USING THE HIRS DATA TO RECORD MORE THAN THREE DECADES OF GLOBAL CLOUD AND MOISTURE PROPERTIES

The High resolution Infrared Radiation Sounder (HIRS) has been flown on sixteen satellites from TIROS-N through NOAA-19 and METOP-A and -B forming more than a 35-year record. Sensor to sensor radiance calibration differences have been mitigated using high spectral resolution infrared data from the Infrared Atmospheric Sounding Interferometer (IASI) as a reference to adjust spectral response functions in the recent HIRS data (NOAA-15 through NOAA-19). Satellite Nadir Overpasses (SNOs) have been used to intercalibrate the HIRS sensors before IASI (NOAA-6 through NOAA-14). Thirty five year trends in detection of high clouds and estimation of total column precipitable water vapor (TPW) have been reprocessed and studied. Results indicate that (1) hemispheric (NH and SH) seasonal high clouds are exactly out of phase, with seasonal high cloud fluctuation greater in SH than NH, (2) TPW is highest in tropics and the seasonal TPW cycle is strongest in northern mid-latitudes and weakest in the tropics, (3) hemispheric seasonal TPW are exactly out of phase, with the seasonal TPW fluctuation greater in NH than SH, and (4) hemispheric seasonal TPW and high clouds are exactly in phase. Continuation of the cloud and moisture property determinations with IASI and CrIS is being explored.