An investigation of the difference between skin and bulk sea surface temperatures in the Southern Ocean between Australia and Antarctica

Data were collected on board the RSV Aurora Australis in order to investigate the difference between the skin sea surface temperahlre (SST) and the bulk SST in the Southern Ocean. Bulk SST is the traditional sea surface temperature measured in situ by ship and buoy based thermometers and is representative of the upper few metres of the ocean. Thermal infrared radiometers will measure the skin SST, the temperahlre of the upper few microns less than 0.05 mm (Maul 1985), of the ocean surface. Previous research has shown that given typical conditions over tropical and temperate oceans, the skin SST is 0.1 - 0.5 °C cooler on average than the bulk SST (Robinson et al. 1984). This temperature difference ( ll.T = skin SST - bulk SST) is due mainly to the presence of a thermal boundary layer (less than 1 mm thick) which is a consequence of evaporation from the sea surface and the molecular conductive processes of heat transfer across the air-sea interface (Robinson et al. 1984; Hepplewhite 1989).