Long-term changes in southern Australian anticyclones and their impacts
Anticyclones are one of the main synoptic features of the global midlatitudes, where they are associated with dry, settled conditions. Previous studies have identified southern Australia as a region where significant long-term changes have occurred in recent decades, including a decline in cool season rainfall and an increase in the frequency of anticyclones. This paper uses several reanalyses to assess the climatology, variability, trends and impacts of anticyclones in southern Australia and several subregions. A robust increase in the frequency of anticyclones in southern Australia is demonstrated between 1960–1979 and 1997–2014, particularly in southeast Australia and the Tasman Sea during the cool months of the year. At least 30% of the recent cool season rainfall decline in southeast Australia can be associated with an increased frequency of anticyclones in this region. However, there are no clear trends in anticyclone frequency near southwestern Western Australia, where long-term rainfall declines are due to changes in other weather systems.
KeywordsHigh pressure Anticyclone Australia Trends Rainfall
This project is jointly funded by the Victorian Department of Environment, Land, Water and Planning and the Earth Systems and Climate Change Hub of the Australian Government’s National Environmental Science Programme, and was assisted by resources from the Australian National Computational Infrastructure (NCI). The authors thank Linden Ashcroft, Andrew Marshall and three anonymous reviewers for their comments on earlier versions of the paper. All datasets used are freely available from their respective agencies, and anticyclone data is available for research use by contacting the authors.
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