9315920 McPhee The proposed work is part of an integrated research program ("Anzflux") into the oceanographic structure of upper mixed layer of the eastern Weddell Sea. It is to be carried out from the RVIB Nathaniel B. Palmer in the austral winter of 1994. The work proposed here is an effort to define the vertical and horizontal thermohaline fluxes within the eastern part of the Weddell Gyre. Specifically, instrument clusters capable of measuring the Reynolds stress and the turbulent heat flux directly will be suspended from the sea ice near the ship for two separate fifteen day drift periods. Also, microconductivity sensors at three levels in the water will provide the directly measured salinity flux, and a number of thermistor strings frozen in the ice will measure the heat conduction within the ice and the ice mass balance. These measurements, in conjunction with other concurrent experiments to quantify the energy brought to the underside of the ice, will form the basis of a regional study of the processes responsible for the relatively thick upper mixed layer and thin ice cover. It is believed that these conditions are only marginally stable, and are maintained by a relatively high upward heat flux, which, if interrupted, could lead to deep vertical convection, and a significant change in the oceanic climate. ***
