Observations of the Response of Thermocline Currents to a Hurricane

Abstract

In September 1985, the eye of Hurricane Gloria passed within about 100 km of a current meter mooring in the western North Atlantic. Data from this mooring provide a clear view of the vertical structure of the near-inertial wake in the main thermocline. The response at 159 m was strong ({>}25 cm s−1 amplitude) and lasted about 18 days. At greater depths, the response was weaker and more irregular. The phase of the near-inertial currents increased with depth, consistent with the downward spreading of enemy. The total phase change across the thermocline reached about a half cycle seven days after the hurricane's passage, indicating a large vertical scale of the response. The observations are briefly compared with other time series measurements (on the continental margin) and with models.