Computer simulation of pollution plume originating in Melbourne and flowing over Bass Strait.
Dust, dust and more dust
On September 23 and 24, 2009, New South Wales and Queensland were blanketed by a dust storm originating in the Lake Eyre Basin of central Australia, the source of most seasonal dust storms.
25 September 2009 | Updated 14 October 2011
Atmospheric scientist, Dr Ross Mitchell, from CSIRO Marine and Atmospheric Research, explains how the dust storms occurred and were projected in these forecast animations indicating where and how quickly the dust spread across the continent.
The Australian Air Quality Forecasting System (AAQFS) has been run daily by the Bureau of Meteorology since 2000 and provides forecast guidance for New South Wales, Victoria and South Australia. CSIRO maintains Australia-wide AAQFS in a research mode for fire smoke and wind-blown dust forecasts.
These forecast animations below show the hourly-averaged dust concentration (diameter less than 60 micrometre) as the dust storm develops and spreads.
The 24 hour clock relates to Eastern Australian Standard Time.
23rd - 24th September 2009
24th - 25th September 2009
25th - 26th September 2009
Dr Ross Mitchell on the September dust storms
Dr Ross Mitchell explains what scientists experienced during the severe dust storms of September 2009.
“The pre-frontal dust level was just under 1 000 inverse megametres, and then when the front came through at about 2 pm local time, the reading peaked at 7 200, the highest reading we have ever observed at either station over the last 10 years.”
Dr Ross Mitchell
'We run a couple of monitoring stations in the outback, one at Birdsville and another at a more remote site at Tinga Tingana in the southern Strzelecki desert – about 400 km south of Birdsville. They are both within the Lake Eyre Basin, the main Australian dust source region.
What we have seen over the last 24 hours is really quite unusual. At the Tinga Tingana there was elevated dust through the whole day at a level usually associated with a major dust storm. The units we use in this measurement are ‘inverse mega metres’, and a number of about 1 000 constitutes a really severe dust storm. Normally you will see an event that will peak at this level and then drop back. What we saw yesterday was a signal that remained at about that level for the whole day.
What we saw 400 km further north at Birdsville was even more surprising. The pre-frontal dust level was just under 1 000 inverse megametres, and then when the front came through at about 2 pm local time, the reading peaked at 7 200, the highest reading we have ever observed at either station over the last 10 years.
We have been observing at these places since 1997 and if you look at the 10 years from 1997 to 2007 there was a big change in dust source emission following the 2002 drought. The dust season runs from spring to summer - essentially from September through to March. If you take an average dust level from 2002-2007 and compare that with 1997-2002 there is about a factor of two difference, 2002-07 is about two times higher than the preceding five years, a significant increase on a decadal time scale.
The persistence of this storm is unusual, both the source region and here in Canberra where the dust lingered all day yesterday.'
Find out more about Australian Air Quality Forecasting System.