Reprocessing the AVHRR and HIRS Records to Generate a New PATMOS-x Cloud Climatology

Over thirty years of AVHRR and HIRS measurements are reprocessed to create a new version of the PATMOS-x cloud climatology that incorporates HIRS spectral channels into existing AVHRR retrievals. Spectral limitations of the AVHRR make cloud detection challenging in low sun and nighttime conditions, especially in polar and mountainous regions. Here we show how the use of HIRS IR water vapor and CO2 absorption bands can improve the detection of clouds in these problematic areas. This presentation will focus on those areas where improvements in cloud detection are found, and conversely areas where improvements were expected but not found or where cloud detection suffered. Additionally we will focus on cloud record stability, and attempt to assess in what ways, if any, the AVHRR+HIRS version of PATMOS-x is an improvement for climate applications.