Response of the Coastal Ocean to Hurricanes Floyd and Irene at the South Florida Ocean Measurement Center

Hurricanes Floyd and Irene passed near or through the NSU/USF three-dimensional monitoring array installed at the South Florida Ocean Measurement Center (SFOMC) experimental range, south of Port Everglades, Florida. The mooring array contains acoustic Doppler current profilers (ADCPs), a combination of recording temperature and temperature/ salinity sensors, a wave and water level gauge, and a meteorological package. Data from these sensors has been collected continuously since July 1999. Category 4 hurricane Floyd ravaged portions of the central and northwest Bahamas on Sept. 13-14, 1999, eventually making landfall near Cape Fear, N.C., as a Category 2 hurricane on Sept. 16. At the South Florida shelf, the local response to Hurricane Floyd was relatively weak; however, we observed a significant non-local response of the upper ocean to this hurricane. Within three days after the passage of the hurricane, the mean sea level dropped by ~0.25 m, and the along shore current reversed its direction from south to north. Category 1 Hurricane Irene passed through the mooring array on Oct. 15-16, 1999. In this case, we observed a significant local response of the coastal ocean. For a few hours, the significant wave height exceeded ~4 m at the 11-m isobath, the along shore current speed increased by ~1 knot (0.5 m/s), and the turbulence levels (as derived from boundary layer laws) increased dramatically. There were, however, no appreciable changes in sea level.