OISST

OISST is the NOAA Daily Optimum Interpolation Sea Surface Temperature analysis, a gap-free global SST product on a 0.25 degree grid from September 1981 to present, version 2.1. It blends AVHRR satellite radiances with ship, buoy, and Argo in-situ data, bias-adjusting satellite and ship values to the buoy reference, then fills gaps by optimum interpolation. The daily, complete fields make it a standard baseline for SST anomalies, ENSO monitoring, marine-heatwave detection, and as a lower boundary condition for atmospheric models.