglichkeiten. Aktuelle und sehr drängende Fragen innerhalb dieses Forschungsschwerpunktes sind unter anderem: 
• Analyse der generelle Raumstruktur von Geodaten (Variabilität, Struktur, Konnektivität); 
• Thematische Verbindungen verschiedener Datenebenen und Möglichkeiten für deren Assimilation; 
• Möglichkeiten und Grenzen des Skalenübergangs zwischen verschiedenen räumlichen Auflösungen und Informationsquellen; 
• Ableitung der zeitlichen Dynamik bzw. Entwicklung von großen flächenhaften Datenfeldern. 

Angewandte Fernerkundung 

Wie keine andere Technik bietet die Fernerkundung in jeglicher Form (unter anderem Satelliten, flugzeuggetragene Sensoren, Wetterradar und auch geophysikalische Methoden) umfangreiche Möglichkeiten, räumliche Muster und deren zeitliche Veränderungen zu erfassen. Allen Methoden der Fernerkundung gemein ist, dass sie nur indirekte Ergebnisse liefern. Das heißt, es besteht nur ein mittelbarer Zusammenhang zwischen dem beobachteten Signal, meist der Reflektivität oder Emissivität elektromagnetischer Strahlung in verschiedenen Spektralbereichen (optisch oder Radar), und der eigentlich interessierenden Größe, wie dem Feuchtezustand der Vegetation, der Bodenfeuchte oder Bodenrauhigkeit, der Niederschlagsintensität, dem Zustand der Schneedecke oder der Ausdehnung eines Oberflächenfilms auf Gewässern. Ein Satellitenbild enthält beispielsweise immer die spektrale Signatur des räumlichen Musters mehrerer der oben genannten Einflussgrößen, was die Extraktion oder Diskriminierung der eigentlich interessierenden Größe erschwert. Dieser „vermischte“ Charakter der Fernerkundungsdaten bietet aber auch immense Chancen. So lassen sich durch geeignete Interpretationsverfahren aus jedem mit hohem finanziellem und technischem Aufwand erstellten Satellitenbild zahlreiche und im Detail völlig unterschiedliche Fragestellungen bearbeiten. Die Extraktion der gewünschten Information aus dem Fernerkundungssignal führt mathematisch gesehen meist auf die Lösung so genannter inverser, schlecht gestellter Probleme. Somit beinhaltet die interdisziplinäre Nutzung von Fernerkundung auch ein hohes methodisches Synergiepotential. Durch die heutigen technischen Möglichkeiten zur Archivierung auch sehr umfangreicher raumbezogener Informationen ist die Bearbeitung zu jedem beliebigen Zeitpunkt nach der Aufnahme möglich – zum Beispiel bis entsprechend lange Zeitreihen und/oder geeignete Interpretationsverfahren zur Verfügung stehen. Tatsächlich dürfte der weitaus größte Teil der raumbezogenen Informationen, die in den bisher erhobenen Fernerkundungsdaten stecken, nur in Ansätzen ausgewertet sein. Einer bereits sehr hoch entwickelten technischen Dimension der Fernerkundung steht ein gewisses Defizit im Umfang ihrer Anwendung in den verschiedenen naturwissenschaftlichen Disziplinen gegenüber. Aktuelle und sehr drängende Fragen innerhalb dieses Forschungsschwerpunktes sind unter anderem: 
• Nutzung der räumlichen und inhaltlichen Breite von Fernerkundungsinformationen; 
• Verbindung mit automatisierten, u.a. geophysikalischen Methoden des „ground-truthings“; 
• Identifizierung der Grenzen bzgl. Repräsentanz der Daten (spektral, raum-zeitliche Auflösung); 
• Verbindung unterschiedlicher Methoden der Fernerkundung und der Geophysik. 

Dieser Beitrag illustriert die o.g. Fragestellungen anhand einiger Darstellungen aus verschiedenen wissenschaftlichen Disziplinen und erläutert 2 Beispiele zu beabsichtigten Forschungsprojekten:
• Erfassung und Bedeutung von Boden-Oberflächeneigenschaften auf die Abflussbildung von Landschaften; 
• Phänomene des Stofftransportes in homogenen vs. heterogenen Böden.
Y1  - 2006
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-7021
N1  - Dokument 1: Foliensatz | Dokument 2: Abstract | Dokumente 3 und 4: Animation  

