NOAA Climate Data Record (CDR) of AVHRR Polar Pathfinder Extended (APP-X) Cryosphere, Version 2

NOAA Climate Data Record (CDR) of the eXtended AVHRR Polar Pathfinder (APP-X) cryosphere contains 19 geophysical variables over the Arctic and Antarctic for the period 1982 - present. All of them have undergone various degrees of validation, though not all are considered CDR quality. The variables are (those considered by the developers to be CDR-quality are identified with an asterisk): Surface temperature, all-sky, snow, ice, and land Surface albedo, all-sky Sea ice thickness Surface type Cloud mask Cloud particle thermodynamic phase Cloud optical depth Cloud particle effective radius Cloud temperature Cloud pressure Cloud type Downwelling shortwave radiation at the surface Downwelling longwave radiation at the surface Upwelling shortwave radiation at the surface Upwelling longwave radiation at the surface Upwelling shortwave radiation at the TOA Upwelling longwave radiation at the TOA Shortwave cloud radiative forcing at the surface Longwave cloud radiative forcing at the surface APP-x data products are mapped to a 25 km EASE grid at two local solar times: 04:00 and 14:00 for the Arctic, and 02:00 and 14:00 for the Antarctica. Using local solar time rather than standard UTC times provides better information on diurnal differences at all locations. The latest update to version 2 includes folding in the APP FCDR updates (updated calibration coefficients for AVHRR GAC visible channels) along with improved algorithms for the land mask, cloud mask, and ice thickness.