The geostationary orbit (GEO) satellites rotates the Earth at an altitude of 35,786 km (22,236 mi) above the Equator. They appear stationary with respect a fixed point on the Earth. The stationary orbits and the large field of regard of the instruments provide great opportunity to measure the earth targets with the low-earth orbits (LEO) satellite instruments at the almost same time and viewing geometry condition. Comparison of the geographical, temporal and viewing-aligned collocated scenes at similar spectral wavelength channels allows to evaluate the calibration difference between the GEO and LEO instruments. In current GSICS GEO-LEO inter-calibration, two well-calibrated hyper-spectral LEO satellite instruments, Atmospheric Infrared Sounder (AIRS) on-board at Aqua satellite and Infrared Atmospheric Sounding Interferometer (IASI) on-board at Metop-A satellites are used to evaluate radiometric calibration accuracy and provide the corrections for the broad-band infrared (IR) channels of GEO satellite data.
GSICS correction products for the GOES satellite based on GOES vs. IASI night-time collocation data can be downloaded at [[http://gsics.nesdis.noaa.gov/thredds/nesdisResults.html[NOAA GSICS server]].
Monitoring the baseline algorithm products for the other GEO satellite is available at GSICS GCC website
The GSICS GOES-IASI inter-calibration product uncertainty evaluation is also available