Atmospheric rivers are long narrow bands of large integrated water vapor transport in the troposphere. At land fall they are usually associated with extreme conditions in terms of wind and precipitation. In recent years there has been a growing interest in atmospheric rivers, concerning their regional impacts on water availability, the modulation by climate variability and their representation in weather and forecast models. Airsea interaction processes are major modulators by two aspects of describing and understanding atmospheric rivers, (i) in the source area over the large oceans and by (ii) coastal processes at land fall. How atmospheric rivers interact with surface conditions and coastal features is to a large extent unknown. By using measurements taken by the applicant and collaborators specific air-sea and air-sea land interaction features of importance for atmospheric rivers, the source area and at land fall will be investigated. By developing parameterizations and implementing them in regional (WRF-Wavewatch-NEMO) and global (EC-Earth) coupled modelling systems, predictive and climatological description of atmospheric rivers will be significantly expanded. The ultimate goal of the project is to quantify the importance of air-sea interaction on atmospheric rivers for better prediction of extreme events in the coastal zone.