Long shelf waves generated by a coastal flux

Abstract

Solutions are presented for the shelf response of barotropic and stratified oceans to an oscillatory coastal flux through a strait. The flux is modeled as the return interior flow due to an Ekman transport that arises from a fictitious square‐wave longshore wind stress. The width 2 d, of the square‐wave stress is taken to be that of the strait and the response due to the coastal flux determined from longwave wind forced solutions that exist in the literature. The net longshore energy flux for the nth strait forced shelf wave mode, wave number kn, is shown to be proportional to [bnsin(knd)( knd)]2, where is the coastal flux spectrum and bn the modal “wind” coupling coefficients. Results compare favorably with existing barotropic theories and estimates of net longshore energy flux obtained for the Australian Coastal Experiment region are shown to be in reasonable agreement with observations at periods of 9 days, when forcing by Bass Strait is assumed greatest.