Seasonal Wind and Ocean Thermal Forcing Influences on the Generation of the Leeuwin Current and Its Eddies
Abstract
A high-resolution, multi-level, primitive equation ocean model is used to examine the response of an idealized, flat-bottomed, eastern boundary oceanic regime on a beta-plane to constant ocean thermal and wind forcing by annual mean and seasonal mean climatologies. The focus of the study is the Leeuwin current along the coastal region, from 200 S to 350 S, off Western Australia. The annual mean ocean thermal forcing in sufficient to produce a poleward surface coastal current and an equatorward undercurrent. Seasonal variation of the ocean thermal forcing provides little enhancement to the current structure, although the seasonal variation does enhance eddy generation during the periods of stronger thermal gradient. Wind forcing by annual mean climatology significantly inhibits the poleward coastal flow, but does not eliminate it. Seasonal wind forcing generates a strong seasonal signal in the poleward coastal flow, but never dominates over the pressure gradient forcing. The combination of wind and thermal cycles allows the formation of the North West Shelf waters and, subsequently, triggers the release of poleward flowing North West Shelf waters. This additional forcing produces a strong surge in poleward flow during the austral autumn. A nonlinear feedback mechanism acts to extend the duration of this flow through the austral winter.
Document Details
- Document Type
- Technical Report
- Publication Date
- Sep 01, 1991
- Accession Number
- ADA246992
Entities
People
- Eric J. Bayler
Organizations
- Naval Postgraduate School