Interdisziplinäres Zentrum für Musterdynamik und Angewandte Fernerkundung Workshop vom 9. - 10. Februar 2006
ER  - 
TY  - JOUR
A1  - Medeiros, Pedro Henrique Augusto
A1  - de Araujo, Jose Carlos
A1  - Bronstert, Axel
T1  - Interception measurements and assessment of Gash model performance for a tropical semi-arid region
N2  - Semi-arid environments usually face water scarcity and conflicts for its use; therefore a complete understanding of the water balance in these regions is desired. To evaluate interception, measurements of precipitation, throughfall and stemflow were carried out in a Brazilian tropical semi-arid experimental watershed with well preserved Caatinga vegetation. Data analysis indicates that interception losses correspond to 13% of total rainfall, representing an important process in the watershed's water balance, where runoff is only 6% of total precipitation. Gash interception model was applied in the region with good results for long term simulation. Nevertheless, the model produced significant but not systematic errors on a daily basis. This was attributed to its incapability of representing the temporal variation of precipitation during the event, which is a major factor affecting interception. Rainfall intensity was shown to be a good parameter to determine an applicability threshold for Gash model in the study area.
Y1  - 2009
SN  - 0045-6888
ER  - 
TY  - JOUR
A1  - Bronstert, Axel
A1  - Kneis, David
A1  - Bogena, Heye R.
T1  - Interaktionen und Rückkopplungen beim hydrologischen Wandel : Relevanz und Möglichkeiten der Modellierung
Y1  - 2009
SN  - 1439-1783
ER  - 
TY  - JOUR
A1  - Bronstert, Axel
A1  - Kneis, David
A1  - Bogena, Heye R.
T1  - Interactions and feedbacks in hydrological change : relevance and possibilities of modelling
N2  - The hydrological cycle is a dynamic system by its nature, but sometimes accelerated through anthropogenic activity. A "hydrological change" (i.e. a water cycle that is significantly changing over a longer period of time) can be very different in character, depending on the specific natural conditions and the underlying spatial and temporal scales. Such changes may affect the availability and quality of water as essential pre-requisites for human development and ecosystem stability. Hydrological extremes, such as floods and droughts, may also be affected, what is also vitally important, because of their profound economic and societal impacts. Anthropogenically induced hydrological change can be attributed to three main external causes: first, the Earth's climate is changing significantly and thus directly affecting the terrestrial hydro-systems via the exchange of energy and heat. The second major issue is the land cover and its management that has been modified fundamentally by conversion of land for agriculture, forestry, and other purposes such as industrialisation and urbanisation. Finally, water resources are being used more than ever for human development, especially for agriculture, industrial activities, and navigation. If the regional terrestrial hydrological cycle is changing and counter-measures are desirable, it is from a scientific perspective mandatory to understand the extent and nature of such changes, and, especially, to identify their possible anthropogenic origin. There are, however, fundamental gaps in our knowledge, in particular about the role of feedbacks between individual processes and compartments of the hydrological cycle or the relevance of the interactions with other sub-systems of our planet, such as the atmosphere or the vegetation. This paper mentions several examples of hydrological change and discusses their identification, interaction processes, and feedback mechanisms, along with modelling issues. The possibilities and limitations of modelling are demonstrated by means of two studies: one from the river-lake system on the Middle-Havel River and one from the catchment of the Wahnbach Reservoir. The applied model systems comprise a series of consecutively coupled individual models (so-called one-way-coupling). Model systems that are able reflect feedback effects (two-way- coupling) are still in the development stage. It became clear that the applied model systems were able to reproduce the observed dynamics of the hydrological cycle and of selected matter fluxes. However, one has to be aware that the simulated time periods and scenarios represent rather moderately transient conditions, what is the justification why the one-way-coupling seems to be applicable. Furthermore, it was shown that the modelling uncertainty is considerably large. Nevertheless, this uncertainty can be distinguished from effects of changed internal systems dynamics or from changed boundary conditions, what is a basis for the usability of such model systems for prognostic purposes.
Y1  - 2009
SN  - 1439-1783
ER  - 
TY  - JOUR
A1  - Hattermann, Fred
A1  - Krysanova, Valentina
A1  - Habeck, Anja
A1  - Bronstert, Axel
T1  - Integrating wetlands and riparian zones in river basin modelling
JF  - Ecological modelling : international journal on ecological modelling and engineering and systems ecolog
N2  - Wetlands, and in particular riparian wetlands, represent an interface between the catchment area and the aquatic environment. They control the exchange of water and related chemical fluxes from the upper catchment area to surface waters like streams and lakes. Their influence on water and nutrient balances has been investigated mainly at the patch scale. In this study an attempt was made (a) to integrate riparian zones and wetlands into eco-hydrological river basin modelling, and (b) to quantify the impacts of riparian wetland processes on water and nutrient fluxes in a meso-scale catchment located in the northeastern German lowland. The investigation was performed by analysing hydro-chemical field data and applying the eco-hydrological model SWIM (Soil and Water Integrated Model), which was extended to reproduce the relevant water and nutrient flows and retention processes at the catchment scale in general, and in riparian zones and wetlands in particular. The main extensions introduced in the model were: (1) implementation of daily groundwater table dynamics at the hydrotope level, (2) implementation of water and nutrient uptake by plants from groundwater in riparian zones and wetlands, and (3) assessment of nutrient retention in groundwater and interflow. The simulation results indicate that wetlands, though they represent relatively small parts of the total catchment area, may have a significant impact on the overall water and nutrient balances of the catchment. The uncertainty of the simulation results is considerably high, with the main sources of uncertainty being the model parameters representing the geo-hydrology and the input data for land use management. (c) 2006 Elsevier B.V. All rights reserved.
KW  - riparian zones
KW  - wetlands
KW  - water quality
KW  - groundwater dynamics
KW  - nutrient retention
KW  - integrated river basin modelling
Y1  - 2006
U6  - https://doi.org/10.1016/j.ecolmodel.2005.06.012
SN  - 0304-3800
VL  - 199
IS  - 4
SP  - 379
EP  - 392
PB  - Elsevier
CY  - Amsterdam
ER  - 
TY  - JOUR
A1  - Bronstert, Axel
A1  - Krol, Marten S.
A1  - Jaeger, Annekathrin
A1  - Güntner, Andreas
A1  - Hauschild, M.
A1  - Döll, P.
T1  - Integrated modelling of water availability an management in the semi-arid Notheast of Brazil
Y1  - 2000
ER  -