Erik Kjellström (Sweden) 1; Geert Lenderink (Netherlands) 2; Petter Lind (Sweden) 1; Danijel Belusic (Sweden) 1
1 - Swedish Meteorological and Hydrological Institute; 2 - KNMI
We investigate how a very high resolution (≤3 km grid spacing) convection permitting regional climate model (CPRCM) can be used to provide information about precipitation and precipitation extremes for a number of regions covering Europe in today’s climate and in a climate representing a warmer world. Simulations cover ten months from the last two decades representing summer conditions with large amounts of convective precipitation. In addition, a surrogate climate change experiment was made in which the boundary conditions for the RCMs were changed to represent a two-degree warming.
The model evaluation indicates that the models are able to represent climatological features for the selected 10 months in a good way. Notable results show that the CPRCM produces more fine-scale simulations and also simulates stronger high-intensity precipitation extremes than the coarser scale RCMs. The surrogate climate change experiments indicate that precipitation and precipitation extremes increase in a two-degree warmer climate. Changes in precipitation mostly follow the Clausius-Clapeyron relationship with about a 6–7% increase in precipitation per degree of temperature increase. An exception to this relates to high-intensity precipitation events where high-end (above 90%) percentiles (based on hourly data) show stronger increase up to twice the Clausius-Clapeyron relation. The results also show benefit of the CPRCM over the RCMs related to local (CPRCM scale) maximum hourly precipitation compared to mean (RCM scale). The experimental design of our surrogate climate simulations, with a relatively large number of events sampled through a number of month-long simulations, shows some benefits in interpreting ‘Future Weather’ simulations in terms of climate change compared to studies based on single events.