Simulation of spatiotemporal dynamics of water fluxes in Germany under climate change

Abstract

Abstract:In most of Europe, an increase in average annual surface temperature of 0Ð8°C is observed, and a further increase is projected. Precipitation tends to increase in northern Europe and decrease in southern Europe, with variable trends in central Europe. The climate scenarios for Germany suggest an increase in precipitation in western Germany and a decrease in eastern Germany, and a shift of precipitation from summer to winter. When investigating the effects of climate change, impacts on water resources are among the main concerns. In this study, the first German-wide impact assessment of water fluxes dynamics under climate change is presented in a spatially and temporally distributed manner using the state-of-the-art regional climate model, Statistical Regional (STAR) model and the semi-distributed process-based eco-hydrological model, soil and water integrated model (SWIM). All large river basins in Germany (lower Rhine, upper Danube, Elbe, Weser and Ems) are included. A special focus of the study was on data availability, homogeneity of data sets, related uncertainty propagation in the model results and scenario-related uncertainty. After the model calibration and validation (efficiency from 0Ð6 to 0Ð9 in 80% of cases) the water flow components were simulated at the hydrotope level, and the spatial distributions were compared with those in the Hydrological Atlas of Germany. The actual evapotransipration is likely to increase in most parts of Germany, while total runoff generation may decrease in south and east regions. The results for the second scenario period 2051-2060 show that water discharge in all six rivers would be 8-30% lower in summer and autumn compared with the reference period, and the strongest decline is expected for the Saale, Danube and Neckar. Higher winter flow is expected in all of these rivers, and the increase is most significant for the Ems (about 18%). However, the uncertainty of impacts, especially in winter and for high water flows, remains high.

Climate change adaptation and sustainable regional development: a case study for the Federal State of Brandenburg, Germany

“…Many recent investigations (e.g. Huang et al 2010; submitted) highlighted the challenges that result from shifts in precipitation patterns and snow regime, changes in seasonal water availability and water quality, rise of sea level, and increase in the frequency and/or intensity of river floods and droughts, all coupled with the rise in mean surface temperature. The State of Brandenburg has been struck by several severe river floods in the last 15 years, and the scenario projections show that the intensity of floods will most likely increase under climate change (Hattermann et al 2011).…”

Effect of modelling scale on the assessment of climate change impact on river runoff

“…Kingston and Taylor 2010, Parajuli 2010, Zhang et al 2011, including related models, such as SWIM (Krysanova et al 1998). These assessments are typically done for small (49.6 km 2 ; Zhang et al 2011), medium (2098 km 2 ; Kingston and Taylor 2010) and large catchments (13 000-147 423 km 2 ; Huang et al 2010). For water resources management, climate change impact assessments made at the medium and large scale are the most desired.…”

Coastal Lagoons in Europe: Integrated Water Resource Strategies

“…Therefore, the outputs of various RCMs for the same region under the same driving conditions (CO 2 emission, socio-economic pathway) may differ significantly. However, the sensitivity of water balance to relatively small changes in climate parameters may be quite substantial (Lehner et al 2005;Hattermann et al 2008;Huang et al 2010), and the simulated impacts are usually presented with the uncertainty bounds. Often in the past, when the effects of climate change on water budget and/or water quality were studied, only one regional climate model was used as a driver of the hydrological model.…”

“…A set of climate model outputs was used to drive a hydrological model for impact assessment in the German project KLIWAS for the Rhine, Elbe and Danube basins, applying ensembles of regional climate scenarios for the A1B emission scenario Klein et al 2011). A similar approach was used to study potential impacts of climate change on seasonal water discharge and extreme events in terms of floods and low flow for all rivers in Germany (Huang et al 2010(Huang et al , 2012(Huang et al , 2013. The results from a new generation of hydrological climate change impact studies, combining new methods for downscaling and bias correction of climate projections with new methods for large-scale hydrological modelling are presented by Arheimer et al (2013).…”