Circulation and heat fluxes during the austral fall in George VI Sound, Antarctic Peninsula

A mesoscale survey was conducted in northern George VI Sound as part of the United States Southern Ocean Global Ocean Ecosystems Dynamics program in austral fall 2001 to examine the circulation and heat fluxes. The absolute dynamic height field is determined from a combination of measured currents detided using model-predicted tidal currents, streamfunction fitting, and the thermal wind equation based on hydrographic measurements. The results have revealed surface coastal currents of 0.2 m s−1 intruding into northern George VI Sound from Marguerite Bay (MB) and mesoscale eddies formed within the deep trough. Both Antarctic surface waters and modified circumpolar deep water were transported into the sound along the eastern side of the sound while ice shelf influenced waters exited to MB along the western side. Analysis indicates that predominant southward winds during the season were responsible for driving the basin-wide circulation in the sound. Both convergence of horizontal heat transports and vertical upwelling heat fluxes were significant to the contribution or delay of local ice formation in George VI Sound, which is critical for the austral winter ecosystem.