On the annual cycle of the sea surface temperature and the mixed layer depth in the Gulf of México

V. MANUEL MENDOZA, E. E. VILLANUEVA, JULIAN ADEM

Abstract

Using an integrated mixed layer model we carry out a simulation of the annual cycle of the sea surface temperature (SST) and of the mixed layer depth (MLD) in the Gulf of México. We also compute the annual cycle of the entrainment velocity in the deepest region of the Gulf of México. The model is based on the thermal energy equation and on an equation of mechanical and thermal energy balance based on the Kraus- Turner theory; both equations are coupled and are vertically integrated in the mixed layer. The model equations are solved in a uniform grid of 25 km in the Gulf of México, the northwestern region of the Caribbean Sea and the eastern coast of Florida. The surface ocean current velocity and the atmospheric variables are prescribed in the model using observed values. We show the importance of the Ekman pumping in the entrainment velocity. We found that the upwelling plays an important role in increasing the entrainment velocity, producing an important reduction in the SST and diminishing the depth of the mixed layer in the Campeche Bay. In the rest of the Gulf of México the downwelling tends to reduce the entrainment velocity, increasing the SST and the MLD. Comparison of the computed annual cycle of the SST and the MLD with the corresponding observations reported by Robinson (1973), shows a good agreement. In the deepest region of the Gulf of México, the photosynthetic pigment concentration data obtained from the Mexican Pacific CD-ROM of environmental analysis shows significative correlation with the computed annual cycle of the computed entrainment velocity only in January, April, May, June and September.

Keywords

Sea surface temperature; mixed layer depth; Gulf of México

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