An investigation of the relationship between the skin temperature of the sea surface and the temperature of the dynamically significant surface layer.

摘要

The surface temperature of the earth's oceans is a dynamic component of interest to oceanographers, meteorologists, climatologists, biologists and naval forces. The upper 10 metres of the sea surface is thermally stratified from the molecular boundary at the air-sea interface down to the top of the isothermal mixed layer. A variety of instruments are available to observe sea surface temperature (SST), each unique in its depth of measurement within the surface layer. Satellite infra-red (IR) sensors have provided end users with a continuous supply of near-real time, accurate, global images of the upper 10 mum, or skin layer. The Argo array of autonomous profiling floats also provides global coverage in near real-time, however, its near surface measurements are representative of foundation SST (SSTfnd), a depth free of any diurnal warming. The temperature of the skin layer is generally a few tenths to several degrees cooler than SSTfnd, several metres below. Although IR sensors and Argo floats observe different physical temperature regimes, these layers are connected through turbulent mixing processes. For IR estimates of skin temperature to be useful to end users interested in SST fnd, the mixing processes and subsequent temperature gradient must be understood and accounted for. Three MODIS SST data sets: 11 mum day, 11 mum night and 4 mum night, were compared to co-located Argo near-surface observations in two regions of the Pacific northeast from 2003 to 2010. Their respective mean foundation-skin residuals and standard deviations were determined and compared to the results of similar studies. Initial regional results indicated that a temperature offset exists that is geographically and seasonally variable, the results from each of the three comparisons are comparable to previous studies and the variability is within the +/-0.4°C accuracy limits imposed by the scientific community.