2006 Ocean Sciences Meeting SEACOOS Poster - Observing Eddy Activity Using Wellen Radars and a Moored Acoustic Doppler Current Profiler in the Florida Straits

For the program on "Application of High-Frequency Radar Technology for Coastal Oceanographic Studies III Posters," OS25I-12. As part of the ONR sponsored Southeast Atlantic Coastal Ocean Observing System, a high-frequency Wellen-Radar (WERA) system is currently operated and maintained by the University of Miami's Rosenstiel School of Marine and Atmospheric Science along the Eastern Florida Shelf. Two radars, stationed at Key Biscayne and Key Largo, transmit at a frequency of 16MHz with a typical range of 80 to 100 km. Over a sample interval of 10 minutes, the WERA effectively maps the surface current at a resolution of approximately 1 km at 5000 cells. These data are averaged hourly, plotted on a 2.4 km grid and uploaded to the World Wide Web in near-real time. Since the Eastern Florida Shelf WERA system's inception, complex coastal ocean circulations have been observed including both mesoscale and submesoscale eddy events and Florida Current meanders. In the radar footprint, a detailed analysis of the subsurface structure of these features is attained using acoustic Doppler current profiler (ADCP) data from a mooring located off of Elliot Key at 86-m depth. During a 9-month period (September 2004 to June 2005), several current reversals were observed at the mooring site. Forty-hour, low-pass filtered currents indicate a high amount of variability in the subsurface ocean structure during the passage of mesoscale and submesoscale surface current events. Comparison with sea surface temperatures from the Advanced Very High Resolution Radiometer (AVHRR) and Moderate Resolution Imaging Spectroradiometer (MODIS) suggest that some current reversal events are linked to the downstream propagation of Tortugas Eddies, a semi-permanent mesoscale feature, while others are caused by wind forcing. During periods of observed eddy activity, the combination of surface and subsurface structure provides insight into the role of mean flow advection by the Florida Current. *A B Parks, L K Shay, W E Johns, T M Cook, B K Haus, J Martinez-Pedraja