资源环境科技发展态势分析平台

Australia experienced its driest calendar year on record in 2019. A number of factors contributed to the persistently dry conditions, including a record-low number of cyclones in the Australian region south of 30 degrees S as well as very high numbers of anticyclones during the southern wet season (April-September). The record year is likely a result of natural climate variability together with an underlying trend. The number of cyclones in southern Australia has decreased since 1979, and the number of cool season anticyclones has increased, although large interannual variability means that these trends currently cannot be distinguished from natural variability. However, the longer NCEP1 and JRA55 reanalyses provide evidence of a long-term decline in cyclone frequency in southern Australia since the 1950s.