Clemens Simmer received the B.S. and Ph.D. degrees in meteorology from the University of Cologne, Cologne, Germany, in 1981 and 1983, respectively. Since 1996, he has been with the Meteorological Institute, University of Bonn, Bonn, Germany, where he is currently the Head of the working group on remote sensing and mesoscale modeling. He is also an expert in coupled modeling of the regional Earth system, model evaluation, data assimilation, satellite and ground-based remote sensing, and regional climate analysis. He is a member of the Center for High-Performance Computing of Terrestrial Systems HPSC TerrSys (www.hpsc-terrsys.de), which helps geoscientists of the Geoverbund ABC/J (alliance of the geosciences within the universities RWTH Aachen, Bonn and Cologne and the Forschungszentrum Jülich) to efficiently use the JSC supercomputers for geoscientific modeling. In the field of ground-based remote sensing, he concentrates on microwave-based active and passive methods with a current focus on precipitation and cloud processes in cooperation with the Jülich Observatory for Cloud Cartography - Core Facility (JOYCE-CF). His efforts in regional climate analysis concentrated in the past on the evaluation of extremes and trends from German and European precipitation observation stations and moved recently to dynamic downscaling of global climate runs.