As part of the Group C PATOMAC cruise on the RSMAS research vessel F. G. Walton Smith in August 2003, four surface drifters were deployed about 50 kilometers east of Miami to measure the rate of turbulent dispersion of drifting particles (such as billfish larvae) in the Florida Current.

This was our second attempt at deploying two of the drifters. They had been initially deployed during the first PATOMAC cruise in July 2003, but within days were picked up by a sportfisherman and ended up in a bar next to a dock in Cape Canaveral, FL. You can read about it here .

At first, the four drifters kept very close to each other. Although it cannot be seen in the graphic, the drifters kept within a kilometer of each other during this segment.

The drifters were deployed near the center of the Florida Current, part of the Gulf Stream System. The current is constrained to flow in the Straits of Florida, a 100 kilometer wide, 850 meter deep channel (at Miami's latitude) between Florida and the Bahama Banks. The flow is fairly linear in this region, with relatively minor fluctuations in the flow, mostly along the sides. As the jet exits the Straits of Florida it is no longer constrained by the channel and tends to develop large wavelike meanders which sometimes pinch off to form rings, particularly in the region downstream of Cape Hatteras, North Carolina. The diverging drifter tracks are consistent with this meandering behavior.

Numerous studies have also suggested that the New England Seamount Chain at 66°W longitude also has a major influence on the flow; in this regard, note how the drifters diverge sharply at this longitude.

Here is the latest map of the drifters trayectories: