Soon after the establishment of the Commonwealth Bureau of Meteorology, systems were introduced to monitor the rainfall across the entire country. The Bureau's Monthly Meteorological Report of the Australian Commonwealth commenced publication in January 1910. These reports included, as well as rainfall and temperature information, charts of tracks of anticyclones and cyclones. Patterns of atmospheric circulation have remained an interest (e.g., Karelsky 1956; Leighton and Nowak 1995). Improved communications and upper air data have led to the routine monitoring of global circulation (e.g., Beard 1996). This was not possible in 1910, but annual rainfall maps were published, and the country was divided into meteorological divisions (Taylor 1910). The stations in each division were averaged to produce what we now call district average rainfalls. These district averages are still prepared and used in monitoring and prediction, despite some well-known deficiencies.

Generally good rains during the two decades after the Second World War meant that monitoring of rainfall fluctuations probably seemed less crucial than in earlier, drier years. The re-establishment of drought conditions in the 1960s led the Bureau of Meteorology to establish a drought watch service (Gibbs 1975). Since 1965 official 'drought statements' have been issued by the Bureau whenever such conditions exist. Aggregate rainfall totals are maintained from the beginning of the drought and maps of the extent of the area covered by the tenth and fifth rainfall percentiles, corresponding with 'serious' and 'severe' drought, are issued monthly. These alerts provide an objective assessment of rainfall deficiency, similar to the Goyder Line of the 19th century, and can be used in determining the need for government assistance.

Bureau of Meteorology