Low-frequency baroclinic waves off coastal boundaries.

Abstract

Investigates the behaviour of low frequency baroclinic Rossby wave motion in the vicinity of coastal boundaries using linearized modulated wave theory in a stratified constant depth equatorial beta plane ocean. The vertical momentum balance is assumed to be hydrostatic and the Boussinesq approximation is used. The solution in the interior, consisting of a modulated Rossby wave, an equatorial Kelvin wave and a term forced directly by wind stress, is constructed separately for each component. Shows how these separate solutions may be linked through the boundary conditions at the coast. Evaluates also the energy fluxes for the three components of the solution, and provides critical latitude analysis. Studies the nature of the transition from offshore propagation to coastal trapping in the ocean interior around the critical latitudes. The derived amplitude and phase variations of coastal pressure are qualitatively different below and above the critical latitude. Values of critical latitude depend on frequency and the angle of the coastline, decreasing as the frequency increases and the orientation departs from straight north/south. Notes the difference in behaviour along the northern and southern Hemisphere boundaries induced by variations in the coastline geometry.