Tropical cyclone trends in the Australian region

Tropical cyclone trends in the Australian region are examined using the Bureau of Meteorology best track data. Here the focus is on analyzing differences in trends between the eastern and western subregions of the Australian formation region, under the assumption that any spurious trends in the best track data due to changes in observational practices would be less noticeable in differences between two adjacent portions. Substantial differences in trends are found between the two subregions, with the number, average maximum intensity, and duration at the severe category intensities of tropical cyclones increasing since 1980 in the west but decreasing (in number) or exhibiting no trend (in intensity, severe category duration) in the east. Analyses of trends in atmospheric variables known to be related to tropical cyclone characteristics also indicate substantial differences between the two subregions.