Extending the HIRS data record from NOAA's low earth orbit (LEO) satellites

The High-resolution Infrared Radiation Sounder (HIRS) instrument flown on the NOAA series of Polar orbiters has provided long time series of climate quality data records of atmospheric temperature, moisture, ozone, cloud climatology, upper tropospheric humidity, outgoing longwave radiation and other geophysical parameters spanning a period of over 40 years (1978 – present, although experiencing degradation recently). NOAA/NCEI efforts to extend the time series of HIRS-like data records into the future through employing the newer generation Instrument Infrared Atmospheric Sounding Interferometer (IASI) aboard the Meteorological Operational satellite programme (METOP) has been successful. The present study describes ongoing efforts to further extend the HIRS-like data time series employing the NOAA’s LEO satellites series comprising the Suomi National Polar-orbiting Partnership (SUOMI-NPP), and Joint Polar Satellite System (JPSS-1 and JPSS-2) which carry the Cross-track Infrared Sounder (CrIS) instrument on board. IASI and CrIS radiances convolved with the HIRS spectral response functions are refered to as IHIRS and CHIRS respectively here. IHIRS and CHIRS data are calibrated to the same reference to form a homogenized time series for extending the long-term HIRS records. Unlike the IASI and HIRS pairs on the same platform (METOP-2), calibration of CrIS-simulated HIRS poses some challenges. These include colocation of CrIS with C-IHIRS pixels and limb-correction methodology. The presentation will discuss efforts to overcome these challenges to produce a calibrated CrIS-simulated HIRS data similar to the calibrated IASI-simulated HIRS data (C-IHIRS).