Drought and Rainfall History in Australia
Was 2002 Australia's worst drought ever or
worst drought in 100 years ? Read to see how the truth
is nothing like the myth.
This site started in 2002 in response to alarmist media reporting of the drought that Australia was then experiencing. All sorts of hyped up superlatives, "worst drought ever", "worst drought in a hundred years" etc became commonly used for what was for most of the country, just another damned cyclic El Nino drought. The drought has been blamed on "greenhouse" and we have heard bushfire risk hyped in a similar, unscientific way.
Stunning lack of success by BoM in predicting rainfall 3 months ahead in their "Outlooks"
Following are reviews of rainfall "outlook" forecast
maps against actual results, from Australian Bureau of
Meteorology (BoM) web site. The BoM publish a rainfall outlook every
month for the next three months ahead. So we have these rolling
three month forecasts which are in the left hand column.
Each month they also publish the actual rainfall map for the preceding
three months so I have matched these side by side. Any missing
periods are due to missing maps on the BoM site. Newest
maps on top now. The motivation for this comparison is
to rub in the point that the best climate scientists can not
predict the weather three months ahead yet Australian (and
international) climate scientists purport to predict
the climate three decades and more ahead using Greenhouse climate
models. Similar reviews
of BoM temperature Outlook maps to end 2004 are posted in
8 newsletter found at http://www.warwickhughes.com/climate/
Temperature Outlooks for 2005 are in Coolwire 14.
From winter 2005 the maps are not clickable for a large version. You can see large maps on the BoM website.
|Series of BoM 3 monthly rainfall “Outlooks”
||Rainfall anomalies published by the BoM for
same period as “Outlook” in left panel.
|March 2006 prediction for
to June 06, "50:50 chances for above average June quarter rainfall",
love that 50:50 as the
BoM opts for a dryer southern SA and far W Vic but little
differentiation anywhere alse
||Success for their small area of
predicted dry is offset by total failure in north as wet persists and
failure to predict intense dry areas in SW WA and eastern seaboard.
Small area of success for Pilbara predicted wet.
|February 2006 prediction for March to May 06, "50:50 chances for a wetter than average autumn", as the BoM still goes for that dryer NE and this time a wetter Pilbara.||Huge failure in far north as dry
predict gets rained out. Large failure in NSW, S Qld and the
centre as rains fail where predictions were 50 50.
Intensity of SW WA dry not predicted but Pilbara OK.
|January 2006 prediction for February to April 06, "Reduced seasonal falls in north Queensland", as the BoM opts for a dry NE and wetter S and W.||Dry predict for N Qld is total
failure. WA pretty good. Predicted wet in SA & Vic a 60% win. Dry
result from SE NSW through the centre is a failure as most of those
areas were predicted near 50%. Dry SE Qld is a partial win and the wet
far north was predicted to be dryer than the norm.
|December 2005 prediction for January to March 06, "Mixed rainfall outlook for early 2006", as the BoM opts for three definite predictions.||A minor win in the WA wheatbelt
but larger failure in the wet Pilbara - Gascoyne after predicted less
than 45%. Big failure in far N where predicted dry was swamped by
reality. Partial win for small pale blue area in NE NSW but
overshadowed by broader failure in surrounding dry areas. Tasmania
pretty much dead wrong again. Should have had some
predicted pale grey or yellow.
|November 2005 prediction for December 05 to February 06, "50:50 chances for a wetter than average summer", equivocates the BoM opting for a wet SE.||HUGE area of WA wet was actually
predicted sl drier. SE wet predict turned out drier. Large Qld dry
area predicted sl wetter in the 50 to 55% zone. Just so WRONG,
|October 2005 prediction for
to January 06, "Above average seasonal falls a 50:50 prospect", says
the BoM betting on a wet centre and dry east.
||Wrong by most counts, the
dry E & SE predict turns out average or wet. The HUGE area of
WA wet was not predicted at all. SW Qld dry was not predicted.
Partial success with NT wet but offset by being wrong in the centre and
3 corners region. Tasmania, EXACTLY wrong again.
|September 2005 prediction for
to December 05, "Mixed rainfall outlook for the December quarter", says
the BoM betting on a wet Pilbara - Gascoyne.
||BoM have a win in NE Qld.
(Cheers) but it ends there. Big wet predict in west turns out
average. Major wet in NT, north WA crept up unseen.
Tasmania EXACTLY wrong again.
|August 2005 prediction for September to November 05, "Drier spring for parts of southern Australia", specifies the BoM||Southern Australia was much
wetter than the BoM model. Tasmania EXACTLY wrong again.Another
CLANGER as the BoM totally failed to see the major central to southern
|July 2005 prediction for August to October 05, "Decreased seasonal falls more likely in northeastern Australia", states the pessimsistic BoM||Another complete failure for the
BoM as NE Australia turned out WETTER than average. The vast majority
of Australia turned out much WETTER than the BoM prediction.
