Background

Since 2005, ECMWF has generated model-simulated satellite images from the 00 UTC and 12 UTC  cycles of the operational HRES forecast out to five days for all operational geostationary satellites (i.e., MET-7, MET-10, MTSAT-2, GOES-13 and GOES-15). The simulated images are archived in MARS as GRIB edition 1 files and have been presented on the ECMWF website as PostScript image files. The forecast-generated satellite images have been based on the resolution of the HRES global model with 3-hourly output from T+0 to T+48 and 6-hourly output to step=120.

Up to and including IFS cycle 41r1, the satellite images in both the window and water vapour (WV) channels were simulated over each of the 5 geostationary satellite’s disk. Brightness temperatures were calculated using the same radiative transfer algorithm (RTTOV-11) as in the operational data assimilation and using the relevant atmospheric model profiles (temperature, specific humidity, ozone mass mixing ratio, cloud cover, specific cloud liquid water content, specific cloud ice water content, specific rain water content, specific snow water content) and the relevant surface parameters (skin temperature, 10m u and v wind components, 2m temperature and 2m dewpoint temperature, volumetric soil water layer 1, convective available potential energy).

Errors in simulated satellite images can derive from errors in the NWP parameters, on which the simulation is based, the resolution of the model and RTTOV model performance.

Updates to the simulated satellite images at IFS cycle 41r2

• The updated simulated satellite images introduced at IFS cycle 41r2 are global whereas the previous image showed only the disk visible to the satellite.
• No longer geostationary but includes latitudes greater than 60 degrees north and south so covers polar regions
• Assumes nadir view for all points in the fields so the effect of looking slantwise through the atmosphere is thus neglected.  Consequently the atmosphere appears less opaque than with the previous simulated images and so lower lying clouds and other features are better presented.
• Available in dissemination
• Sub-areas supported
• Only images corresponding to the Meteosat-10 channels 5, 6 and 9 are available. 
• The images corresponding to the GOES and HIMWARI satellites that were available at IFS cycle 41r1 are discontinued.

Availability of the simulated satellite images in dissemination

Availability of the simulated satellite images in MARS