UPDATE: Thanks to a reader who pointed out where to find the 2008 version of BOM rainfall data, I’m able to plot the two data sets. There are differences. See addendum below. – Anthony
BOM loses rainfall
by Tom Quirk on Quadrant Online
Shock Murray-Darling Basin discovery
Analysts at the Australian Bureau of Meteorology have some explaining to do.
In the last two years some 900 mm of rainfall have been removed from the rainfall record of the Murray-Darling Basin. This startling discovery was made by comparing the annual Murray-Darling Basin rainfall reported on the Bureau of Meteorology website in August 2008 and the same report found yesterday.
The annual rainfall figures are shown as reported in October 2010:
Yearly rainfall in the Murray-Darling Basin from 1900 to 2009 as reported in October 2010 with a mean value of 467 mm (solid line).
There is no significant trend in rainfall through this period but there is large variability with rainfall extremes of a 257 mm minimum and a 787 mm maximum.
The comparison with the August 2008 report is revealing. The difference is a decrease of 900 mm rainfall in the 2010 report. The significant decrease occurs after 1948:
Changes to Bureau of Meteorology record of Murray-Darling Basin rainfall. Data downloaded August 2008 and October 2010
The Bureau is already on record adjusting Australian temperature measurements and they now appear to have turned to rainfall, making the last 60 years drier than previously reported.
One can understand that adjustments might be made to a few of the most recent years as records are brought up to date but a delay of forty or fifty years seems a little long.
This raises the question how certain is the data that is used by policy makers?
When we are confronted by apparently definitive forecasts of our future with rising temperatures and less rain, are we living through a period that brings to mind the Polish radio announcement of Soviet times?:
The future is certain only the past is unpredictable.
============================================
WUWT Reader Charlie A writes:
The Wayback machine comes to the rescue!
http://web.archive.org/web/*/http://www.bom.gov.au/web01/ncc/www/cli_chg/timeseries/rain/0112/mdb/latest.txt is the Murray Darling basin annual rainfall archived by archive.org on January 30th, 2008.
The current series can be found at http://www.bom.gov.au/web01/ncc/www/cli_chg/timeseries/rain/0112/mdb/latest.txt
The query form for data and graphs is at http://www.bom.gov.au/cgi-bin/climate/change/timeseries.cgi?graph=rain&area=mdb&season=0112&ave_yr=0
So, now having the older data, I decided to run a quick plot to see the difference. I fired up my Dplot program and came up with this in about a minute:
There are differences in the two data sets. The 2010 data has lower values, starting around 1950, just like the Quadrant article. WUWT?
– Anthony
Addendum: I notice the peaks post 1950 seem to be reduced, but the lows are not. Strange.
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Anthony,
Reur reply comment just above.
Over at Harmless Sky, it declares at the foot of their web pages:
Harmless Sky is powered by WordPress | Using Tiga theme with a bit of Ozh + WP 2.2 / 2.3 Tiga Upgrade
e.g. this thread of over 12,000 comments: http://ccgi.newbery1.plus.com/blog/?p=274&cp=16#comment-89222
Marvellously this not only allows WORDPRESS preview, but easy formatting, AND insertion of images within the comments.
I’m sure that TonyN would be happy to discuss with you. I have his Email address if you want.
There have been massive bouts of political contamination of the meterological and climatological disciplines (and data) in this country over the past 5-10 years to help justify a number of very expensive &/or highly controversial Government policy changes here relating to water (primarily). Each project to date has failed a cost-benefit analysis, however doctored or intentionally mis-interpreted data are used to make a ‘better case’ for a project or policy under the guise of ‘climate change’.
Data and trends are taken out of context by Government (and their self-serving stooges like Steffen, Flannery, Garnaut, Connor and others) to justify their spending of tens of billions of dollars on de-sal plants throughout the country, pipelines from (now full) reservoir to (now full) reservoir, and changes to water allocation policies that now threaten entire agricultural regions.
Climate is used as a ‘tool of fear’ in Australia more than just about anywhere else on the planet. It’s used to sell papers, sell books, approve projects, stop projects, justify public debt, employ thousands in the public sector, target specific sectors of the community, and justify ‘white elephant’ infrastructure.
‘Climate change’ is a politicians (and social engineers like the Greens) greatest weapon.
What pathetic sceptic drivel – a full apology is in order from Mr Watts. You’ll publish anything Anthony.
