Inferring Global Cloud Cover Properties And Trends From Thirty Years Of HIRS Data

The frequency of occurrence of upper tropospheric clouds has been extracted from NOAA/HIRS polar orbiting satellite data from 1979 onwards using CO2 slicing to infer cloud amount and height. Algorithm adjustments for instrument noise, sensor to sensor differences, viewing angle, spectral response shifts, calculated versus measured radiance biases, changing CO2 and O3 amounts, and investigator error have been studied. High spectral resolution infrared data from AIRS has been used to adjust spectral response functions in the recent HIRS data. CALIPSO measurements are being used to verify the adjustments in the CO2 slicing algorithm. Some lessons learned are being documented and the next steps are to overlay the HIRS cloud properties on those derived form the AVHRR-based PATMOS-x output. This poster will touch on all of these topics.