Tasmania EXACTLY wrong again.
|June 2005 prediction for July to September 05, "Neutral odds for exceeding average September quarter rain", opines the pessimsistic BoM||Some limited success in SW WA,
Pilbara, and SA-Vic border. The model completely misread the focus of
the standout dry anomaly in the East, which is located in the models
main plus 50% zone. Tasmania EXACTLY wrong again. Overall could not
score more than abourt 40%..
|May 2005 prediction for June to
August 05, "Reduced winter rainfall more likely in parts of southern
Australia", sez the pessimsistic BoM about our main crop planting
||Another big failure for the BoM
prediction as vast areas of Australia incl Tasmania enjoyed average or
rain. Their main little win in SW WA is lessened by the fact that
in the mid 1970's rain there declined about 10% and if the more
realistic average since
1975 was used, there would be much less red and more blue.
|April 2005 predict for May to
July 05, "Wetter season favoured in SE Queensland and northern NSW"
repeats the BoM.
||Good result for the SE Qld / N
predict. However west WA, southern Vic, Tasmania and Cape York, not so
maybe a 55%.
|March 2005 predict for April to
June 05, "Wetter season favoured in SE Queensland and northern NSW".
||Maybe a 55% overall result.
results in SW WA, central WA and Cape York and much of
|Feb 2005 predict for March to
May 05, "Little signal in autumn rainfall odds" stumbles the BoM.
||Plenty signal here. The
prediction is so wrong everywhere. SW WA
wet when predicted dry. Pilbara wet predict less than half correctNorth
NT dry marred by too much rain. Stand feature of the result was huge
dry anomaly from Snowy Mnts. to E Pilbara, not the slightest hint in
the pitiful Outlook.
|Jan 2005 predict for Feb to April 05, "Drier season more likely in north Queensland" says the BoM.||The peak dry event was in SW NT
& NW SA. The predicted peak wet area in Pilbara was in fact
dry. The actual wettest area in SW WA was prdicted
dry. The wet predict for southern SA and far west Vic was
in fact dry. They totally missed the great central band of rain
deficiencies. Overall, say 35% score.
|Dec 2004 predict for Jan to March 2005,
odds for March quarter rainfall” says the BoM
||The broad area of rain deficit sitting east-west
from coast to coast was not hinted at in the prediction, so by this
major criteria the prediction was a failure. However the 55% contour in
SA and Vic turned out a partial success. Some success can also be
claimed for the eastern seaboard 45% prediction. Tasmania EXACTLY wrong.
|Nov 2004 predict for Dec 04 to Feb 2005.
“Generally neutral outlook for summer rainfall” opined the BoM.
||Townsville hinterland dry prediction was 99%
dead wrong. Vast areas of the inland and west had a dry summer, not
hinted at in the BoM prediction. Victoria’s wet summer also not hinted
at in BoM predict.
|Oct 2004 predict for Nov 04 to Jan 2005 “Below
average seasonal falls more likely in parts of eastern Australia"
according to the BoM
||Dead wrong again, VAST areas of eastern
Australia enjoyed average or above average rain. The BoM dry
predict for SE Qld & NE NSW turns out EXACTLY WRONG.
Victorian wet not predicted. Major dry anomaly in centre and Great
Sandy Desert not hinted at.
|Sep 2004 predict for Oct to Dec 2004, "Increased
risk of dry conditions in far southeastern Australia", said the
||Most of "..far southeastern Australia."
was average or wetter; NOT dryer. Partial success with Pilbara wet
predict. West Victorian coast v good but inland Victoria a
failure. North Qld dry predict another furphy. Vast areas
of dry anomalies in centre were predicted in 50 to 55% zone,
|Aug 2004 predict for Sep to Nov 2004 "Dry
Spring more likely in parts of SA, Victoria and NSW", says the BoM
||Although the main predict dry area in SA
coloured brown was actually sl wet or average, the predict for dry in S
SA and W Vic had partial success. The N Qld dry predict was quite good
but the SW Qld wet predict turned out average or dry. The main
dry anomaly in
the NT was predicted sl wet. Dry anomaly in SW and S of WA carried a
predict. The NSW coastal wet anomalies are in a predicted sl dry
zone. Overall, broad failures outweigh the few wins. Tas OK
|Jul 2004 predict for Aug to Oct 04 "Seasonal
rainfall odds close to 50:50", says the BoM. Taxpayers should be asking
what possible use are predictions like this so obviously lacking
any relationship to real world rain patterns.
||NT prominent dry areas predicted sl wetter, WA
dry anomaly in zone predicted to be sl wetter. Broad sl damp predict
for east Aust coastal turns out mainly dryer or average except for NSW
coast strip. Area of sl dry predict centred on NE SA turned out on
av or sl wet. So most major points of the Outlook turned out to
unreliable. Tas Vic OK.
|Jun 2004 predict for July to Sep04
"Increased falls more likely in parts of Qld and WA for September
quarter", says the BoM
||North Qld predicted wet EXACTLY
WRONG. SW corner WA predicted wet also EXACTLY WRONG.
