BIG WET PRODUCES COOLEST YEAR SINCE 1984
Media release issued 3rd January 2001
The Director of Meteorology, Dr John Zillman, said today that the total rainfall averaged throughout Australia during 2000 was the second highest since 1900. Preliminary data indicate that the average rainfall recorded for the year was 714mm, second only to 1974 which had an average of 784mm. Much of this heavy rainfall can be attributed to the global climate system having been dominated by La Niña conditions during the early part of the year.
The Bureau of Meteorology's National Climate Centre calculates the average rainfall value from a representative network of over 2000 rainfall stations, which are part of the Bureau's nation-wide network of more than 7000 stations, most of which are operated by volunteers.
Heavy rainfall resulted in the partial filling of Lake Eyre in Autumn and numerous flooding events, such as the New South Wales floods during November. However, most Australians are unlikely to remember 2000 as being particularly wet. The wettest areas were generally those with the lowest populations and most capital cities recorded average or below average rainfall.
Rainfall decile map comparing rainfall during 2000 with long-term rainfall distribution.
The excessively wet conditions experienced throughout much of the country have resulted in low mean temperatures during 2000. The annual mean temperature averaged over Australia was 0.22°C lower than the corresponding mean for the 1961 to 1990 reference period, making 2000 the first cooler than normal year since 1984. The mean maximum temperature was particularly cool, being 0.44°C below normal, while the mean minimum temperature was close to normal.
The Australian average annual mean temperature was calculated from 127 non-urban observing stations throughout Australia. The temperature records at these sites have been adjusted for discontinuities caused by changes due to instrumentation and location. 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.
Notwithstanding the cool year in 2000, temperatures have generally risen in Australia throughout the 20th century. Most of Australia's warmest years on record occurred during the 1980s and 1990s, as shown in the accompanying graph. Global mean temperatures have also risen over the past century. According to preliminary estimates released by the World Meteorological Organization on 19 December 2000, the global mean temperature for 2000 was the fifth warmest on record, with Australia being one of the few regions recording a cooler than average year.
Annual temperature departures from 1961-90 average. Note that good quality temperature records prior to 1910 are too sparse to calculate a reliable all-Australian average.
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