Climate Variability of the Gulf of Mexico Coastal Ocean

Sea surface temperature (SST) within the Gulf of Mexico shows considerable seasonal and inter-annual variability. Some of this is accounted for by local air-sea fluxes, but an equally important amount is due to ocean dynamics, especially those associated with coastal upwelling and the Loop Current. Specific regions of importance are the bounding coastlines in the north, east, and west, and the Campeche Banks in the south where cold waters derive from seasonal upwelling. In contrast to these coastal regions is the mid-basin where Loop Current intrusions of a more stochastic nature deliver warm water. These cold coastal and warm mid-basin regions combine to produce the basin-wide SST gradients and the variations in the surface heat, moisture, and momentum fluxes that control the ocean-atmosphere system of the Gulf of Mexico. AVHRR imagery exhibits inter-annual variability in the intensity of the seasonal SST contrasts. Differences are noted between such imagery, in-situ measurements, and the NCEP reanalysis fields. Reconciling these differences and their impacts on the climate variability of the Americas provides challenges to coupled ocean-atmosphere models and their supporting observing systems.