First results of climate change impacts on severe convective storms over Europe

To consider the impact of climate change on severe thunderstorms, it is necessary to assess atmospheric conditions and derived convection-indices like CAPE, CIN and vertical wind shear. Therefore, an algorithm was developed for calculating reversible CAPE and CIN and deep layer wind shear on the basis of 3-dimensional meteorological fields. This is in line with recent investigations by Brooks (2006, 2007) and Trapp et al. (2007) for the United States.

This study is focussed on Central Europe. The current atmospheric state (1958-2001) is evaluated by analysing ERA-40 reanalysis data at full vertical model level resolution. Future trends are derived from simulations of the regional climate model CLM. Verification of the method is attained by comparing the results with sounding-derived parameters and severe storm reports from the European Severe Weather Database (ESWD).

Our study will provide an assessment of the thunderstorm probability for the current atmospheric situation and how this state is going to change due to a climate change scenario. First, some case studies are investigated to determine if severe convection may be found in reanalysis data with horizontal resolution of more than 100 km. After that, there will be a closer look at convection over the last few decades and if changes in quantity or intensity of thunderstorms can already be diagnosed. Finally, there will be first results of how climate change might impact convection over Europe in the future.