RECENT climate research indicates destructive east coast low weather systems may become less frequent over the next century.
The latest Bureau of Meteorology and CSIRO studies both conclude that while extreme rainfall events and droughts are likely to increase, the destructive weather systems will decrease.
An east coast low is typically used to describe a low-pressure system that develops off Australia’s east coast between Brisbane and eastern Victoria.
The weather system relies on the interaction of cold air in the upper atmosphere with warm, moist air at lower levels. The mixture creates a strong temperature gradient that triggers heavy rain and strong winds.
Bureau of Meteorology data from 1973 to 2004 showed there were an average of 10 ‘‘significant impact’’ low pressure systems off the east coast each year. Normally only one of those systems displayed an ‘‘explosive’’ development pattern.
‘‘The difficulty in deciding on exactly what separates an east coast low from other systems is a very difficult question to answer,’’ Acacia Pepler, of the University of NSW’s climate change research centre, said.
‘‘However, recent research is suggesting that the frequency of east coast lows, particularly the major winter systems that cause large waves, may actually decrease over the coming century given climate projections.’’
Bureau of Meteorology climate change researcher Andrew Dowdy has predicted that the frequency of east coast lows may drop by 40per cent by 2100 if carbon dioxide levels continue to rise at their current rate. The CSIRO East Coast Cluster Report–Climate Change in Australia, published this year, also predicts a decline in the famous weather system.
The report suggests that there will be an overall decline in winter wind speed, however, intense rainfall events may increase.
‘‘Scientific literature suggests a decline in the number of east coast lows,’’ the report says.
The report also predicts droughts will extend for longer periods of time towards the end of the 21st century.