Nearshore Wave and Current Measurements During Hurricane Jeanne

摘要

Waves, currents, and storm surge generated by Hurricane Jeanne were measured at Melbourne Beach, FL using an Acoustic Doppler Current Profiler (ADCP) instrument deployed in 8.5 meters depth, approximately 610 meters from the dune. An unusual loop in Jeanne's track during its approach resulted in a five-day period (Sept. 20-24, 2004) of nearly uniform, moderate wave conditions (H_(mo)～2m, T_(pk)～11s). However, upon landfall early on Sept. 26, significant wave height approached 3.8 meters, maximum storm surge was 1.5 meters above predicted tide, and currents rapidly switched from 0.8meters/second to the south to 1.1 meters/second to the north. Close scrutiny of the high-resolution, fully directional spectra provided by the ADCP reveals broad-banded, direc-tionally narrow spectra before landfall, followed by narrow-banded, directionally broadened spectra after landfall. Directional spreading was slightly skewed to the north before landfall, switching to slight skewness to the south after landfall.