Ekman dynamics of the atmospheric boundary layer over the Antarctic Plateau in summer

Abstract

The dynamics of the polar atmospheric boundary layer and its impact on the global atmospheric circulation are important issues in earth science research. We used GPS sounding data collected during summer 2012-2013 at Kunlun Station, Antarctica, to analyze dynamic characteristics of the atmospheric boundary layer over the Antarctic Plateau. Results showed that observed changes in wind speed and direction with height in the boundary layer coincided with the theoretical calculation of the Ekman spiral. The wind speed increased rapidly with height and the wind direction moved to the left. The vertical structure was therefore characteristic of the Ekman layer in the Southern Hemisphere. The Ekman boundary layer was high in the atmosphere, from 900 to 3400 m, with a dry, cold, and stable stratification throughout the layer, while the convective mixing layer was below 900 m. Our observations revealed a complex and dynamic structure in the atmospheric boundary layer over the Antarctic Plateau. Ekman equation calculations showed that turbulent friction stress over the Antarctic Plateau is significantly higher than over the lower latitudes. Dynamic friction from the atmospheric boundary layer over the Antarctic Plateau is likely to have important impacts on the global atmospheric circulation.