Die chronologische Liste zeigt aktuelle Veröffentlichungen aus dem Forschungsbetrieb der Hochschule Weihenstephan-Triesdorf. Zuständig ist das Zentrum für Forschung und Wissenstransfer (ZFW).
How to construct recursive digital filters for baseflow separation (2005) Hydrological Processes 19 (2), S. 507-515.
DOI: 10.1002/hyp.5675
There is widespread agreement that good correspondence of measured and calculated streamflow at the catchment outlet is not a sufficient criterion for the validity of a physically based hydrologic model, but that additional knowledge concerning catchment-internal processes is needed (e.g. Beven, 1989). Yet, for many catchments such information is not available and the model’s performance can only be assessed by comparing calculated and measured streamflow. However, the information provided by a hydrograph is not limited to the absolute height of the runoff. For example, a separation of the hydrograph allows for identification of runoff components originating from different compartments of the considered system, and responding differently delayed and smoothed to rainfall events. An example of the potential benefit of this information for modelverification has been given by Eckhardt et al. (2002).
Prof. Dr. Klaus Eckhardt
Abbildung heterogener Bodeninformation in verteilten hydrologischen Modellen (2004) Beitrag zum Forum für Hydrologie und Wasserbewirtschaftung 05.04 , S. 101-104.
Prof. Dr. Klaus Eckhardt,
Klaus Bigalke
Berechtigungen: Peer Reviewed
Comparison of two model systems for the calculation of the solar irradiance on shaded, arbitrarily orientated surfaces (2004) Meteorologische Zeitschrift 13 (5), S. 369-372.
DOI: 10.1127/0941-2948/2004/0013-0369
In its guideline 3789, part 2, the VDI (Verein Deutscher Ingenieure – German Association of Engineers) presents methods that allow the calculation of hourly values of the global irradiance on arbitrarily orientated surfaces. In the present study, these approaches are compared to an alternative combination of previously published models for different partial stages of the simulation that have been implemented in a program called METSUN. It is shown that measurements of the global radiation and of its components can be better reproduced with METSUN than with the approaches of the VDI guideline. Furthermore, the alternative modelcombination is more flexibly usable. The VDI guideline imperatively requires observations of the degree of cloud cover. With METSUN, however, also sources of information that provide values of the global irradiance on an unshaded horizontal plane can be used as starting point of the calculations, for example measurements of the global radiation at a nearby meteorological station. It is shown that this can increase the reliability of the results.In der VDI-Richtlinie 3789, Blatt 2, werden Verfahren zur Berechnung stündlicher Werte der Globalstrahlung auf beliebig orientierte Oberflächen vorgestellt. In der vorliegenden Studie werden diese Ansätze mit einer alternativen Kombination existierender Modelle für Teilschritte der Simulation verglichen, die in einem Programm namens METSUN implementiert wurden. Es wird gezeigt, dass sich Messwerte der Globalstrahlung und ihrer Komponenten mit METSUN besser reproduzieren lassen als mit den Ansätzen der VDI-Richtlinie.Die alternative Modellkombination ist außerdem flexibler verwendbar. Die VDI-Richtlinie setzt zwingend das Vorliegen von Beobachtungswerten des Bedeckungsgrades voraus. Mit METSUN dagegen können auch Informationsquellen genutzt werden, die Werte für die Globalstrahlung auf eine unbeschattete horizontale Fläche liefern, beispielsweise Messungen der Globalstrahlung an einer nahe gelegenen meteorologischen Station. Es wird gezeigt, dass sich die Genauigkeit der Simulationsergebnisse dadurch erhöhen kann.
Prof. Dr. Klaus Eckhardt,
Uwe Ulbrich
Berechtigungen: Peer Reviewed
Potential impacts of climate change on groundwater recharge and streamflow in a central European low mountain range (2003) Journal of Hydrology 284 (1-4), S. 244-252.
