El Niño and Indian Dipole Could Combine for Drought Double-Whammy on Eastern Australia

13 July 2009

The Australian. Eastern Australia could be slammed by the drought-inducing combination of an El Niño and a positive Indian Ocean Dipole (earlier post).

The Australian Bureau of Meteorology is putting the odds of an El Niño at more than 50%.

“The climate models are pretty much in agreement there will be a continued warming,” [Bureau meteorologist Andrew Watkins] said. “Most of them are saying there will be an El Niño later in the year.” El Niño events are linked with reduced rainfall in eastern, northern and parts of southern Australia in the second half of the year, and higher daytime temperatures. The last El Niño events occurred in 2002 and 2006, when, according to the bureau, “rainfall deficiencies were widespread and severe”.

...There is also growing interest in the influence the Indian Ocean has on Australia’s rainfall. The Indian Ocean Dipole, like El Niño, is a coupled ocean-and-atmosphere phenomenon. When it is in its positive phase, the Indian Ocean is cooler near Australia. Dr Watkins said scientists believed that a positive IOD reduced rainfall over southeastern Australia.

CSIRO scientist James Risbey said that there is a chance for a record for global mean temperatures this year with the El Niño.