Calibration of Historical Visible Geostationary Data for ISCCP and Other Applications

The reprocessing of the International Satellite Cloud Climatology Project (ISCCP) to the new generation H-series product is underway at the NOAA National Centers for Environmental Information (NCEI). The ISCCP H-series product relies on the higher resolution (10 km 3 hourly) ISCCP B1U data compared to the predecessor D-series product that employed the reduced resolution B3 data set. Independent assessments of the calibration of the infrared (IR) and visible (VIS) channels of the geostationary satellites have been made through comparing with the High Resolution Infrared Radiation Sounder (HIRS) brightness temperatures for the IR, and the Advanced Very High Resolution Radiometer (AVHRR) reflectance data from the AVHRR Pathfinder Atmospheres-Extended (PATMOS-x) dataset for VIS. In ISCCP H-series production, the polar orbiters are monitored (and corrected) as the calibration standard for geostationary VIS and IR channels. The present study describes the H-series calibration procedure and reports results of cross-calibration with the HIRS in the IR and PATMOS-x CDR product in the VIS and comparison with the ISCCP calibration for the extended period beyond the base period (1983-2009).