Future changes in extreme precipitation in the Rhine basin based on global and regional climate model simulations

S C Van Pelt,B J J M Van Den Hurk,J J Beersma,T A Buishand,P Kabat

doi:10.5194/hess-16-4517-2012

Abstract

Abstract. Probability estimates of the future change of extreme precipitation events are usually based on a limited number of available global climate model (GCM) or regional climate model (RCM) simulations. Since floods are related to heavy precipitation events, this restricts the assessment of flood risks. In this study a relatively simple method has been developed to get a better description of the range of changes in extreme precipitation events. Five bias-corrected RCM simulations of the 1961–2100 climate for a single greenhouse gas emission scenario (A1B SRES) were available for the Rhine basin. To increase the size of this five-member RCM ensemble, 13 additional GCM simulations were analysed. The climate responses of the GCMs are used to modify an observed (1961–1995) precipitation time series with an advanced delta change approach. Changes in the temporal means and variability are taken into account. It is found that the range of future change of extreme precipitation across the five-member RCM ensemble is similar to results from the 13-member GCM ensemble. For the RCM ensemble, the time series modification procedure also results in a similar climate response compared to the signal deduced from the direct model simulations. The changes from the individual RCM simulations, however, systematically differ from those of the driving GCMs, especially for long return periods.

Highlights

Heavy precipitation events are of importance since they are a major cause of floods, which can have large impacts on society
It is found that the range of future change of extreme precipitation across the five-member regional climate model (RCM) ensemble is similar to results from the 13-member global climate model (GCM) ensemble
This study explores the possibility to combine the future changes in extreme precipitation from an RCM ensemble with the future changes in a GCM ensemble

Summary

Introduction

Heavy precipitation events are of importance since they are a major cause of floods, which can have large impacts on society. Based on a wide range of observational and global climate model (GCM) and regional climate model (RCM) studies, changes in greenhouse gas concentrations are expected to affect the frequency and magnitude of extreme precipitation. These studies show an intensification of precipitation extremes over most of Europe (Beniston et al, 2007; Buonomo et al, 2007; Fowler and Ekstrom, 2009; Frei et al, 2006; Hanel and Buishand, 2011; Kyselyand Beranova, 2009; Kyselyet al., 2011; Nikulin et al, 2011). Credible high-resolution climate scenarios for impact studies require an ensemble of RCM simulations driven by multiple GCMs (Fowler et al, 2007; Bernstein et al, 2007) Such ensembles should represent the full range of natural variability and model uncertainty. They are assembled on an opportunity basis, and often the size of the ensembles is restricted by limited resources (Kendon et al, 2010)

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Results

Conclusion