Intercalibration of the Infrared Window and Water Vapor Channels on Operational Geostationary Environmental Satellites Using a Single Polar-Orbiting Satellite

The Cooperative Institute for Meteorological Satellite Studies (CIMSS) has been intercalibrating radiometers on five geostationary satellites (GOES-8, -10, Meteosat-5, 7, and GMS-5) using a single polar-orbiting or low-earth orbiting satellite [NOAA-14 High -Resolution Infrared Radiation Sounder (HIRS) and Advanced Very High Resolution Radiometer (AVHRR)] as a reference on a routine basis using temporally and spatially collocated measurements. This is being done for the 11-(mu)m infrared window (IRW) channels as well as the 6.7-(mu)m water vapor (WV) channels. IRW results between AVHRR or HIRS and all five geostationary instruments show relatively small differences, with all geostationary instruments vicariously comparing to within 0.6 K. The WV results between HIRS and all five geostationary instruments show larger differences, with geostationary instruments separating into two groups: GOES-8, -10, and GMS-5 comparing within 1 K; Meteosat-5 and -7 comparing within 0.1 K; and the two groups comparing within 2.7 K.