MELBOURNE, Jan. 30 (Xinhua) -- A rare mix of a tropical cyclone, moist airflows and stalled atmospheric waves has brought record-breaking heat to southeastern Australia, experts said Friday.
Meteorologists said the heatwave formed when a strong high-pressure system stalled over the inland regions and trapped hot air near the ground while delaying cooler fronts.
Disturbances in the jetstream -- fast-moving air currents high above the Earth -- helped the system linger for days, according to an article published on The Conversation website.
The system was intensified by Tropical Cyclone Luana, which hit the state of Western Australia last week and fed more moisture into the atmosphere, worsening the heatwave, said the article by Michael Barnes, research fellow from Australia's Monash University, and Tess Parker, research scientist from the Commonwealth Scientific and Industrial Research Organization, the national science agency.
Temperatures peaked at 48.9 degrees Celsius in the southeastern state of Victoria's Walpeup and Hopetoun, as some inland towns in the states of South Australia, New South Wales and Victoria sweltered up to 20 degrees Celsius above the late-January average, it said.
Meteorologists called the temperatures "incredibly abnormal," with the heatwave set to linger into Saturday in some areas.
"These cyclone-heatwave events are known as compound events, where several types of extreme weather overlap in time, space or both, and can act to intensify each other," the experts wrote.
Scientists said the ongoing southeastern Australia heatwave closely mirrors the 2009 heatwave that preceded Victoria's Black Saturday bushfires, warning that such "compound" weather extremes could become more frequent under climate change. ■
