Characterizing Uncertainty in a New Patmos-x Merged AVHRR/Hirs Cloud Record

Abstract:

The Pathfinder Atmospheres Extended (PATMOS-x) team produces a global observational cloud record derived from the Advanced Very High Resolution Radiometer (AVHRR) from 1981 present. That record incorporates measurements from fifteen AVHRR sensors including those flown on the NOAA polar orbiting environmental and EUMETSAT Metop satellite series. However, the AVHRR is not the only instrument flown on those satellites; here we incorporate measurements from the High-resolution Infrared Radiation Sounder (HIRS) into the PATMOS-x cloud climate record with the intent of addressing shortcomings in AVHRR spectral information, specifically in those areas where the AVHRR does not produce sufficient radiometric contrast between clouds and surface. Two examples where HIRS is expected to reduce uncertainty the AVHRR record are in Polar Regions and in the detection/analysis of semitransparent ice clouds. Here we will present results from the merged AVHRR/HIRS record with an emphasis on characterizing uncertainty based on sensitivity to viewing geometry, surface type, cloud amount and cloud phase.