The following pages show EUMETSAT's inter-calibration results applied to different pairs of satellite instruments. The basic concept is that observations from a reference instrument with well-known calibration characteristics are compared with collocated observations from another instrument to derive calibration corrections for the latter. This ensures consistency between the products of the different instruments.

Satellite inter-calibration is beneficial for two reasons:

• Inter-calibration can identify problems and increase the confidence in the operational calibration of individual satellites. Hence, inter-calibration can serve as a monitoring tool for the operational calibration;
• Inter-calibration can provide the basis for a normalised calibration, which is a prerequisite for the derivation of global products from different satellites. Normalisation is to be done with respect to a particular satellite, where a polar orbiter is best suited due to its global coverage.

GSICS Prototype

The GSICS Meteosat IR Inter-Calibration page shows the prototype results of the inter-comparison of equivalent infrared channels of geostationary Meteosat imagers and the polar-orbiting IASI sounder from collocated observations. The results, using the inter-calibration algorithm, can also be downloaded as Statistical Data, in NETCDF Format, from EUMETSAT's GSICS Data and Product Server. The results for 2007 were analysed by Hewison and König, 2008 (See Inter-Calibration of Meteosat Imagers and IASI from the Proceedings of the EUMETSAT Satellite Conference, Darmstadt, Germany, September 2008).

Other

The shows the calibration coefficients for infrared and water vapour channels of the imagers derived by comparison with collocated observations from the HIRS sounders on NOAA polar-orbiting satellites. The method is descibed in more detail . The calibration coefficients derived from this method are compared with those used operationally.