Numerical Simulations of Gulf Stream Meanders and Eddies and Their Effects on the Cross-Shelf Transport off the Carolina Coast

Abstract

Gulf Stream meanders and eddies off the Carolina coast are studied using an ocean numerical model. Numerical simulation results show that the isobathic curvature in the vicinity of the Charleston Bump has great effect on the development and evolution of Gulf Stream meanders and eddies, and the formation of the Charleston Trough, a Gulf Stream meander that appears as a low pressure or depressed water surface region downstream of the bump, is the result of the combined effect of the Charleston Bump and the isobathic curvature in the region. The isobathic curvature plays a major role in enhancing the baroclinic and barotropic energy transfer rates, whereas the bump provided a localized mechanism to maximize the energy transfer rate downstream of the Charleston Bump.

The effects of the Gulf Stream meanders and eddies on the cross-shelf transport near the Carolina coast are also studied in the ocean numerical model. There are two factors that affect the ocean circulations on the continental shelf off the North and South Carolina coast: wind and the Gulf Stream meanders and eddies. It is concluded that the combination of the wind effect and the effect of the Gulf Stream meanders and eddies caused the red tide bloom event in the North Carolina near shore waters in October 1987. Neither wind alone nor the Gulf Stream meander/eddy alone is sufficient to transport the passive tracer to the near-shore area.