HR: 1355h
AN: GC13B-02    [Abstracts]
TI: Precipitation Extremes as a Function of Resolution in the PRUDENCE Regional Climate Model Setup
AU: * Christensen, O B
EM: obc@dmi.dk
AF: Danish Met. Institute, Lyngbyvej 100, Copenhagen, DK-2100, Denmark
AB: The regional climate model HIRHAM has been used in resolutions of 50km, 25 km and 12km to perform 30-year long time slice climate change simulations in the setup of the European Union project PRUDENCE (http://prudence.dmi.dk). This project encompassed a systematic investigation of 10 different European regional models, which in one set of simulations were driven by one common set of boundary conditions. These came from the global atmospheric model HadAM3H and covered the time slices 1961-1990 and 2071-2100 according to the SRES scenario A2 for an area covering Europe and surrounding areas. This systematic regional model intercomparison has been continued in the ongoing ENSEMBLES project (http://www.ensembles-eu.org). A comparison of the HIRHAM results with observations shows that the higher-resolution simulation is more realistic. This applies to orographic rainfall and land-sea contrasts, but also to extremes, even when data are aggregated to the coarser-resolution grid. Climate change is shown to affect extreme precipitation to a higher degree than mean values for Europe in accordance with the conclusions reached in the PRUDENCE project; during summer, the average precipitation in Central and Southern Europe decreases by up to around 40%, but extreme precipitation is nevertheless generally increasing. It was a general feature of PRUDENCE simulations that summer extremes had a more positive climate change signal than the summer average, even though the absolute sign of the change in extremes varied. The conclusion of positive changes in extremes is very clear in the high-resolution simulation. Results from a pilot study of hourly precipitation shows that similar conclusions hold as in the case of daily precipitation.
DE: 1854 Precipitation (3354)
DE: 3355 Regional modeling
DE: 9335 Europe
SC: Global Environmental Change [GC]
MN: 2007 Fall Meeting