1 the australian dry of 2007: causes and outlooks feedgrain partnership drought summit october 30,...
TRANSCRIPT
1
The Australian Dry of 2007: causes and outlooks
FEEDGRAIN PARTNERSHIP DROUGHT SUMMIT
October 30, 2007
Dr. Andrew Watkins (Senior Climatologist)
Dr. David Jones (Head of Climate Analysis)
National Climate Centre, Bureau of Meteorology
Contacts: [email protected]
2
“Typical” Australian Winter/Spring Rainfall during La Niña
Map is the mean rainfall deciles for La Niña years:
1910, 1916, 1917, 1938,1950, 1955, 1956, 1971, 1973, 1975, 1988, 1998
3
June 2007
January-June 2007
Looking Promising…
4
Flooding in eastern Victoria, late June
Flooding in SE Qld, late August
5
July-September 2007
Rainfall
Max Temperature
Murray Darling Basin
But then…
6
The 2007 drought… Rain & Temperature Murray Darling Basin (MDB): Driest September on record: 9.1mm (61-90 average: 35.1mm).
Records back to 1900 ; also 8th warmest max temps since 1950 South Australia: driest June-September on record with only 26.3 mm; also 3rd warmest daytime
(max) temps since 1950, anomaly of +1.4degC MDB, Southern Australia and South Australia (SA) all had their warmest mean January-
September temps on record (anoms: +1.1, +1.0, +1.2). For the MDB, the old record was +0.8 in 1973: record broken by 38%.
New South Wales: 4th driest September on record 8.8 mm; drier Septembers in 1957(driest),1980 and 1928
Grains Research Development Council Southern cropping zones: 5th driest September on record (15.1mm); all 4 drier periods occurred in the first half of last century
MDB: 7th driest July-September (52 mm), only marginally above that of 2002 SA 7th driest September (3.9 mm - last time it was lower was only last year, which was 3rd lowest
3.0mm), also 3rd warmest days and 4th warmest mean Temps Victoria 8th driest September (lowest since 1972) 33mm Australia; 3rd highest maximum (daytime) September temperatures on record (anom +1.9degC),
5th highest mean temps Winter rainfall in the Alpine regions which feed the Murray River, 38.1% below normal; lowest
ever post-El Niño
7
Why the wet then dry???
June
September
warm
too cool
but also too warm to lock in La Nina impacts
and only borderline cool enough
8
Very cold June in the north
June 2007 Maximum Temperature Anomalies
June 20 2007 anomalies
•Cool SST anomaly pattern to the NW was not suggestive of a typical “upwelling” formation
•Most likely due to massive heat flux loss in June’s exceptional northern cold outbreak
9
Current Conditions
•Some warming in the Indian Ocean
•Cool conditions in the “western” Nino regions
•Cloudiness and Trade Winds suggest atmos. playing ball
•Approaching a more classical La Nina event set up
•But… far later in the year than normal
•SOI still neutral
10
International Models
•Virtually all models remain in La Nina (see above) until early 2008, then warm to neutral conditions
•Most (but not all) indicate a warming Indian Ocean (not shown)
11
Seasonal OutlookWinter 2007
Spring 2007
November to January 2007/08
12
Climate Change…
Best estimate (50th percentile) of projected rainfall change (%) for 2030 relative to 1990 under a mid-range emissions (A1B) scenario4. http://www.climatechangeinaustralia.gov.au