Atmospheric correction and determination of sea surface temperature in midlatitudes from NOAA-AVHRR data

In this paper we derive and validate a split-window algorithm for retrieving the sea surface temperature (SST) in midlatitude atmospheric conditions. First we have analyzed the physical fundamentals of the split-window approach. Then an algorithm has been theoretically derived by means of statistical regression over satellite measurement simulations, and it has been tuned for real NOAA-AVHRR measurements using in situ and coincident satellite data. The accuracy achieved for SST is 0.5 K, which is the limit accuracy that can be obtained from AVHRR measurements over midlatitudes. On the other side, we have proposed a strategy for applying the split-window algorithm without significantly increasing the noise level. This has the advantage of enhancing real thermal gradients and removing ficticious gradients introduced by the atmosphere.