*Note: This dataset version has been superseded by a newer version. It is highly recommended that users access the current version. Users should only use this version for special cases, such as reproducing studies that used this version.* The Pathfinder Atmospheres - Extended (PATMOS-x) Reflectance data contain derived atmospheric variables from the Advanced Very High Resolution Radiometer (AVHRR) Global Area Coverage (GAC) data observed from three decades of the NOAA Polar-orbiting Operational Environmental Satellite (POES) series. PATMOS-x data consists of twice daily fields from AVHRR/1, AVHRR/2 and AVHRR/3 GAC data from 1978 to 2009. The radiometric products are on a consistent grid spacing which allows for a thorough diagnosis of time-series information. There is no averaging of multiple pixels as each data point in a file represents a single GAC pixel-level value. Variables are produced on a 0.1 degree Latitude/Longitude grid with dimensions of 3601 by 1801. Each daily PATMOS-x product file provides data derived from one NOAA POES satellite in either an ascending or descending orbital node. Spatial overlap of orbital coverage occurs at most latitudes. Highlights of the product include improved accuracy in geolocation and improved reflectance calibrations of the AVHRR data. Reflectance from the visible and Near Infrared (VIS/NIR) channels 1, 2 and 3a on AVHRR constitute this fundamental Climate Data Record (CDR).