IMPROVED SEA-SURFACE TEMPERATURE-MEASUREMENTS FROM SPACE

We investigate ATSR's skin SST precision by comparing all the available high resolution (1km) ATSR data coincident with global drifting buoy records for the months of February and March 1992. Comparisons are made at two spatial levels: using spatially averaged ATSR data, and at the fun (1km) resolution. SSTs in each case are derived using both the standard algorithm and one using the 3.7 mu m and 11 mu m nadir channels. The mean bulk-skin temperature bias is 0.45K (night) and 0.13K (day). The precision is greater: (i) at night than during the day, (ii) when 12 mu m noise contamination in the standard SST product is removed, (iii) when using a 1/2 degrees subset for which a corresponding 1km match-up exists. Our highest precision subset has an r.m.s. scatter of just 0.25K and must approach the geophysical limit set by the inherent variability of the skin effect.