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Atmospheric Research 79 (2006) 1 – 14 /locate/atmos Geographical and seasonal characteristics of the relationship between lightning ground flash density and rainfall within the continent of Australia E.R. Jayaratnea, Y. Kuleshovb,* a GPO Box 2434, Brisbane, QLD 4001, Australia b Victoria 3001, Australia Received 12 January 2005; accepted 22 March 2005 Abstract Ground-based observations of annual rainfall and lightning incidence collected over periods ranging from 9 to 22 years at 23 stations around the continent of Australia were used to compute values of drain yieldT, defined as the mass of rain produced per lightning ground flash (units: kg f là 1) over a given area of ground. The rain yield was found to vary considerably with geographical location, season and climatic conditions. Of the 23 stations, 5 were mid-continental and these showed a mean rain yield of 2.64 ? 108 kg f là 1 in contrast to the coastal and near- coastal stations that showed a corresponding mean value of 9.91 ? 108 kg f là 1. The difference was statistically significant at the confidence level of 95%. When the stations were classified according to seasonal climate zones, the winter and winter-dominant rainfall stations showed a rain yield of 1.28 ? 109 kg f là 1 while the summer and summer-dominant rainfall stations showed a significantly lower value of 5.44 ? 108 kg f là 1. Again the difference was statistically significant at the 95% confidence level. Every one of the 23 stations showed mean winter rain yields that were significantly higher than the summer values. These differences are attributed to surface heating which controls such parameters as cloud base height and convective available potential energy in the atmosphere. In terms of the behaviour of the rain yield with geographical, seasonal * Corresponding author. Tel.: +613 9669 4896; fax: +613 9669 4760. E-mail address: y.kuleshov@.au (Y. Kuleshov). 0169-8095/$ - see front matter. Crown Copyright D 2005 Published by Elsevier B.V. Al