Observations of warming on the Western Australian continental shelf

Global temperature datasets indicate a warming trend in the south-eastern Indian Ocean of ~0.02°C year–1. This is supported by in situ temperature measurements at a coastal monitoring station on the Western Australian continental shelf that have shown a mean temperature rise of 0.013°C year–1 since 1951, corresponding to ~0.6°C over the past 5 decades. Measurements from three other shallow stations between 1985 and 2004 indicated warming trends of 0.026–0.034°C year–1. It is suggested that enhanced air–sea heat flux into the south-eastern Indian Ocean may be a key factor in the rising temperature trend. There has also been a steady rise in salinity over the past half-century. At interannual scales, coherent temperature variability at the various stations indicates that larger-scale processes are influencing the shelf waters and are linked with El Niño/Southern Oscillation (ENSO)-related events in coastal sea level and hence the Leeuwin Current.