IMPROVED SEA-SURFACE TEMPERATURE-MEASUREMENTS FROM SPACE

We investigate ATSR's skin SST precision by comparing all the availabl e high resolution (1km) ATSR data coincident with global drifting buoy records for the months of February and March 1992. Comparisons are ma de at two spatial levels: using spatially averaged ATSR data, and at t he 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 channe ls. The mean bulk-skin temperature bias is 0.45K (night) and 0.13K (da y). The precision is greater: (i) at night than during the day, (ii) w hen 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 inheren t variability of the skin effect.