ocean heat budget
In the Antarctic zone south of 54°S, the surface mixed layer is heated by around 1.6°C between December and March. The surface heat flux is on average 100 W/m² which would heat the surface mixed layer more than observed. A heat budget has been performed on the surface mixed layer in the Antarctic Zone, including horizontal advection terms calculated from data and models, and the vertical entrainment and diffusion from models only (Chaigneau et al., 2004). The results show that geostrophic and Ekman advection act to cool the Antarctic Zone by an average of 0.3°C/month, by transporting cool, low salinity water from the southwest across the SURVOSTRAL line. Vertical diffusion and entrainment reduces the surface mixed layer temperature by another 0.2°C/month.
At other latitudes, the variability in thermal content is dominated by the meridional variations in the frontal positions; here the seasonal signal is hard to determine.