Observations of warming on the Western Australian continental shelf

Global temperature datasets indicate a warming trend in the south- eastern Indian Ocean of similar to 0.02 degrees 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 degrees C year(-1) since 1951, corresponding to similar to 0.6 degrees C over the past 5 decades. Measurements from three other shallow stations between 1985 and 2004 indicated warming trends of 0.026- 0.034 degrees 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 Ni (n) over tildeo/ Southern Oscillation ( ENSO)- related events in coastal sea level and hence the Leeuwin Current.