Satellite scatterometer-derived air-sea fluxes for numerical modeling of the upper ocean response to tropical cyclones

An atmospheric flux model is coupled to the Navy Coastal Ocean Model, which has been configured to simulate the Gulf of Mexico. The flux calculations are adapted from the Bourassa-Vincent-Wood flux model, which includes dependence on atmospheric stability, near-surface winds, sea state and the influence of capillary waves. This flux model has been shown to perform well for low and relatively high wind speed scenarios. Wind fields derived from satellite scatterometer data, along with numerical weather prediction data, are input to the flux model along with the ocean model surface temperature fields. The resultant fluxes are applied to the ocean model as surface boundary conditions. The goals of this research are to accurately simulate the ocean's response to air-sea fluxes associated with tropical storms and hurricanes, and to investigate further the mechanisms by which air-sea heat exchange and momentum fluxes modify the thermal structure of the upper ocean. The importance of upwelling and entrainment versus surface heat loss, and the role of vertical mixing, are examined for both relatively weak and strong tropical systems. Particular case studies include T.S. Harvey (1999) and Hurricane Dennis (2005). The ocean model is initialized from a data assimilative analysis run to produce a realistic upper ocean thermal structure, so that the impacts of variations of the upper ocean heat content on the ocean surface response to the storms can be investigated.