Impact of Climate Change on the Hydrological Regimes in Bavaria

Abstract

This study assesses the change of the seasonal runoff characteristics in 98 catchments in central Europe between the reference period of 1981–2010, and in the near future (2011–2040), mid future (2041–2070) and far future (2071–2099). Therefore, a large ensemble of 50 hydrological simulations featuring the model WaSiM-ETH driven by a 50-member ensemble of the Canadian Regional Climate Model, version 5 (CRCM5) under the emission scenario Representative Concentration Pathway (RCP 8.5) is analyzed. A hierarchical cluster analysis is applied to group the runoff characteristics into six flow regime classes. In the study area, (glacio-)nival, nival (transition), nivo-pluvial and three different pluvial classes are identified. We find that the characteristics of all six regime groups are severely affected by climate change in terms of the amplitude and timing of the monthly peaks and sinks. According to our simulations, the monthly peak of nival regimes will occur earlier in the season and the relative importance of rainfall increases towards the future. Pluvial regimes will become less balanced with higher normalized monthly discharge during January to March and a strong decrease during May to October. In comparison to the reference period, 8% of catchments will shift to another regime class until 2011–2040, whereas until 2041–2070 and 2071–2099, 23% and 43% will shift to another class, respectively.

Challenges in modeling and predicting floods and droughts: A review

“…Ensembles of climate simulations are used to enhance the sample size of forcings and obtain a better understanding of uncertainties. Examples of such ensemble‐based simulation approaches include Single‐Model Initial‐condition Large Ensembles (Poschlod, Willkofer, & Ludwig, 2020; van der Wiel, Wanders, Selten, & Bierkens, 2019) and the UNprecedented Simulated Extreme ENsemble approach, which increases the sample size by pooling ensemble members and lead times from seasonal prediction systems (Kelder et al, 2020; Thompson et al, 2017). Event identification : Unifying drought and flood definitions is possible if focusing on below‐ and above‐threshold events for droughts and floods, respectively.…”

Large ensemble climate model simulations: introduction, overview, and future prospects for utilising multiple types of large ensemble

“…They can also be used to look at local changes in internal variability (e.g. Leduc et al, 2019) and projected changes in the signal-to-noise ratio of both the mean and importantly extremes (Aalbers et al, 2018;Poschlod et al, 2020b). With the availability of SMILEs, impact studies, e.g.…”

“…With the availability of SMILEs, impact studies, e.g. in hydrology, can assess new ways of analysing the impacts of climate change on hydrological processes, reaching from water balance studies and flow regime changes (Poschlod et al, 2020a) to extreme events, such as floods (Willkofer and Ludwig, 2020). In order to deal with the challenges of dynamically altered extreme events under climate change, often compound events, SMILEs can introduce the concept of analysing the relevance of climate variability by means of spatially explicit and process-based models, assessing the non-linear response to multiple meteorological drivers, such as in alpine snow cover dynamics (Willibald et al, 2020) and (managed) land surface responses (Zscheischler et al, 2018).…”

Environmental Viability Analysis of Connected European Inland–Marine Waterways and Their Services in View of Climate Change

“…The comparison of inland waterways in terms of geographic and climatic conditions, water resources management practices, navigability, environmental problems, hydrological regimes, and socio-economic conditions is particularly justified in view of climate change. Climate change is expected to bring about significant changes in the field of surface water management since it also changes hydrological conditions [27,28]. Most models anticipate a significant increase in annual mean temperature, which is expected to be greatest during the summer season.…”