Abstract

An isopycnic coordinate numerical model is configured as an infinitely long channel with the width and bottom topography of the Straits of Florida at 27N to investigate the possibility that Florida Current meanders are due to dynamical instabilities. One mass/flow configuration with which to initialize the model is developed primarily from theoretical considerations, a second from the analysis of ST ACS observations (Leaman et al., 1987). To ascertain the effect of the bottom topography, flat bottom experiments are first examined. The current is found to be baroclinically unstable in the classical sense (Eady, 1949) to perturbations with wavelengths greater than ∼85 km, and the meanders which develop eventually dominate the channel flow pattern. When the 27N topography is included, the instability is greatly reduced, but the primary source of perturbation energy remains the baroclinic one. The meanders thus produced have wavelengths, periods, and amplitudes similar to those documented in the literature (Schmitz and Richardson, 1968; Lee and Mayer, 1977; Johns and Schott, 1987). The results are briefly compared with De Szoeke's (1975) application of his theory of modified Eady and hybrid instabilities to the Straits of Florida. From an energetics standpoint the instabilities in the model appear to be similar to the latter. From the point of view of wavelength, period and e-folding time of the most rapidly growing wave, however, they most resemble the topographically modified Eady instabilities.

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