Circulation and Heat Fluxes during the Austral Fall in George VI Sound, Antarctic Peninsula
Ryan D. Dorland and Meng Zhou
University of Massachusetts, Boston, Boston, MA 02125, USA
An intensive mesoscale survey was conducted in northern George VI Sound as part of the US Southern Ocean GLOBEC program in the austral fall, 2001 to determine the hydrography and its impacts on the Antarctic winter ecosystem. The absolute dynamic height field estimated from a combination of ADCP and CTD data reveals coastal jets intruding from Marguerite Bay and mesoscale eddies entrained within the sound. Temperature and salinity measurements indicate the presence of the modified Circumpolar Deep Water throughout the survey area. Vertical velocities were computed based on quasi-geostrophic dynamics revealing vertical circulation cells associated with the coastal mesoscale jets and eddies. Heat fluxes determined from horizontal and vertical advection of temperature gradients were comparable to surface heat fluxes that are critical to local ice formation. The revealed coastal currents and eddies created the physical and biological environment favorable for the survival of higher trophic seabirds and mammals during austral winter in Marguerite Bay.