An investigation of tidal and nontidal current patterns in Western Hawk Channel, Florida Keys

Current and wind data collected during the summer of 1992 and the fall and winter of 1993–1994 are used to characterize near-bottom flow patterns at a study site in Hawk Channel southwest of Key West. Currents are dominated by along-channel motions with low-frequency reversals occurring over time scales of 2–3 weeks. A seaward deflection of along-channel flow is apparent in both records. Harmonic analysis indicates that tidal co-oscillations contribute 6–10% and 48–70% of the total variance of the along-channel and across-channel currents, respectively. Spectral analysis indicates a close coupling between along-channel wind stress and along-channel currents at periodicities of 2–3 days. A comparison of across-channel winds and across-channel currents suggests an inverse relationship indicating an upwind return flow of near-bottom currents.