Transitioning Historical Satellite Cloud Climate Products to New Sensors while Maintaining Climate-Quality Consistency

The Pathfinder Atmospheres Extended (PATMOS-x) climate data record is a satellite-based global record of atmospheric cloud properties extending over four decades. PATMOS-x is derived from the AVHRR imager flown on the NOAA POES and EUMETSAT MetOp series, but with the launch of MetOp-C in 2018 came the last of the AVHRR equipped satellites. To continue PATMOS-x and other long-term AVHRR-based records a transition to the next generation of polar imagers is needed. To this end the PATMOS-x team has begun processing VIIRS products for continuation of the record. In addition, the latest version of PATMOS-x incorporates observations from the HIRS sounder, also flown on the POES and MetOp satellites. Like the AVHRR, the HIRS is no longer flown on modern satellites, so IASI and CrIS are being evaluated as replacements. This presentation will discuss the lessons learned from the process of producing climate-quality consistency between cloud records from different imager/sounder pairings (e.g. AVHRR/HIRS, AVHRR/IASI, VIIRS/CrIS). Attention will be paid to how instrument-level differences translate downstream to level2 products and how these differences were addressed.