The Development of a Florida Current Climatology to Support the Redeployment of a Wave Monitoring Buoy

In April of 2018, the United States Army Corps of Engineers deployed a wave monitoring buoy 10 nautical miles south of Bahia Honda Key, an island 30 miles east of Key West, Florida. The buoy is operated and maintained by the Scripps Institution of Oceanography, as part of the nationwide Coastal Data Information Program. Engineers at the Coastal Data Information Program used surface current modeling, ship traffic archives, and Florida Keys National Marine Sanctuary boundaries to successfully position the buoy south of the Marine Sanctuary, north of the Florida Current, and away from potentially damaging ship traffic. For more than a month, the buoy reported wave height, wave period, wave direction, surface current, and sea surface temperature. This is the only buoy of its kind sampling wave height and surface current in the Straits of Florida. Unfortunately, the depth and the strength of the Florida Current overwhelmed the mooring system, forcing the buoy underwater and blocking transmissions to the Iridium satellite constellation. The Florida Current is subject to frequent meanders and eddies, such that the northern extent varies both daily and seasonally. High resolution surface current models attempt to simulate the complex interactions of the Florida Current and the adjacent small and large scale basins. However, the lack of in-situ verification from wave and current monitoring buoys limits the tuning and accuracy of these modeling systems.

To support the successful repositioning of the buoy by Coastal Data Information Program engineers, National Weather Service Key West performed a statistical analysis of the northern extent of the Florida Current at eight widely spaced points along the Florida Keys Reef Tract. The database used by National Weather Service Key West pulled from analyses produced by the Naval Oceanographic Office every three days. These Naval Oceanographic Office analyses use persistence, high resolution sea surface temperature data, and forecaster experience to create a north wall estimate with respect to known locations along the Florida Keys Reef Tract. Based on 12 years of Naval Oceanographic Office analysis archives, National Weather Service Key West estimated Florida Current deviations at the failed buoy location of at least 12.7% over the period studied. Coastal Data Information Program engineers are in the process of repositioning the buoy north of its present location to avoid persistently strong currents. The developed climatology, in conjunction with operational in-situ wave and current monitoring, and improved oceanographic models, will prove invaluable to not only the Coastal Data Information Program engineers and National Weather Service forecasters, but also to the vast, diverse, and vulnerable marine community of the Florida Keys.