This morning (Saturday 23 August) the Weekend Australian published articles by Graham Lloyd, their Environment Editor, on homogenisation practices at the Bureau of Meteorology as questioned by Jennifer Marohasy. As I had a small part to play in bringing this to public light, here is a brief post to bring readers up to date.
The last paragraph in the second article reads:
“And the bureau says an extensive study has found homogeneity adjustments have little impact on national trends and changes in temperature extremes.”
This is laughable. Here is a graph of the national means of Raw and Homogenised minima data from 83 sites (out of 104) that I was able to compare directly. (I also analysed the remaining sites, finding 47% bias, but because large slabs of data had to be left out this is not reliable.)
Fig. 1: Australian mean minimum temperature anomalies 1910-2012
The ‘raw’ trend is +0.63C per 100 years. The adjusted trend is +1.05C. The effect of the homogenisation adjustments is an increase in the national trend of +0.42C or 66.6%. So much for “little impact.”
The article referred mainly to adjustments at Amberley and Rutherglen.
Fig. 2: Amberley minima
According to the BOM, the major adjustment was due to a pronounced discontinuity around 1980, that is, Amberley’s drop in temperature is not reflected in those of neighbouring sites, as is evidently correct.
Fig. 3: Amberley compared with the mean of 5 Acorn neighbours
However, the nearest Acorn site only 50km away, Brisbane Aero, also has a pronounced cooling trend, and a local cooling cannot be discounted.
An adjustment to the raw data before 1980 may be warranted, however, the size of the adjustment is questionable to say the least. The resulting trend at Amberley has now become greater than the trend of adjusted data at every one of the Acorn neighbours, and more than +0.86C greater than their mean.
Fig. 4: Amberley’s adjusted (Acorn) data vs mean of adjusted data at 5 closest Acorn sites
Rutherglen in Victoria again shows cooling turned into warming.
Fig.5: Rutherglen minima
And again, the Acorn adjustments make Rutherglen’s trend greater than every one of its neighbours’ adjusted trends, as well as their mean:
Fig. 6: Rutherglen Acorn vs neighbours’ Acorn (mean)
The BOM is defending its territory, but this latest media exposure will mean increasing and critical scrutiny.
Click for further examples and background.
Tags: Acorn, adjustments, Bureau of Meteorology, Jennifer Marohasy, minimum temperatures
kenskingdom 
August 23, 2014 at 2:58 pm
Great work, Ken. Eventually truth will out.
August 23, 2014 at 5:14 pm
Thanks, Ken. Hold them accountable!
Steve Goddard [Tony Heller] is doing likewise in the US for similar reasons:
http://stevengoddard.wordpress.com/2014/08/22/thermometers-show-that-the-us-has-been-cooling-for-nearly-a-century/
August 23, 2014 at 5:40 pm
Having had a quick look at the above and Jo Nova’s site, as well as having followed this ongoing sad saga, several issues remain unanswered and are alarming.
1. The original raw data should always be kept and made available. Whatever the flaws perceived by the Bureau it is the data as faithfully recorded by many trained observers around the country, and that includes back into the 19th century.
2. The temperatures recorded at one location are just that. At any one moment, even a few or hundreds of kilometers away, could be and probably are different. If the aim of homogenization is to determine a ‘regional’ temperature, then what has been done may be justified and labelled as such. Although claimed to be using peer-reviewed algorithms, have these been published and openly tested? The term ‘correcting for UHI effect’ has been used in connection with this process, but the result appears to be in the wrong direction.
3. Thus if their resulting trends are regional, then they should be published separately as such.
4. Related to this, is a project being supported and advertised by ABC radio, “Ahoy! Old ships’ logs help forecast the future” —
“These days we can find out the temperature anywhere in the world by clicking on our closest device, so why do we need weather observations from over 100 years ago? Kylie Andrews explains how old ship logs can help us predict the future.”
Clement Wragge understood the importance of keeping weather records. …”
The link to the project, the “Weather Detective” is: http://www.weatherdetective.net.au/
Inevitably those collecting ships data, will want to know the land data around Australia at the same time! They will unsurprisingly discover that the 1880s to 1910 period, and particularly the 1890s, were about as warm as the end of the 20th century in many parts of the country. To find more details of these events newspaper stories are easily found on the internet these days.
If the BoM are going to like and believe what is found, they will have to acknowledge the value of and use the pre-1910 data, which is probably more believable than the ACORN adjusted data!
August 23, 2014 at 5:49 pm
Excellent points Paul. “Raw” data are kept at Climate Data Online. Acorn is used to produce regional and national analyses, but the effect should not be to skew the result by 66% nationally.
August 23, 2014 at 6:40 pm
We would be lost without you, Ken. Thank you.