• The Bureau of Meteorology updated its spatial analyses in 2009 as part of the Australian Water Availability Project (further details on the Bureau’s component can be found here (http://www.bom.gov.au/amm/docs/2009/jones.pdf). The new data are at a much higher resolution (~5km versus ~25km previously) and substantially more accurate. The analyses are described in a scientific paper (above), and draw on a partnership between Bureau of Rural Sciences, CSIRO, Australian National University and the Bureau of Meteorology.
• A large area average (such as for the Murray-Darling Basin) is not a measurable quantity but rather is estimated from discrete values at stations. The estimate has most recently been improved by improving the quality of the underling algorithms used to convert station rainfall to gridded rainfall. The process of improving data and estimates is ongoing, through the use of new data (such as from satellites/radar), back digitisation of historical rainfall data and improvement to spatial analysis algorithms.
• The difference between the old (Barnes) and new (Australian Water Availability) analyses is typically 0 to 5% by year – the mean difference is 1.8%. The newer analyses are very slightly drier overall than the Barnes analyses, in part, because earlier versions of the analyses tended to spread rainfall too widely from alpine/high altitude stations because they did not account for altitude. In both cases the linear trend in the area average Murray-Darling Basin rainfall data is for a very slight (non-significant) increase of rainfall over the last 110 years
• A description of the data and methodology has been available publicly at http://www.bom.gov.au/climate/change/about/rain_timeseries.shtml
Will Tom Quirk make an unreserved apology !?
Re: Fool me once … October 18, 2010 at 12:47 am
It might have been more helpful and politic if you had referred us directly to the following paper:
High-quality spatial climate data-sets for Australia.
David A. Jones, William Wang and Robert Fawcett (2009)
http://www.bom.gov.au/amm/docs/2009/jones.pdf
However, upon a quick read, it does not seem to me to explain the step change discussed in the lead article here.
The Jones paper in fact shows rainfall data per AWAP method all the way from 1900 to 2007, not from ~1950 to 2009, that being the suspected period of step change.
See Fig. 11(b) and also the text below it, talking of AWAP data from 1900.
I also don’t see that this change in itself is important, since it has only a slight effect on trends. However, it is interesting in the light of “adjustments” in other data sets, all in the “it’s worse than we thought” direction. For instance the recent NIWA episode.
Of course some of the “adjustments” have been in gradual steps over a lengthy period, which is an interesting consideration, wot?
Farmonline – 19 Aug, 2009
“Murray chief goes against the climate flow
As speculation grows that consecutive years of dry conditions could be a permanent climate “step change”, Murray-Darling Basin Authority chief Rob Freeman has expressed confidence that wetter times will return………..”Some commentators say this is the new future, I think that is an extreme position and probably a position that’s not helpful to take,” he said.”
20 Aug, 2010: Federal election results in hung parliament. Labor retains government with help of Greens……
ABC News – 18 Oct, 2010
“For Murray Darling Basin Authority chairman Mike Taylor, the week was mission near impossible. He delivered dire news to dozens of inland communities, in short telling them that they are living well beyond their means. Their water use must be drastically cut, in some cases by almost a half…..”
I see very little to get exited about BobFJ – number of stations change dramatically after 1950 – depends on where those stations are related to orographic effects in the new spatial analysis and amounts of rain in what part of the state in what years. The whole issue is a massive beat-up.
But as always one could get all the rainfall data from BoM’s database ADAM and do your own spatial analysis and publish it.
Fool me once Reur October 20, 2010 at 1:06 am
See: Fig. 1 (a) in the David Jones et al paper:
http://www.bom.gov.au/amm/docs/2009/jones.pdf
The number of rainfall stations plotted do not exhibit a step-change from ~1950 to 2009, which is the primary subject in the lead article here. There is a notable peak between ~1960 & ~1980, but it then drops away to a rough fit to a gradual linear increase from ~1915 to end. ( From around 5,400 to 6,600 stations)
The AWAP change to spatial gridding is applied to all data from 1900 to 2007.
Anthony’s comment at the foot of the lead article is also succinctly relevant:
Addendum: I notice the peaks post 1950 seem to be reduced, but the lows are not. Strange.
I agree that there is very little to get excited about because the step-change is small, but we will have to wait and see if it suffers from “creep” like as for example with the anti-clockwise rotation of GISSTEMP. As I said, it is strange how the cumulative “adjustments” of various surface station data are always in the “it’s worse than we thought” direction.
I’m wondering if Quadrantonline has gone offline, or if it’s being filtered by the NZ firewall?