Climatology of thunderstorms, convective rainfall and dry lightning environments in Australia

• DOI: 10.1007/s00382-020-05167-9
• Publication Date: 2020-02-17T03:02:20Z
• Authors: Andrew J. Dowdy
• Keywords: 13. Climate action; 15. Life on land; 01 natural sciences; 0105 earth and related environmental sciences

The thunderstorm climatology of Australia is examined, including convective rainfall events. Lightning observations are used to train a systematic method for indicating thunderstorm activity, with the method applied to environmental variables obtained from reanalysis data from 1979 to 2016. A range of maps showing seasonal averages in thunderstorm conditions as well as associated rainfall are presented. Long-term climate change trends are also examined, as well as the influence of large-scale drivers such as the El Nino-Southern Oscillation, Indian Ocean Dipole and Southern Annular Mode. Rainfall observations are examined for days on which thunderstorm activity is indicated based on this method, enabling new insight on convection-related rainfall. Low rainfall days are also used to examine the climatology of dry lightning as this is important for understanding the risk of wildfire ignitions. A long-term decrease in thunderstorm activity is indicated for many regions of Australia, as well as some regions of increase. The results also indicate a long-term increase in thunderstorm-related rainfall, noting implications for water availability, design standards and flood risk factors. The findings for northern Australia help provide insight on some aspects of the Australian monsoon, including based on a reduced frequency of days with convective environments as well as indicating an increased intensity of convective rainfall events. An increase in convective rainfall is indicated for both northern and southern Australia, while for non-convective rainfall the results indicate an increase in northern Australia and a decrease in southern Australia. Long-term changes in dry lightning events are also identified, depending on the region and season, noting implications for wildfire management.