1Deutscher Wetterdienst (DWD), Frankfurter Straße 135, 63004 Offenbach, Germany
2Royal Meteorological Institute of Belgium (RMI), Ringlaan 3 Avenue Circulaire, 1180 Brussels, Belgium
3Koninklijk Nederlands Meteorologisch Instituut (KNMI), Wilhelminalaan 10 3732 GK De Bilt, The Netherlands
4MeteoSchweiz, P.O. Box 514, 8044 Zürich, Switzerland
5Swedish Meteorological and Hydrological Institute (SMHI), Folkborgsvägen 1, 601 76 Norrköping, Sweden
6Finnish Meteorological Institute (FMI), P.O. Box 503, 00101 Helsinki, Finland
Abstract. The Satellite Application Facility on Climate Monitoring (CM-SAF) aims at the provision of satellite-derived geophysical parameter data sets suitable for climate monitoring. CM-SAF provides climatologies for Essential Climate Variables (ECV), as required by the Global Climate Observing System implementation plan in support of the UNFCCC. Several cloud parameters, surface albedo, radiation fluxes at the top of the atmosphere and at the surface as well as atmospheric temperature and humidity products form a sound basis for climate monitoring of the atmosphere. The products are categorized in monitoring data sets obtained in near real time and data sets based on carefully intercalibrated radiances. The CM-SAF products are derived from several instruments on-board operational satellites in geostationary and polar orbit as the Meteosat and NOAA satellites, respectively. The existing data sets will be continued using data from the instruments on-board the new joint NOAA/EUMETSAT Meteorological Operational Polar satellite. The products have mostly been validated against several ground-based data sets both in situ and remotely sensed. The accomplished accuracy for products derived in near real time is sufficient to monitor variability on diurnal and seasonal scales. The demands on accuracy increase the longer the considered time scale is. Thus, interannual variability or trends can only be assessed if the sensor data are corrected for jumps created by instrument changes on successive satellites and more subtle effects like instrument and orbit drift and also changes to the spectral response function of an instrument. Thus, a central goal of the recently started Continuous Development and Operations Phase of the CM-SAF (2007–2012) is to further improve all CM-SAF data products to a quality level that allows for studies of interannual variability.