Long-Term Observations of a Coastal Countercurrent on the Southeast Florida Shelf

Coastal circulation along the southeast Florida shelf is strongly related to the dynamics of the Florida Current as a part of the western boundary current system. We have conducted long-term observations with a mooring array deployed on the Ft. Lauderdale FL shelf. The array consists of a bottom ADCP mooring at 11 m isobath on the Dania Beach Shelf providing almost continuous observations since 1999 and a bottom ADCP mooring deployed on the Miami Terrace near Pompano Beach at 240 m isobath since 2007. There is a strong variability of the coastal current at this location on time scales ranging from hours to months, which is explained by the proximity to the Florida Current. An interesting feature revealed during these observations is an intermittent coastal countercurrent. This coastal countercurrent is seasonally modulated, reversing its direction during the summer season. The appearance of the countercurrent on the southeast Florida shelf and its relation to the Florida Current and undercurrent have not yet been completely understood. The possible physical mechanism behind this feature of the coastal circulation on the Southeast Florida shelf and practical applications are being discussed.