Global SST is measured twice-daily with an Advanced Very High Resolution Radiometer (AVHRR) as part of the NOAA/NASA Pathfinder Program.  This instrument has been making measurements of emitted and reflected radiance since 1981 on board the NOAA -7, -9, -11, 12, and -14 polar-orbiting satellites.  The nadir spatial resolution is 1.1 km.   The data presented here have a spatial resolution of ~9 km (equal-angle grid).

As part of the NOAA/NASA Pathfinder Program, the SST values are calculated from the measured radiances as follows:  First, atmospheric effects are removed from the measurements after calibration of the sensors.  The resulting radiances (measured at 5 wavebands in the visible and infrared) are then converted to units of temperature using the Planck function.  The estimated temperatures are then calibrated with in-situ SST measurements.  Further details regarding the AVHRR data sets and their processing are available from the AVHRR Ocean Pathfinder SST site.

Website by Jasmine S. Bartlett, Oregon State University.