Response in extremes of daily precipitation and wind from a downscaled multi-model ensemble of anthropogenic global climate change scenarios

Abstract

Time-slices of eight global climate model (GCM) response simulations of the IPCC IS92a, CMIP2, SRES A2, B2 and A1B greenhouse gas scenarios have been downscaled using the HIRHAM atmospheric regional climate model (RCM). The area covers Central and Northern Europe, adjacent sea-areas and Greenland. The GCM data were provided from the Max Planck Institute, Germany (MPI), the Hadley Centre, U.K. (HC), the Bjerknes Centre, Norway (BCCR) and University of Oslo, Norway (UiO). The resulting ensemble covers a range of future climate realizations from different global models, different greenhouse gas scenarios and natural climate variability. In order to present trends in statistical parameters including extreme events and their return periods, the downscaled response data are combined as an ensemble of equally valid possible realizations. The combined statistics is obtained after adjustments accounting for (i) different set-ups of the respective GCMs in producing the control climate and (ii) the variable range of time between the control and scenario periods. We find that annual extreme events of daily precipitation and wind speed in the control climate become more frequent in the scenario period over large areas in Northern Europe. The variability in the regional result appears sensitive to the phase of the Scandinavian pattern.