Performance evaluation of high-resolution regional climate simulations in the alpine space and analysis of extreme events

Abstract

This study aimed to assess the capabilities of high-resolution simulations in reproducing the main features of the climate in the complex topography region of the Alps for the period 1971–2000. This is to provide a reliable tool for impact studies on local scale. Two simulations, driven by ERA-40 Reanalysis, have been carried out, respectively, at spatial resolutions of 0.125° and 0.0715° with the regional climate model COSMO-CLM. The model response has been analyzed in terms of 2 m temperature and precipitation, and comparisons with available observations have been carried out. A number of climate indices have also been analyzed, widely adopted to monitor changes in extreme climate events. Finally, the effects of increasing spatial resolution have also been investigated. The model at high spatial resolution (0.0715°) provides a satisfactory representation of temperature. The simulated precipitation patterns are also improved due to the high model resolution that allows reproducing localized precipitation phenomena with a medium-high error, especially where summer thunderstorms over the complex topography of the Alpine region occurs.