Lidar remote sounding of cirrus clouds and comparison of simulated fluxes with surface and METEOSAT observations

At the top of the atmosphere, the differences between METEOSAT measurements and model are in fair agreement for longwave fluxes (up to 50 Wm−2). However, unexpected high differences are found for shortwave fluxes (up to 144 Wm−2) due to cirrus clouds heterogeneities and uncertainties in their microphysical properties and especially the occurrence of high reflectivity due to horizontally oriented ice crystals at the cloud top, which are not taken into account by the Model presently.