Clouds play a central role in the Earth's atmosphere by modulating the radiation budget and generating precipitation. Observations of clouds are important for a variety of applications, such as climate and weather model evaluation and nowcasting. My research focuses on the retrieval and validation of cloud properties from satellite instruments, mainly passive imagers such as SEVIRI on Meteosat and AVHRR on NOAA and Metop satellites. Apart from cloud properties like optical thickness and liquid/ice water path, we derive precipitation and surface incoming radiation.
CM SAF (EUMETSAT) generates high-quality climate data records of variables describing the energy and water cycle. Two main data records of cloud properties, as well as, radiation and surface albedo, have recently been produced: CLARA-A2 (global, AVHRR-based, starting in 1982) and CLAAS-2 (Europe/Africa/Atlantic, SEVIRI-based, starting in 2004). Cloud_CCI (ESA) focuses on the generation of consistent multi-instrument global cloud data records. KNMI contributes with the development of a simulator and comparisons of the dataset with regional climate model simulations. HAIC (EU) is concerned with the detection of high concentrations of high-altitude ice crystals for aviation safety. We work on detection schemes based on geostationary imagery. MSG-CPP (KNMI) is a near-real time retrieval and visualization system of SEVIRI observations. These data are used for nowcasting and model evaluation.