Modeled surface heat fluxes over Terra Nova Bay polynya

Polynyas play an important role in the meteorology and oceanography of the polar regions and in the oceangeneral circulation.A winter event of Terra Nova Bay polynya, is studied by a recent version of the atmospheric, mesoscale Etamodel. Currently, the Eta model distinguishes open water grid points and thick sea ice grid points by a maskwhich is established as initial condition and remains fixed in the simulations. In the days of the event the mostof the model integration domain is under polar night condition and, in particular, the Sun is below the horizon atTNB. Thus, available AVHRR image does not contain the visible channels but only the thermal ones. In channel4 (11.5 m), AVHRR imagery show the area of TNB with a well developed warm area, corresponding to thepolynya as revealed by AMSR-derived SIC maps, surrounded by much colder pack ice. Brightness temperature,hailing from the satellite observations, decreases as one moves away from the coast towards the Ross Sea. Amulti-regions polynya was introduced in the model using different skin temperatures in order to take some accountof the variation of temperature with the distance from the coast. The polynya is therefore depicted as consisting ofa warm inner region, and two zones gradually colder. The surface heat fluxes, calculated over the polynya, and theimpact of polynya on the air above it will be presented.