The deflection and division of an oceanic baroclinic jet by a coastal boundary: A case study in the Alboran sea

Abstract

An oceanic baroclinic jet impinging on a coastal boundary represents a particular type of ocean-coast interaction. This specific oceanographic phenomenon is an example of the stagnation in line flows occurring in fluid dynamics with three additional features: rotation, stratification, and a sloping boundary. In this study the authors describe the density, vorticity, and deformation characteristics of an oceanic jet impinging on a sloping boundary. The case study corresponds to the impinging process of the Atlantic jet at the African coast (Alboran Sea). In the impinging region, the acceleration field is divergent related to the fact that the magnitude of the deformation is larger than the magnitude of the rotation. It is also found that the stagnation streamsurface does not lie in a vertical plane but tilts in the opposite direction to the tilt of the isopycnals. The flow upstream of the stagnation point is characterized by backing, speed convergence, diffluence, and negative streamwise vorticity. The flow past the stagnation point is characterized by veering, speed divergence, confluence, and positive streamwise vorticity. The current can only be considered irrotational in a narrow part of the impinging region.