The NOAA/NESDIS Office of Research and Applications (ORA) has embarked on a pilot data stewardship project aimed at improving the data record from the Advanced Very High Resolution Radiometer (AVHRR). One part of this larger project includes the generation of a new cloud climatology from the Extended AVHRR Pathfinder Atmospheres (PATMOS-x) data set. Included within the PATMOS-x data-stream is a full suite of cloud products including various cloud amounts. This paper compares the PATMOS-x cloud amount time series for all July data (1982-2004) to the cloud amount time series from the International Satellite Cloud Climatology Project (ISCCP) and University of Wisconsin High Resolution Infrared Sounder (UW/HIRS) data sets. The results indicate that the large intersatellite discontinuities in the total amount seen in the original PATMOS are reduced in PATMOS-x. The total cloud for July time series from PATMOS-x, UW/HIRS and PATMOS show little trend over the period studied but that ISCCP time series does indicate a continuous downward trend When comparing the time series of high cloud amount, it was that PATMOS-x shows no significant trend in high cloud from 20S to 20N.
Validation of the CLAVR-x cloud detection algorithm over ocean is presented in this paper. CLAVR-x is the latest AVHRR processor developed at the NOAA/NESDIS Office of Research and Applications, with much improved cloud detection algorithm than its CLAVR predecessors. As our first validation study, we have selected sea surface temperature obtained from the NOAA-16 AVHRR GAC data for July 2001. The SST data was matched-up with global buoy data, which was assumed to be ground truth. Both fixed and drifting buoys were considered. This analysis indicates that the CLAVR-x cloud masking allows for generation of sea surface temperature values that are in good agreement with in situ buoys.