2006 Ocean Sciences Meeting SEACOOS Poster - HF Radar Wave Measurement Over a High Current Shear Region in the Florida Straits

For the program on "Application of High-Frequency Radar Technology for Coastal Oceanographic Studies III Posters," OS25I-14. Two High Frequency Wellen Radars (WERAs) have been operating in Southeast Florida since June 2004 as a part of the Southeast Atlantic Coastal Ocean Observing System (SEACOOS). The 16 MHz systems illuminate a large area of the Florida Straits, which is dominated by the highly variable Florida Current system. Typically a 125 KHz bandwidth continuous wave is transmitted, which allows surface radar backscatter data to be acquired at ranges up to 110 km on a 1.2-km grid every 10 minutes. The backscattered Doppler spectrum is then processed at 5000 locations for each sample to provide real-time near-surface current measurements. An on-offshore transect of these spectra with samples every 1.2 km, from 3-30 km offshore is then processed to extract significant wave height (Hs) estimates, which are displayed in real time. The calibration coefficients required for this empirical approach were derived from comparison with in-situ measurements conducted in spring 2004. More sophisticated processing of the backscattered spectra to obtain the directional wave-spectra at up to 1000 locations per sample is done in an off-line mode. This is primarily because of the low-bandwidth available for real-time data transmission. The fetch-limited wave growth when the winds are directed offshore was computed over a range of non-dimensional fetches. The growth of wave energy compares well with previous empirical formulations, where the scatter is of the same order as in-situ wave observations. However, the wave energy deviates significantly from the empirical formulations as the waves propagate across the high current shear region along the western boundary of the Florida Current due to wave-current interactions. *B K Haus, R J Ramos, T M Cook, L K Shay, P A Work, G Voulgaris, L R Wyatt, J Martinez-Pedraja