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Fri 10 May,17:25 BST (16:25 UTC)
The cloud, radiation and precipitation properties are retrieved from the Spinning Enhanced Visible and Infrared Imager (SEVIRI) on board Meteosat Second Generation (MSG) with the Cloud Physical Properties (CPP) algorithm of KNMI (Roebeling et al., 2006). The MSG-CPP algorithm consists of three steps. The first step is to separate cloud free from cloud contaminated and cloud filled pixels, which is done with a modified version of the cloud detection algorithm developed for the Moderate Resolution Imaging Spectroradiometer (MODIS) (J. Riédi, University of Lille). In the second step the primary cloud properties (Cloud Top Temperature, Cloud Phase, Cloud Optical Thickness and Cloud Particle size) are retrieved in an iterative manner by simultaneously comparing satellite observed reflectances at visible (0.6 um) and near-infrared (1.6 um) wavelengths to Look Up Tables (LUTs) of simulated reflectances of water and ice clouds for given optical thicknesses, particle sizes and surface albedos. These LUTs have been generated with the Doubling Adding KNMI (DAK) radiative transfer model (Stammes, 2001). The third step is to calculate the secondary cloud properties (Cloud Water Path, Cloud Droplet Number Concentration, Cloud Geometrical Thickness, Surface Solar Irradiance, Precipitation occurrence and intensity) for which the retrieval largely relies on the primary cloud properties. The retrievals are limited to satellite and solar viewing zenith angles smaller than 78 degrees.
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Precipitation (3 h)
