Assessment of future flood hazard in Europe using a large ensemble of bias-corrected regional climate simulations

• Published in: Journal of Geophysical Research: Atmospheres Vol. 117; no. D17
• Main Authors: Rojas, R., Feyen, L., Bianchi, A., Dosio, A.
• Format: Journal Article
• Language: English
• Published: Washington, DC Blackwell Publishing Ltd 16-09-2012; American Geophysical Union
• Subjects: bias correction; Climate; Climate change; climate change impacts; climate uncertainty; Earth sciences; Earth, ocean, space; Exact sciences and technology; Extreme weather; Flood hazards; flood uncertainty; Floods; Geophysics; high-resolution climate simulation; Hydrologic models; Hydrology; large-scale hydrological modeling; River flow; Snowmelt; Stream flow; Uncertainty; Sweden; Europe; Ireland; Poland; Southern Europe; Italy; United Kingdom; Central Europe; Scandinavia; Germany; Western Europe; ANE, Baltic Sea; British Isles; experimental studies; floods; projects; Bias; simulation; greenhouse gas; maximum likelihood; discharge; temperature; Natural hazards; uncertainties; climate change; Baltic countries; rainfall; atmospheric precipitation; Regional scope; inundations; Climate models; cartography; climate; extreme value; Snow melt; signal-to-noise ratio; Pan; reduction; streamflow
• ISSN: 0148-0227; 2169-897X; 2156-2202; 2169-8996
• DOI: 10.1029/2012JD017461

We assess future flood hazard in view of climate change at pan‐European scale using a large ensemble of climate projections. The ensemble consists of simulations from 12 climate experiments conducted within the ENSEMBLES project, forced by the SRES A1B emission scenario for the period 1961–2100. Prior to driving the hydrological model LISFLOOD, climate simulations are corrected for bias in precipitation and temperature using a Quantile Mapping (QM) method. For time slices of 30 years, a Gumbel distribution is fitted by the maximum likelihood method through the simulated annual maximum discharges. Changes in extreme river flows, here exemplified by the 100‐year discharge (Q100), are then analyzed with respect to a control period (1961–1990). We assess the uncertainty arising from using alternative climate experiments to force LISFLOOD and from the fitting of extreme value distributions. Results show large discrepancies in the magnitude of change in Q100among the hydrological simulations for different climate experiments, with some regions even showing an opposite signal of change. Due to the low signal‐to‐noise ratio in some areas the projected changes showed not all to be statistically significant. Despite this, western Europe, the British Isles and northern Italy show a robust increase in future flood hazard, mainly due to a pronounced increase in extreme rainfall. A decrease inQ100, on the other hand, is projected in eastern Germany, Poland, southern Sweden and, to a lesser extent, the Baltic countries. In these areas, the signal is dominated by the strong reduction in snowmelt induced floods, which offsets the increase in average and extreme precipitation.
Key Points
Future flood hazard using high‐resolution bias‐corrected climate simulations
Large uncertainties bound to projected changes of future flood hazard
Increasing trend in future flood hazard, shifting to rainfall‐dominated floods