Wind speeds in the ACT were stronger than usual during the three years 2000–02, as shown in Table 1. The long-term (1961–90) mean annual wind speed at Canberra Airport is 9.3 km/h; in 2000 and 2001 the average wind speed was just over 11 km/h, or approximately 19% higher than normal. In 2002 conditions were particularly windy; the annual average wind speed exceeded the mean by 44.5% and reached 13.5 km/h. These particularly windy conditions coincided with markedly above-average temperatures and below-average rainfall in the region.
|Table 1: Annual wind speed statistics at Canberra Airport ACT, 2000–02|
|Annual average (km/h)||11.1||11.2||13.5|
|Long-term mean (1961–90)||9.3 (calculated from data from 1942 to 2003)|
Monthly average wind speeds at Canberra Airport were above normal in most months during the period January 2000 to June 2003 (Figure 1), increasing particularly from September 2001 and peaking in spring and summer 2002–03. The spring and summer months of all three years show the largest wind speed anomalies; conditions were closer to normal during autumn and winter, although even the winter of 2002 experienced unusually windy conditions.
Figure 1. Monthly wind speed anomalies at Canberra Airport, January 2000 to June 2003 (in km/h).
Of the 42 months in the period January 2000 to June 2003, only two recorded below-average wind speeds. September and October 2002 were the windiest months, with average speeds of 16.9 and 16.8 km/h respectively. The largest wind speed anomaly occurred in June 2002, when the monthly average was 15.3 km/h (6.8 km/h above the long-term mean). In February 2003 the wind speed anomaly was 6.6 km/h. The months with the calmest conditions were April 2000 and July 2001, when wind speeds averaged less than 7.5 km/h
Wind speeds at Canberra Airport show a pattern of above-average annual figures early in the record, followed by a lengthy period of relatively moderate interannual variability, and finally a rapid increase in wind speeds since the mid-1990s.
Figure 2. Annual average wind speed in km/h at Canberra Airport from 1943 to 2002. Note: the long-term (1961-90) average is indicated by the horizontal line through the centre of the graph
- The early to late 1940s were characterised by above-average wind speeds. Thereafter conditions varied about the mean with no apparent pattern until about 1979. The early 1980s experienced above-average wind speeds, followed by a period of below-average speeds from 1985 to 1994.
- Since 1994 wind speeds have increased significantly, with a peak in 1997 followed by a slight decline around 1999–2000. Since then they have continued to rise, reaching a maximum in 2002.
- On average wind speeds have increased nearly 20% since the early 1980s.
The year with the highest average wind speeds was 2002, which recorded a mean of 13.5 km/h (4.2 km/h, or 4.4 standard deviations above normal). The lowest wind speeds were experienced in 1987 and 1993 (7.5 km/h, or 1.8 km/h below normal).
Wind speed fluctuations from year to year do not necessarily occur in a similar way in every season. In Figure 3 the seasonal average values of wind speed at Canberra Airport exhibit different variability through the period of the record.
Figure 3. Seasonal average wind speed at Canberra Airport from 1940 to 2002, in summer (Dec-Feb) and winter (Jun-Aug). Note: values have been standardised using the long-term mean for 1961 to 1990.
- From the start of the record in 1943 until the early 1960s, wind speeds in summer and winter varied differently. There was greater interannual variability in winter than in summer, and the range of fluctuations was also greater in the winter season.
- From approximately 1963 to 1979 wind speeds in the two seasons varied similarly; windier or less windy conditions affected both seasons rather than one
- From 1979 to 1993 there was a tendency for summer and winter wind anomalies to be of opposite sign; windier summers were associated with calmer winters, and vice versa. This was particularly noticeable around 1990, when windier than normal winter conditions and calmer summers persisted for several years.
- Since 1993 both summer and winter wind speeds have increased, but the majority of this change (which is evident in the annual average wind speeds) has occurred in summer rather than winter.
Analysis, graphs and tables by Dr Janette Lindesay, School of Resources, Environment and Society, The Australian National University.
Wind has been measured for an extended period of time at only one official Bureau of Meteorology station in the ACT, located at Canberra Airport. The record there begins in 1942, with the first complete year of observations in 1943. Other organisations (e.g. ACTEW and ACT Parks and Wildlife) may make independent measurements relevant to the area; their data may be made available independently, or through the Bureau of Meteorology. Most of these records are of considerably shorter duration, but often contain invaluable information for otherwise sparsely-monitored areas.
Information on Bureau of Meteorology weather stations and climate data can be obtained from:
|Organisation||National Climate Centre|
|Phone (BH)||(03) 9669 4082|
|Fax||(03) 9669 4515|