Modelagem unidimensional da camada limite oceanica durante a passagem de uma frente fria na regi?o da confluência Brasil-Malvinas

摘要

A one-dimensional second order closure model is used to investigate the response of the ocean surface to the passage of a cold front in the region of the Brazil-Malvinas Confluence. In order to initialize, force and validate the model, data from a moored buoy ARGOS-23056, for the period between 12 and 20 January 2002 were used, corresponding to the passage of a cold front. The model was able to reproduce both the diurnal cycle and the cooling surface temperature observed with the passage of the cold front. Numerical simulation results showed an increased of 0.2oC in the cool skin effect and a deepening of approximately 16 meters in the oceanic mixed layer with the passage of the cold front. These variations were consistent with a change in surface energy balance, due to an abrupt increase in turbulent fluxes in response to the increased wind speed and the temperature difference between the air and sea. After the cold front passage, the heat fluxes decreased slowly, showing that if, there is no passage of another cold front neither water advection, the ocean surface and the air adjacent tend towards equilibrium.