Abstract

The energetics and dynamics of the Gulf Stream at 68W have been investigated using year-long time series of velocity and temperature throughout the water column. The major results that have emerged are as follows: (1) There is a net conversion of mean to eddy kinetic and potential energies, the barotropic mechanism being almost twice as strong as the baroclinic. These energy exchanges are dominated by what is happening in the upper 1000 m of the water column. (2) Comparison with other studies suggests that the mooring site may be characterized as a region of downstream spatial growth in eddy energy, with a growth rate of 3–4 × 10−3km−1. (3) Curvature changes due to the changing Stream path are sufficient to balance stretching of the water column below the thermocline, the dominant measurable effect in the vorticity equation. (4) A kinematic scheme including and relating barotropic cross-stream velocities, local temperature changes, stretching, and curvature changes is shown to be generally consistent with the observed data. (5) The vertical mass divergence ∂w/∂z affects continuity at lowest order, and may be associated with along stream changes in transport, a vertical redistribution of the alongstream momentum flux, or changing Stream width.

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