Florida Current meandering and evolution of cyclonic eddies along the Florida Keys Reef Tract: Are they interconnected?

Abstract

The Florida Current (FC) is the branch of the Gulf Stream system within the Straits of Florida, connected to the Loop Current in the Gulf of Mexico. Cyclonic, cold-core eddies travel along this oceanic current system, entering the Straits of Florida in the vicinity of the Dry Tortugas and evolving along the Florida Keys island chain and coral reefs. The development of the high-resolution (∼900m) hydrodynamic model Florida Straits, South Florida, and Florida Keys (FKeyS), nested within a Gulf of Mexico model (both based on the Hybrid Coordinate Ocean Model), has enabled new findings in eddy variability. Together with high-resolution (∼1km) ocean color imagery, multiyear model archives have been employed to study the changes in the position of the FC front and the relationship with eddy evolution. It was found that eddy interactions and transformations are common, with multiple eddy cells within individual eddies or new cells emerging from existing vortices. Features in the Dry Tortugas area previously thought to be semipermanent are shown to be frequently transformed and/or replenished. A mechanism of local cyclogenesis is also proposed. Incoming eddies interact with and influence the downstream propagation of previous eddies. Systems of eddies, rather than individual vortices, can form the elongated features observed between the FC front and the Atlantic Florida Keys Shelf. Topography plays an important role in eddy dissipation or growth. A close synergy between eddy evolution and FC meandering is revealed. The results have implications on the connectivity of remote coastal and reef ecosystems. Copyright 2012 by the American Geophysical Union.