{News} 081031! Drought woes to continue: Jamstec
Drought woes to continue: Jamstec
Weekly Times, October 31, 2008
BLEAK is the only way to describe Japanese forecasters' latest outlook for southeast Australia.
"Large parts of Australia will still suffer from the long-lasting drought (until) the end of this year," according to Japan's Frontier Research Center for Global Change, Jamstec.
Jamstec senior scientist Jing-Jia Luo said the group's Sintex computer model showed conditions would remain dry until January in southern Australia.
"Early next year, good rain might occur in association with the demise of IOD (Indian Ocean Dipole) and weak cooling in the central equatorial Pacific," Mr Jing-Jia said.
The Jamstec team, led by Prof Toshio Yamagata, has predicted the last three positive IOD events.
The group's most accurate modelling is based on pooled three-month outlooks across the Pacific and Indian oceans.
The Jamstec team produces monthly forecasts that show southeast Australia will experience a relatively dry October, some rain in November and a dry December.
The only month showing any promise of significantly higher than above-average rainfall is January.
Bureau of Meteorology climate analyst David Jones said the present three-year run of positive IODs was unprecedented.
"The sequence of the last three years has been very odd," Dr Jones said. "It's something we've not seen before. There's a real worry this is one of the things we expect with global warming."
Dr Jones said international climate-change models showed positive IODs and El Nino events becoming more frequent, in response to rising greenhouse gas levels.
But he said only a few of the numerous computer models predicted anything as severe as the last three years in southern Australia.
"Our climatic system is behaving very oddly," he said.
"We've had a decline in autumn rainfall in the past 30 years. Now we've had a sequence in the last five to six years where spring rain has declined. It's too early to call a trend, but it's a very odd pattern."
When the IOD is positive the sea surface temperatures around Indonesia and northern Western Australia are cooler than average. The cooler conditions reduce sea-surface evaporation, and moisture in the atmosphere. Reduced atmospheric moisture leads to a slump in the formation of crucial northwest cloud bands that sweep across the continent to deliver rain to southeast Australia.
Source: http://www.weeklytimesnow.com.au/article/2008/10/31/20555_national-news.html
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