Seasonal and latitudinal variations of lightning ground flash activity in Australia

The seasonal and latitudinal variations of lightning ground flash activity in Australia have been analysed using lightning flash counter data. A number of parameters to describe lightning activity such as lightning-days, ground flash occurrence and ground flash frequency have been derived using counter registrations and compared for eigtheen localities across Australia. Lightning activity is the highest in the northern part of the country and it has a clear defined seasonality with sharp increases of lightning-days, ground flash occurrence and ground flash frequency during the wet season months. Lightning activity generally decreases towards the south and seasonal distributions of lightning parameters are more uniform in higher latitudes, but lightning mainly stays a summer phenomenon over Australia. A reduction in lightning ground flash density by a factor of about ten for a 30º change in latitude has been found.