Global and regional Pathfinder SST fields: characterization and validation

As part of the National Aeronautic and Space Administration's and the National Oceanic and Atmospheric Administration's Pathfinder program in the United States, all of the five-channel Advanced Very High Resolution Radiometer (AVHRR) Global Area Coverage (GAC) data for the globe are being reprocessed to a consistent set of sea surface temperature (SST) fields. These fields, at a spatial resolution of 9.28 km and a temporal resolution of 12 hours, are available to the oceanographic community at no cost. Following a description of the Pathfinder project the authors' effort to validate the resulting global SST fields is presented. This effort evaluates climatologies of SST obtained from the global Pathfinder fields through a statistical comparison with the uppermost temperature value for hydrographic data in the 1994 World Ocean Atlas (WOA94) data set. The performance of the Pathfinder AVHRR climatologies is compared with that of previous climatologies and is shown to be superior to these in representing the mean SST state.