DOI: 10.1016/j.jhydrol.2003.08.005
General Circulation Models simulate significant changes of temperature and precipitation over Europe as part of the anthropogenic climate change. In this study, the impacts of climate change on groundwater recharge and streamflow in a central European low mountain range catchment are investigated using a conceptual eco-hydrologic model, a revised version of the Soil and Water Assessment Tool (SWAT). To improve the reliability of our simulations, we compile plant physiological studies concerning the influence of elevated ambient CO2 concentrations on stomatal conductance and leaf area. Using this information to parameterise the model, we evaluate the impacts of two climate change scenarios, which represent a wide range of assumptions concerning future greenhouse gas emissions and climate sensitivity. The resulting effects on mean annual groundwater recharge and streamflow are small, as increased atmospheric CO2 levels reduce stomatal conductance thus counteracting increasing potential evapotranspiration induced by the temperature rise and decreasing precipitation. There are, however, more pronounced changes associated with the mean annual cycle of groundwater recharge and streamflow. Our results imply that due to the warming a smaller proportion of the winter precipitation will fall as snow. The spring snowmelt peak therefore is reduced while the flood risk in winter will probably increase. In summer, mean monthly groundwater recharge and streamflow are reduced by up to 50% potentially leading to problems concerning water quality, groundwater withdrawals and hydropower generation.
Lutz Breuer,
Prof. Dr. Klaus Eckhardt,
Hans-Georg Frede
Berechtigungen: Peer Reviewed
Plant parameter values for models in temperate climates (2003) Ecological Modelling 169 (2-3), S. 237-293.
DOI: 10.1016/S0304-3800(03)00274-6
Johan Alexander Huisman,
Lutz Breuer,
Prof. Dr. Klaus Eckhardt,
Hans-Georg Frede
Spatial Consistency of Automatically Calibrated SWAT Simulations in the Dill Catchment and Three of its Sub-Catchments (2003) Proceedings of the 2nd International SWAT Conference vom 01.-04. Juli in Bari (Italien), Texas Water Resources Institute (TWRI) Technical Report 266 , S. 168-173.
Prof. Dr. Klaus Eckhardt,
Lutz Breuer,
Hans-Georg Frede
Berechtigungen: Peer Reviewed
Parameter uncertainty and the significance of simulated land use change effects (2003) Journal of Hydrology 273 (1-4), S. 164-176.
DOI: 10.1016/S0022-1694(02)00395-5
Uncertainty in parameters characterising different land covers leads to uncertainty in model predictions of land use change effects. In this study, a new approach is presented which allows a model to be assessed to see whether it is suitable for investigating land use change scenarios in the sense that different land covers can be significantly distinguished in their effects on model output. It consists of the following steps: (a) The uncertainty in land cover-dependent parameters is quantified. (b) The model of an artificial catchment with representative characteristics and uniform land cover is established. (c) Using this artificial catchment, Monte Carlo simulations are carried out to determine the uncertainty in the model response to different land covers. (d) By comparing the results for two covers, respectively, a dimensionless test statistic, the distinction level, is calculated. The distinction level is a normalised probability that two independent realisations of land covers which are parameterised within their range of natural uncertainty will yield distinct model responses. If the distinction level is greater than or equal to 90%, the land covers are assumed to have a significantly different effect on the model output. An example of the application of the new method is provided using the eco-hydrologic model SWAT-G. The land covers forest, pasture and arable land can be significantly distinguished by their long-term means of surface runoff, groundwater recharge and streamflow. The minimum proportion of the catchment area on which land cover must change in order to obtain significantly distinct model responses depends on the land covers involved and the considered hydrologic variable. In the case of a change between pasture and forest and with regard to average streamflow, this minimum proportion amounts to about 25%, a value that compares well with the results of paired catchment studies.
Lutz Breuer,
M. Bach,
Hans-Georg Frede,
Prof. Dr. Klaus Eckhardt
Konzeption eines integrierten Modellsystems als Spatial Decision Support System für Wassereinzugsgebiete (2003) KA Korrespondenz Abwasser, Abfall (2), S. 189-194.
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