The Leeuwin Current in the Parallel Ocean Climate Model and applications to regional meteorology and fisheries

Abstract

Unlike other currents along the subtropical west coasts of continents, the Leeuwin Current off Western Australia transports warm, fresh tropical waters poleward and is strong enough to overwhelm the upwelling tendencies of the coastal wind stress. The representation of this unusual and important current in the global eddy-permitting ¼° Parallel Ocean Climate Model (POCM) is examined, and implications for coastal fisheries and regional weather and climate discussed. Comparison of POCM fields with those from the Leeuwin Current Interdisciplinary Experiment for austral autumn and winter 1987 suggests that model Leeuwin Current is consistent with these observations in terms of its location and depth distribution, surface gradients and meridional variation in mixed layer depths but is a bit weaker, warmer and fresher. The model Leeuwin Undercurrent is similar in strength to that observed during autumn/winter 1987. Similar to satellite observations, the model Leeuwin Current displays a number of meander, eddy and offshoot features. The frequency distribution and length scales of the model features are generally consistent with estimates of these parameters derived from the satellite images. It is concluded that POCM output can be usefully applied to improve understanding of the Leeuwin Current and associated regional impacts.