Master thesis defence by Uta Klönne

Future projections of European heat waves based on an ensemble of regional climate models participating in EURO-CORDEX

Extreme weather or climate events can have potentially adverse impacts on societies. The summer heat wave of 2003 in Central Europe for instance led to increases in human morbidity and mortality. Understanding these events, their driving forces and possible changes over the past decades is therefore crucial, as is exploring their future frequency and intensity under continued anthropogenic climate change.

In this thesis future heat wave occurrence and maximum length are studied using an ensemble of regional climate model (RCM) simulations. RCMs have shown to represent heat waves well as smaller-scale processes relevant for their development can be resolved. The RCMs used here take part in the European branch of the regional climate downscaling project CORDEX.

The thesis takes its starting point in evaluating the ability of RCMs driven with reanalysis boundary forcings to reproduce past observed European heat waves. Then, projected changes in the two heat wave indices for the late 21st century under the highest climate change scenario RCP8.5 are examined. Also, the distributions of daily maximum temperature of the control and scenario periods are analysed, for the entire European study region and four subregions with different climatic characteristics. The thesis also discusses the sources of uncertainties associated with regional climate change projections.

Cathrine Fox Maule, Danish Meteorological Institute
Peter Ditlevsen, Centre for Ice and Climate, NBI, University of Copenhagen