Issued 6th January 2003
Big dry brings record warm daytime temperatures
Widespread dry conditions during 2002 resulted in one of Australia's driest years on record. It was also one of the warmest. The all-Australian average maximum temperature was the highest on record.
Preliminary data indicate that, for Australia as a whole, 2002 was the fourth driest since 1900. The total annual rainfall averaged over Australia for 2002 was 339mm, well below the long-term average of 472mm. After some useful rain in February, the mean Australian rainfall for the March to December period was the lowest for all equivalent periods on record. Dry conditions were remarkably widespread, with most of the eastern half and the southwest corner of the country recording well below average rainfall for the year.
The low rainfall has been associated with an El Niño event (unusually warm water in the central equatorial Pacific ocean) which developed during Autumn and persisted for the remainder of the year. Such events usually lead to low rainfall over Australia.
The Bureau of Meteorology's National Climate Centre calculates Australia's area-average rainfall from a representative network of around 5000 rainfall stations, most of which are staffed by volunteer observers.
Australian total rainfall (mm) averaged across Australia for each year since 1900.
Rainfall map comparing rainfall during 2002 with the long-term rainfall distribution.
The dry conditions were accompanied by much warmer than normal daytime temperatures. Australia's annual mean maximum temperature was 1.22°C above normal, compared with the previous highest anomaly of +0.91°C in 1980. But despite the high daytime temperatures, reduced cloudiness resulted in overnight temperatures being closer to average with the Australian mean minimum temperature being only 0.01°C below normal. Consequently, the overall Australian annual mean temperature was 0.61°C above the 1961-90 normal, making 2002 Australia's fifth warmest year on record since 1910 (the period for which all-Australian averages are sufficiently reliable for use as a basis for comparison). Almost all of Australia recorded above normal mean temperatures during 2002. Many of the warmest parts of the country were also amongst the driest.
Annual temperature departures from 1961-90 mean (normal) averaged across Australia.
Map of mean temperature anomalies (°C) across Australia during 2002 (departure from the 1961-90 normal).
Australian mean temperatures are calculated from a network of about 110 high-quality, mostly rural, observing stations throughout the country. The temperature records at these sites have been adjusted for artificial discontinuities caused by changes in instrumentation and siting. Many of the sites are included in Australia's Reference Climate Station network - a special network established to monitor long-term climate trends and variability.
Australian temperatures show a general rise during the 20th century, in line with global warming trends indicated by independent records from surface observation networks, weather balloons, satellites and glaciers. According to a preliminary estimate released by the World Meteorological Organization on 17 December 2002, the global mean temperature for 2002 was the second warmest on record (since 1861). Global temperature analyses are made possible through the World Meteorological Organization's free and unrestricted international exchange of climate data from the global observation networks of the World Weather Watch.
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