Effect of an axially-symmetric cyclonic vortex on the sea surface temperature in the Gulf of México

Abstract

A model for the mixed layer of the Gulf of México has been used to determine the effect that an idealized cyclonic vortex has in the sea surface temperature. The model consists of the equations of conservation of thermal energy and this of balance between mechanical energy and thermal energy, last based on the Kraus- Turner theory; both equations are vertically integrated in the mixed layer. As atmospheric forcing, we prescribe the surface wind associated with an axially-symmetric cyclonic vortex characterized by two parameters: the maximum tangential velocity and the radius at which that velocity is reached. The values of these two parameters, which depend on the position of the vortex, correspond to two cases: hurricane Hilda, which crossed the central part of the Gulf of México between September 29 and October 3, 1964 and hurricane Gilbert whose trajectory between 11 and 17 September, 1988 crossed the Caribbean Sea, the Yucatán Peninsula and the southwest Gulf of México. The results show that a cyclonic vortex with such characteristics, produce during its passage by the sea vertical turbulent water transport through the thermocline (entrainment) that is able to cool down the mixed layer in several degrees and increases the thermocline depth in several meters, in agreement with the observations.