Heat budget of the East Antarctic lower atmosphere derived from a regional atmospheric climate model

[1] The heat budget of the lower East Antarctic atmosphere is calculated using output from a regional atmospheric climate model. The climatology of this model compares well with observations, although the surface energy budget shows an underestimation of the downwelling longwave radiation and an overestimation of the sensible heat flux. The winter atmospheric boundary layer over Antarctica is characterized by a strong surface inversion, due to longwave cooling of the surface. The longwave radiation loss is balanced by heat extracted from the atmosphere by turbulent mixing, which in turn is compensated by large-scale horizontal and vertical heat advection. Above the boundary layer, net longwave cooling is balanced by subsidence. In the coastal margin, latent heat release from condensation is a significant heat budget component. In summer, the surface is near radiative balance, resulting in a weak surface inversion. As a result, cooling by turbulent mixing and heating by advection in the atmospheric boundary layer are largely reduced. Absorption of shortwave radiation is a small heating source throughout the atmosphere, reducing the importance of advection above the boundary layer. Net longwave cooling and heating by condensation remain unchanged compared to winter.