August 23, 2014 at 10:20 pm
This homogenization of real temperature records is a worldwide co-ordinated phenomenon and nothing more than an orchestrated fraud. Steve Goddard/Tony Heller’s Real Science website http://www.stevengoddard.wordpress.com has numerous examples showing that the “warming” trend can be attributed completely to these adjustments, changing cooling or zero trends to warming. Adjustments are even being routinely applied tby NASA/NOAA and others to historical temperature records going back many decades. Others have examples e.g. Paul Holmwood, E.M.Smith (Chiefio). This fraud needs to be recognized and disseminated worldwide in as many media as possible.
August 23, 2014 at 10:20 pm
Something I’ve been curious about is when did these adjustments of past temperatures begin? If this began in just the last fifteen or so years then it’s pretty obvious why it’s being done and would most likely be seen in a court of law to be illegal tampering of evidence to support a foregone conclusion.
A Supreme Court is where this needs to go.
August 24, 2014 at 7:00 am
Ken
You may be able to help me understand a few things.
ACORN has now posted temp data for the first six months of this year. I’m sure that that for 2012 and 2013, data for those years were not posted until early the following year. I believed that the delay may have been for the homogenisation process to have been undertaken.
However, after comparing a few stations with the 2014 data, I find that there is no difference between the raw and the ACORN data. This raises questions about whether the homogenisation process is actually being used or will individual ‘suspect’ raw temps be adjusted at a later date.
Does the BoM use a ‘gridded’ set of data based on ACORN to arrive at average Aust temp or some other method as described here?
http://www.waclimate.net/hottest-day.html
There just seems to be so much confusion as to how the BoM reaches its conclusions.
August 24, 2014 at 8:32 am
When I first posted on this, CDO only had (annual) data for 2012, pending quality assurance. Acorn of course gets the data almost in real time. A few days ago CDO was updated with 2013 data. BOM uses area averaging to create their national averages, but this is flexible!
August 24, 2014 at 9:23 am
Ken,
great work of course.
If I understand this correctly, BOM are saying they significantly adjusted the Amberley data because it showed a pronounced cooling in ca. 1980, whereas the surrounding sites did not.
As the BOM didnt know whether the Amberley cooling was real or not, doesnt this simply amount to the fact that the BOM thought the “Amberley data didn’t look right”?
August 24, 2014 at 10:00 am
When Amberley anomalies are compared with anomalies from neighbouring sites, there is a distinct drop around 1980. Certainly it doesn’t look right. But the adjustment doesn’t look right either. “The operation was a success but the patient died.”
August 28, 2014 at 11:51 am
Ken,
Reading your comment over at Jen’s regarding Karoly & Co pointing out that the adjustments don’t have a significant effect on national trends of ACORN vs RAW, I think I have your argument correct, but wanted to check.
Am I right that you are saying that they indicate the total effect of their adjustments is x% RAW vs FINAL, and that given the total trend is y%, there is very little difference between x and y. However, they adjust certain stations far more than others, and if you look at the effect of their adjustments on a station-by-station basis, there are very large adjustments in certain stations?
August 28, 2014 at 2:40 pm
The BOM says, the national trend in the adjusted data is not largely different from the trend in raw data, but they fail to mention that they raw data they checked was NOT the raw data from those same 104 stations, but different datasets. When the adjusted data is compared with the raw data it is based on (nationally, not station by station), there is a very significant difference in the national trend. There is also a difference station by station of course.
August 29, 2014 at 10:00 am
Thanks Ken. Which leads to the obvious question: what datasets are they using for the comparison?
BTW, great analysis here: https://kenskingdom.wordpress.com/2012/05/14/acorn-sat-a-preliminary-assessment/
Seems very little has changed in the intervening period. I especially like:
There is an approximate balance between positive and negative adjustments for maximum temperature…
I moment of thought shows the obsfucation in such a statement. If I adjust the past down by 0.5C and the present up by the same amount, there is balance across the record, but a 1C increase in trend.
August 29, 2014 at 11:54 am
AWAP and WNDC: Australian Water Availablity Project (700+ stations), and Whole Network Drift Corrected analysis.
August 29, 2014 at 12:46 pm
Amazing! When it comes to climate science, you always have to watch the pea under the cup.
September 2, 2014 at 2:08 am
This manuscript was submitted for publication at ~6:30 am this morning.
Click to access Solar_Energy.pdf
A self-identification process is now in operation:
1. If the 97% consensus community consists of genuine scientists, they will openly address all of the nine pages of precise experimental measurements that disagree with the Standard Solar Model of Hydrogen-filled stars.
2. If the 97% consensus community consists only of phony scientists, they will refuse to address any of the nine pages of precise experimental data that disagree with the Standard Solar Model of Hydrogen-filled stars.