It is official, last year was the hottest on record in Australia. The following graph from the Bureau of Meterology shows 2005 was exceptionally warm and more than a degree warmer than the 1961-1990 average which is the standard reference period for calculating temperature anomalies.
Many of Australia’s warmest years, including 1988, 1998 and 2002, had temperatures boosted by significant El Nino events. However, 2005 was not an El Nino year, making the high temperatures even more remarkable.
According to the Bureau:
1. Australian temperatures have increased by approximately 0.9C since 1910, consistent with global warming trends.
2. Both daytime and night-time temperatures were high in 2005. The annual mean maximum temperature was 1.21C above average (equal highest), while the mean minimum temperature was 0.97C above average (2nd highest).
3.Temperature anomalies varied throughout the year but autumn 2005 was particularly warm. April had the largest Australian mean monthly temperature anomaly ever recorded, with a monthly anomaly of +2.58C breaking the previous record of +2.32C set in June 1996.
The Bureau noted in its assessment that:
Australian mean temperatures are calculated from a country-wide network of about 100 high-quality, mostly rural, observing stations. The Bureau of Meteorology Research Centre and National Climate Centre have undertaken extensive quality checking to ensure that the temperature records from these sites have not been compromised by changes in site location, exposure or instrumentation over time.
Jennifer Marohasy BSc PhD has worked in industry and government. She is currently researching a novel technique for long-range weather forecasting funded by the B. Macfie Family Foundation.