Long-Term Coastal Upwelling over a Continental Shelf–Slope

Abstract

Abstract Long-term coastal upwelling over a continental shelf-slope with emphasis on the planetary dispersion of Rossby waves is studied with numerical models. The ocean is forced by a wind stress with a limited longshore extent. The thermocline intersects the shelf–slope and the internal radius of deformation is smaller than the width of the shelf-slope. Two case studies with and without the β effect are studied. lie early-stage response within a week or so is similar between the two. For an f-plane case, the whole-stage response is accounted for by coastal-trapped wave dynamics, and only equatorward flow exists over the shelf–slope at an advanced stage. However, inclusion of the β effect leads to a significant change in the alongshore flow pattern at the advanced stage. Due to the westward Rossby dispersion of the equatorward flow associated with the first and second coastal-trapped mode responses, the poleward undercurrent develops in the thermocline layer over the shelf. The time for the undercurrent ...