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For the 7 and 16-month periods ending 30th September 2008
Long and short-term rainfall deficiencies persist
LINKS:
rainfall deficiencies definition
7-month rainfall deficiencies
16-month rainfall deficiencies
Below average September 2008 rainfall over Victoria, southern NSW, SA and the WA interior maintained short and
long-term deficiencies in these areas. In contrast, average to above average September falls over much of the remainder
of the country gave some minor relief to short-term deficits over southwest WA, northeast NSW, southwest NT and Queensland.
It should be noted that only a small amount of rainfall was needed to reduce deficits over southwest NT, as rainfall is climatologically
low at this time of the year for this area.
For the 7-month period from March 2008 to September 2008, areas of serious to severe rainfall
deficiencies have persisted over parts of western Queensland, the NT, southern NSW, central and eastern Victoria, eastern
Tasmania, the SA pastoral districts and most of the WA interior. Above average September rainfall over northern NSW, most
of Queensland, Tasmania, the NT and southwest WA contributed to a reduction in the area of land affected by short-term rainfall
deficiencies in these regions. In particular, severe deficiencies observed in the 6 months ending 31 August 2008 over northeast
NSW and southeast Queensland have eased significantly.
In contrast, below average September rainfall across SA, the interior of WA, Victoria and southern NSW maintained
short-term deficiencies, with some intensification of deficiencies observed in SA. In northern Australia, short-term
deficiencies are generally a result of a poor end to the 2007/2008 wet season, whereas, in southern Australia a
drier than normal 2008 wet season has been the main contributor to deficiencies. Lowest on record
September rainfall
over parts of Victoria, southern NSW, SA and the WA interior has placed severe stress on farming activities in these regions.
Rainfall deficiencies for the 16-month period from June 2007 to September 2008 persist over much of SA, the southern
NT and also in parts of southern WA, far western parts of both Queensland and NSW, western and central Victoria
and northern and eastern Tasmania. The largest area of lowest on record rainfall for the period is in eastern
Tasmania, north of Hobart, with only a couple of small isolated record dry areas elsewhere. The anomalies are
remarkable given that they partly coincide with a La Niña event. La Niña events are usually associated with above average
rainfall rather than widespread rainfall deficiencies. Although some parts of the country saw above average rainfall between
November 2007 and February 2008, months of below average rainfall before and after this period have dominated long-term anomalies.
There were only marginal changes in the areas of long-term deficiencies in September, with a small reduction in area of severe
deficiency over the southwest WA coastal district, but a slight increase in area of the serious deficiency over the WA interior.
The area of severe deficiency over SA and Victoria has slightly increased in size, with a few more isolated lowest on record
areas now evident in SA. Deficiencies also slightly eased in Tasmania, due to above average September rainfall in the region.
The areas of long-term deficiencies generally highlight areas that failed to receive good falls during the 2007 La Niña event,
with large areas of deficiencies through central and southern parts of the country.
The deficiencies discussed above have occurred against a backdrop of decade-long rainfall deficits and record
high temperatures that have severely stressed water supplies in the east and southwest of the country.
The combination of record heat and widespread drought during the past five to ten years over large parts
of southern and eastern Australia is without historical precedent and is, at least partly, a result of climate change.
For more information go to a
Special Climate
Statement on the six years of widespread drought in southern and eastern
Australia, November 2001 to October 2007.
Rainfall
deficiency maps for standard periods out to three years are
available.
Note: The terms used to describe rainfall in these
Drought Statements have the following meanings -
Serious deficiency
- rainfalls in the lowest 10% of historical totals,
but not in the lowest 5%
Severe deficiency
- rainfalls in the lowest 5% of historical totals
Lowest on record
- lowest since at least 1900 when the data analysed begin
Very much below average
- rainfalls in the lowest 10% of historical totals
Below average
- rainfalls in the lowest 30% of historical totals,
but not in the lowest 10%
Average
- rainfalls in the middle 40% of historical totals
Above average
- rainfalls in the highest 30% of historical totals,
but not in the highest 10%
Very much above average
- rainfalls in the highest 10% of historical totals
For more information regarding this rainfall
deficiencies statement, please contact the following
climate meteorologists in the National Climate Centre:
Lynette Bettio on (03) 9669 4165
Blair Trewin on (03) 9669 4623
David Jones on (03) 9669 4085
External Sites Relating to Drought
The Bureau of Meteorology does not make formal drought declarations
as these are done by either the relevant State Governments or by the
Australian Government. The Australian Government Program is called
Exceptional Circumstances
and it is administered by the Federal Department of Agriculture,
Fisheries and Forestry (DAFF). General information about Australian
Government drought assistance is available at
http://www.daff.gov.au/droughtassist.
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