The structure and propagation of a Gulf Stream frontal eddy along the North Carolina Shelf Break

Abstract

The Frontal Eddy Dynamics (FRED) experiment, conducted offshore North Carolina between Cape Fear and Cape Hatteras, included a multiplatform intensive survey phase in May 1987. The intensive phase data set includes satellite infrared imagery, aircraft‐ and shipboard‐deployed expendable bathythermographs, moored current meters and thermistors, and satellite‐tracked drifting buoys. These observations are used to examine the structure and propagation of Eddy Abbott, the most extensively surveyed frontal eddy in this study. The analysis includes the use of a frontal eddy feature model to calculate the surface circulation and propagation characteristics of Eddy Abbott's cold dome from the buoy trajectories. The observations and analyses presented are unique in that Eddy Abbott is the first Gulf Stream frontal eddy seeded with tracking buoys to be followed beyond Cape Hatteras. Previously, frontal eddies were assumed to be sheared apart as they approached the confining topography of Cape Hatteras, leaving the near surface nutrient rich waters of the cold dome stranded on the North Carolina shelf. The in situ tracking data provided by the buoys indicate that rather than being stranded, Eddy Abbott's cold dome accelerates, propagating out of the South Atlantic Bight beyond Cape Hatteras.