Comparison of Various Sea Surface Temperature Fields

Abstract

Different estimates of the monthly mean sea surface temperature (SST) fields are intercompared. Fields derived from ship data alone differ substantially in high SST gradient regions and in areas of low data density. These differences exhibit seasonal and interannual variations which are spatially correlated. The large bias and variability preclude interchangeable use of different SST products derived from ships alone.

The difference between SST fields from ships and similar fields derived from a blend of satellite and ship data show many of the characteristics noted above, north of 30° N. However, inclusion of satellite data results in a warm bias that is substantially larger than that found between ship-only products. The difference fields south of 30° N are of order one standard deviation or more with the blended product again generally being warmer. The difference fields are regional in nature at all latitudes. Thus global or zonal averaging of the fields, as is done in many papers comparing satellite SST’s with other estimates, could lead to erroneous conclusions regarding the degree of comparability between the fields.