Blocking of Steady Circulation by Coastal Geometry

Abstract

Along the southern Turkish continental shelf, the intensity of the observed mean flow has a considerable degree of variability. The relatively strong currents along the straight portion of the coast is reduced significantly in the nearshore region upon encountering irregularities in the form of bays and headlands. As a possible explanation of such blockage by coastal irregularities, a linear, homogeneous wind-stress free model is presented incorporating the constraints of topographic steering and linear bottom friction. Solutions are given for an idealized case of an abrupt indentation on a straight coast adjoining a linearly deepening shelf. The directions preference of blocking and the applicability of boundary layer approximations am discussed. Numerical solutions are obtained for the realistic bathymetry and coastal configuration along the southern Turkish continental shelf. The concepts developed are applied to the observed blocking features.