Tidal and Sub-inertial Fluctuations in the Florida Current

Abstract

A 50-day time series was obtained from a current meter mooring in the Florida Current off Miami. The results agree with earlier observations regarding the significance of several-day oscillations in the Gulf Stream. The energy spectrum of the V component shows a pronounced peak at periods of 5–6 days with an amplitude of about 20 cm sec⁻¹. Quantitatively the results are reminiscent of barotropic shelf waves, although definite conclusions about the occurrence of such waves require additional observations. Analysis of tidal fluctuations shows that 25% of the variance in the V component and 6% of the variance in the U component can be accounted for by the four major constituents, M₂, S₂, K₁ and O₁. The largest constituent in the V component is the O₁ tide, whereas the K₁ tide dominates in the U component. The results are in good agreement with earlier observations from the sea surface, indicating that the vertical structure of the tides is predominantly barotropic.