Heat waves over Central Europe in ALADIN-Climate/CZ regional climate model.: evaluation and future projections

We evaluated a simulation of Central European heat waves and analysed possible changes of their characteristics in the future climate using the ALADIN-Climate/CZ regional climate model with 25 km horizontal grid spacing. Lateral boundary conditions were provided by the ARPEGE global climate model, using historical forcing and the SRES A1B scenario. Observed data were taken from the E-OBS gridded data set. Heat waves were evaluated over 1970-1999 and changes in their characteristics were assessed for 2020-2049. Their definition is based on exceedance of the 90th percentile of summer daily maximum temperature calculated separately for modelled and observed data. ALADIN-Climate/CZ simulates characteristics for the recent climate quite well, especially the overall severity of heat waves. In contrast, temperature amplitude was considerably overestimated. This model projects an increase in overall heat wave severity by a factor of 2 to 3 in the future climate, primarily driven by an increasing number of events. The study shows that ALADIN-Climate/CZ is generally capable of simulating Central European heat waves, which gives more credibility to model projections of future heat waves.