Monday, 12 January 2004
Reduced horizontal sea surface temperature gradients under conditions of clear sky and weak winds
Hall AB
Consideration of the dependence of the various components of sea surface heat flux on the sea surface temperature itself leads to an explanation for observed reduction in the horizontal temperature gradients in the uppermost layer of the ocean (of the order of 0.5 to a few meters depth). This phenomenon masks horizontal temperature gradients within the mixed layer by a near surface uniform layer of warm water. The warm layer camouflage of horizontal temperature gradients may be of concern for fisheries, acoustic transmissions, and hurricane development among many and various uses of SST data. We examine conditions in mid latitudes (the German Bight) and in the subtropics and tropics, the Florida coast, and Gulf of Mexico. It is universally found that if there is net heating with the solar input being stronger than the evaporative, sensible, and radiative heat losses summed together, the originally warmer water experiences less net heating than the colder water, leading to weakening of the horizontal SST gradients.
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