Temperature response of a salinity stratified ocean to air-sea heat fluxes

The strong freshwater layering in the upper 50m of the Bay of Bengal is thought to impact the air-sea exchange of heat between the ocean and atmosphere. When the ocean cools, convective mixing is contained within the fresh layers, even as they become cooler than subsurface waters, the salinity gradients still sustain density stratification, limiting the depth of heat exchange to a shallow layer. This also leads to partial compensation at fronts: sharp lateral gradients are slumped into shallow stratification beneath the fresh side, which cools more than the denser salty side. During times of strong shortwave heating the water column is stabilised unrelated to the salinity structure. However if winds stir the ocean, heat is mixed over less depth in shallow fresh layers and their sea surface temperature increases more rapidly. The diurnal cycle can therefore lead to a greater response in fresh layers than in salty layers.