Pilbara to SA actual wet predicted sl dry. Tasmania wrong again.
I am starting to puzzle that pure chance does not more often give
them a win, anywhere.
May 2004 predict for June to August 2004 "Winter rainfall odds mostly neutral", says the BoM
|South Australian wet was actually predicted DRY,
how wrong can they be ? SE Queensland dry actually predicted sl
wet. (Sure, I know it rained there on 1st Sept). Tasmania exactly
wrong again. Even the little predicted dry spot in north WA,
exactly wrong and entire predicted dry belt between N WA through NT
extending to SA and Vic to Tas just so wrong, actually 90% wetter or
|April 2004 for May to July 2004 "Generally
neutral seasonal rainfall odds", says the BoM
||North NSW SE Qld predicted wet exactly wrong.
Tas. wrong again. central Aust huge wet area not hinted at in
|Mar 2004 for Apr to Jun 2004 "Mixed June quarter
rainfall odds in the east and south"
||Large central wet not predicted at all, east NSW
predicted wet exactly wrong. Se Qld dry not predicted. SA
and Vic predicted dry turned out much weaker. West WA
v poor contrary to predicted contours. Tasmania exactly wrong , again.
|Feb 2004 for March to May 2004 "Mostly neutral
autumn rainfall odds, except in WA", says the BoM
||Good result in WA but not covered in glory
January 2004 for February to April 2004 "Neutral seasonal rainfall odds", says the BoM.
|What can I say. Model utterly failed to pick up
major rainfall patterns, poor old Tassie wrong again
December 2003 for January to March 2004 "Neutral odds for March quarter rainfall", says the BoM.
Model fails to predict vast areas of northern and WA wet. The centre is best result. The broad areas of SA, Vic, NSW and Qld turn out EXACTLY WRONG. For SA Vic the predicted 55% chance of wetter conditions turns out to be mainly drier except for a thin coastal strip. NSW divides into two zones separated by a NW / SE line, the SW zone was modelled slightly wetter yet turned out drier while the NE zone was modelled slightly drier but turned out wetter. The broad band of better rainfall from New England NW into Qld was actually modelled to be drier than av. The model also fails to pick up the Cape York rainfall and only the two small pink areas in north Qld could be claimed as success.
For critiques of BoM "Outlooks" prior to
Back to http://www.warwickhughes.com/
Some station rainfall histories to compare.
The worst hit in 2002 in data I have
sighted, all time dryest year.
Central NSW, two Lachlan
Valley stations, annual rainfall 1876-2001 for Condobolin,
Deniliquin near the NSW Victorian border
For Tamworth we have composite data, Curlewis used 1891-1902 then Carroll to 1997, 1998 was fudged from a neighbour then Tamworth takes over from 1999. Tamworth
In Western Australia 2003 saw a bumper wheat crop, we now have Merredin updated through 2003. In vicinity of Newdegate we have Lake Grace, Lake Carmody and Truro all from BoM high quality dataset indicating rainfall history 1906-2003. Apart from 1918 to 1926 in LG and LC which diverge, the three stations are in fair agreement.
The Perth annual rainfall graph 1876 to 2003 shows the 2001-2002 dry conditions in relationship to previous dry periods and it is obvious there have been several dry spells worse than recent years.
Looking at the Perth
graph of monthly rainfall anomalies January 1969 to Dec 2003 we
also see several past droughts worse than the moderately dry winter of
2001. Much is made of the fact that January to March 2004 rainfall has
been negligible in Perth and I have not noticed any informed
spokespeople, state that there is no correlation between rain in these
early months and the annual rainfall, or wet seaon rainfall. So I
am saying it here, in Perth a dry
January-March is no guide to a dry year.
Looking at these two graphs of Perth rain data one would have to wonder why the State Government here is planning to build a desalination plant that would produce water at a cost of three or four times the present supplies from combined dam and underground resources. There is no shortage of the present resource assuming normal prudent engineering to plan for our expanding population. The previous Govt. may have neglected water engineering works in the face of growing demand but the current Govt. takes policy into the surreal. See my Perth Water web site. See new page re cloud seeding.
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Read how CSIRO Chief made incorrect claims re SW WA rainfall data on ABC TV 7.30 ReportTrack all grain and commodity prices
Site updated April 2005 by Warwick Hughes, email comments etc to email@example.com
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