CM SAF: Cloud Products
The basic motivation for retrieving cloud climate products from satellite data is that clouds play an important role in the global energy and water cycle. In particular, the presence of clouds dominates the planetary albedo which is a crucial quantity that controls the fraction of the incoming solar radiation that is directly reflected back to space. Consequently, a very important task for climate monitoring missions is to document any changes in the planetary albedo associated with changes in global cloudiness. Important is also to study associated potential feedback links to changes in atmospheric temperatures and water vapour contents.
Furthermore, the fact that different types of clouds have different reflection and absorption characteristics motivates the definition of an additional set of cloud physical properties (such as cloud optical thickness and cloud liquid water path and cloud phase products) as a complement to the traditional cloud amount, cloud type and cloud top products.
The CM SAF cloud products are currently derived from two different passive imaging sensors:
The Advanced Very High Resolution Radiometer (AVHRR) operated onboard the polar National Oceanic and Atmospheric Administration (NOAA) satellites NOAA-15, -16, -17 and -18 and onboard current and upcoming polar Meteorological Operational satellites (MetOp-A, -B, and -C).
The Spinning Enhanced Visible and InfraRed Imager (SEVIRI) operated onboard the geostationary METEOSAT satellites (Meteosat-8, -9).
Further details on the products in general, on retrieval details and physical basis as well as on quality can be found in the Product User Manual CLOUDS
The CM SAF cloud products, i.e., operational monitoring products and produced datasets, should be useful for evaluating cloud simulations from current atmospheric forecasting models as well as from climate models as demonstrated by Karlsson et al. (2008), Roebeling et al. (2009) and Willén (2008). In a longer perspective the retrospectively produced datasets should be the most useful datasets permitting more complete and accurate studies, e.g., of the type published by Zhang et al. (2005).
Kaspar, F., R. Hollmann, M. Lockhoff, K.-G. Karlsson, A. Dybbroe, P. Fuchs, N. Selbach, D. Stein, J. Schulz, 2009: Operational generation of AVHRR-based cloud products for Europe and the Arctic at EUMETSAT’s Satellite Application Facility on Climate Monitoring (CM SAF), Adv. Sci. Res., 3, 45-51.
Karlsson, K.-G., U. Willén, C. Jones and K. Wyser, 2008: Evaluation of regional cloud climate simulations over Scandinavia using a 10-year NOAA Advanced Very High Resolution Radiometer cloud climatology, J. Geophys. Res., 113, D01203, doi:10.1029/2007JD008658.
Roebeling, R.A. and E. van Meijgaard, 2009: Evaluation of the diurnal cycle of model predicted cloud amount and condensed water path over Europe with observations from MSG-SEVIRI, J. Climate., 22, 7, 1749-1766.
Willén, U., 2008: Preliminary use of CM SAF cloud and radiation products for evaluation of regional climate simulations, SMHI Reports Meteorology and Climatology, 131, 48 pp.
Zhang, M.H., et al., 2005: Comparing clouds and their seasonal variations in 10 atmospheric general circulation models with satellite measurements, J. Geophys. Res., 110, D15S02, doi:10.1029/2004JD005021.R
RH / Jan2014