Accession Number : ADA115519

Title :   Oceanic Frontal Stability: A Numerical Model,


Personal Author(s) : Martin,Wayne W

PDF Url : ADA115519

Report Date : Nov 1981

Pagination or Media Count : 147

Abstract : A stable, convergent numerical model has been developed to study the evolution of mesoscale meanders of oceanic fronts. A finite difference model was used with the frontal zone divided into two regions, a dissipative zone near the surface expression of the front, and an inviscid region where the frontal interface was deeper. The parameters studied were: wavelength/Rossby radius ratio, amplitude/wavelength ratio, and cross stream Froude number. Tests were run using oceanographic conditions representative of two regions, the Gulf Stream downstream of Cape Hatteras, and the Sargasso Sea at 30 deg N. The model was shown to be sensitive to the wavelength.Rossby radius ratio. For the Sargasso Sea conditions a 30 km disturbance was more stable with respect to amplitude growth than a 100 km disturbance. Both the magnitude and sign of the cross stream Froude number affected the meander stability, with a negative Froude number (downward entrainment near the surface front) showing the greatest amplitude growth. The model results were very sensitive to the meander amplitude. The growth rates from large amplitude tests were much lower, and closely matched observational results. This model also showed a tendency toward growing inertial period oscillations near the boundary between the dissipative and inviscid regions.

Descriptors :   *Fronts(Oceanography), Variations, Stability, Amplitude, Ocean models, Gulf stream, Sargasso Sea

Subject Categories : Physical and Dynamic Oceanography

Distribution Statement : APPROVED FOR PUBLIC RELEASE