2.2 Dynamics and impacts of the Leeuwin Current

Description

This project documented oceanography, multidecadal trends and quantitative heat budgets in the warming regions of the eastern Indian Ocean, including the equatorial and Leeuwin Current regions.

Standard techniques of time series analyses and linear regression documented multi-decadal trends in surface and subsurface temperature, sea level, and weather variables, as well as the results from long term numerical model simulations forced by observed wind stress. The analysis used three fine scale ocean models (two from the BlueLink project and a fine scale model developed by French and German colleagues). The seasonal, interannual, and decadal variability of the Leeuwin Current and its heat balances were studied using these models.

In addition, the influences of the Indian Ocean Dipole sea surface temperature anomalies on wind patterns in the Leeuwin Current region were assessed.

In order to link physical oceanography and biology, the role of ocean eddies and other mesoscale structures in the ecosystem of the Leeuwin Current was identified using satellite-observed sea surface height and sea surface temperature (SST) and observations from a number of Southern Surveyor cruises. The goal was to understand the cross-shelf processes and their biological impacts.

Aims

• An understanding of the mechanism of warming in the tropical eastern Indian Ocean
• An understanding of the multi-decadal trends in the Leeuwin Current;
• An improved understanding of the response of the Leeuwin Current system to inter-annual climate variability by using BLUELink model simulations;
• An understanding of the role of the Leeuwin Current eddies in cross-shelf transport;
• Projected future changes in the Leeuwin Current system;
• Model-data archive and report on downscaled, regional (10 km) climate change scenario of the marine environment.

Reports

Feng M, McPhaden M.J., Lee T. Decadal variability of the Pacific subtropical cells and their influence on the southeast Indian Ocean. Geophysical Research Letters (2010) doi.org/10.1029/2010GL042796

Feng, M., Weller, E. and Hill, K. (2009) The Leeuwin Current. In A Marine Climate Change Impacts and Adaptation Report Card for Australia 2009 (Eds. E.S. Poloczanska, A.J. Hobday and A.J. Richardson), NCCARF Publication 05/09, ISBN 978-1-921609-03-9.

Holbrook, N.J., Davidson, J., Feng, M., Hobday, A.J., Lough, J.M., McGregor, S. and Risbey, J.S. (2009) El Niño-Southern Oscillation. In A Marine Climate Change Impacts and Adaptation Report Card for Australia 2009 (Eds. E.S. Poloczanska, A.J. Hobday and A.J. Richardson), NCCARF Publication 05/09, ISBN 978-1-921609-03-9.

Media