Acoustic tomography in the Florida Strait: Temperature, current, and vorticity measurements

Various aspects of near‐bottom ocean variability, including the alongshore temperature and current, the cross‐slope temperature, the onshore‐offshore flow, and the area‐averaged relative vorticity on the western slope of the Florida Strait near 27°N have been measured with a three‐point acoustic reciprocal transmission. Three pairs of reciprocal travel time data were extracted from acoustic pulse responses of a 1983 (August) triangular transmission experiment. Temperatures and currents were estimated from the sum and difference, respectively, of reciprocal travel times, and an area‐averaged vorticity was estimated from circulation following Stokes' theorem. The estimations agree well with the concurrent direct measurements at two nearby moorings. Low‐frequency fluctuations of temperatures, currents, and vorticity show a strong weekly period, clearly and consistently describing a near‐bottom onshore‐offshore water movement on the western slope in association with the Gulf Stream meanders.