REMOTE SENSING OF WATER AND ICE CLOUDS FROM MSG/SEVIRI

Clouds and their interaction with radiation are still one of the main uncertainties in our understanding of present and the prediction of future climate. MSG/SEVIRI - with its unique combination of time and spatial resolution and spectral information - has the potential of contributing significantly to the reduction of this gap. We have developed a new water and ice cloud detection and microphysical properties remote sensing algorithm. Cloud detection and classification is based on a prototype version of the EUMETSAT Scenes Analysis scheme, with a particular emphasis on the detection of thin ice clouds. Cloud microphysical properties are retrieved using tabulated forward calculations by a detailed radiative transfer code, libRadtran, which takes into account cloud phase, microphysical properties as well as a complete description of the background atmosphere and surface. Particular attention is given to the treatment of inhomogeneous clouds where we aim at combining the spectral information of the low-resolution channels with the higher spatial resolution of the HRV channel, in order to directly consider sub-pixel cloud inhomogeneity in the retrieval to reduce potential biases.