A Law Unto Themselves: The Australian Bureau of Meteorology

Sunday, 12th November 2017 – 4PM

Honourable Josh Frydenberg MP
Minister for Environment and Energy

Dear Minister

Re: Suspend announcement of new record hot days – Inform WMO that Bureau’s measurements are currently not comparable with mercury thermometers – Give directive for release of more A8 forms – Establish an audit mechanism


I write to confirm my receipt of some preliminary information from Mildura – you may remember that I wrote to you on 26th September suggesting that the new record hot day for Mildura announced by the Bureau of Meteorology of 37.7 degrees Celsius recorded on Saturday 23rd September, was unlikely to be a valid record because it was not measured consistent with calibration.

The Bureau have since acknowledged that their method of recording temperatures from electronic sensors is not accredited, though they claim it nevertheless gives readings equivalent to mercury thermometers. Interestingly, your office emailed a journalist, backing them up – claiming that a single electronic sensor can “mirror the behaviour of liquid in glass thermometers”. This is nonsense, because mercury and alcohol thermometers have different time constants. This is one reason the World Meteorological Organisation (WMO) insist on numerical averaging: alcohol thermometers (that measure temperature minima) have longer time constants than mercury thermometers (that measure temperature maxima).

Historically, alcohol thermometers were used to measure minimum temperatures, and mercury thermometers were used to measure maximum temperatures – across Australia. Then on 1 November 1996, the Bureau changed their ‘primary instrument’ to electronic sensors.

Anyway, I am grateful for the information recently received from the Bureau (following your directive), which does enable some comparison of measurements from a mercury thermometer with measurements from an electronic sensor, but only for Mildura for the period November 1996 to December 2000. I received this information in the form of over 4,000 scanned A8 forms, and have personally transcribed much of the relevant information, specifically the handwritten manual recording from the mercury thermometers.


I can confirm, that the values recorded manually on the A8 forms from the mercury thermometers for the period November 1996 to December 2000 are significantly different from the official values recorded from the electronic sensors. If we consider just the values for September, the mean difference is statistically significant at the 0.05 level of probability, and is +0.34 °C, +0.27 °C and +0.28 °C for the years 1997, 1998 and 1999, respectively.

Somewhat surprisingly, the automatic weather stations at Mildura for these three Septembers recorded statistically significantly cooler temperatures than the mercury thermometers. (This is generally consistent with other values on the A8 forms, though winter and summer differences may be more extreme.)

This could suggest that the recent record hot day was in fact an underestimation of temperature. However, I’ve since been shown photographs that prove the electronic sensor in place at Mildura for those three years (1997, 1998, 1999) was shorter and thicker (with a correspondingly significantly longer time constant), than the Rosemount sensor that was in place on 23rd September 2017. Furthermore, the Bureau’s own documentation indicates that the Stevenson screen size has also changed – introducing yet another variable. Additionally, it has been brought to my attention that at that time – back in 1997, 1998 and 1999 – the official recorded temperatures were likely to be a numerical average taken over at least one-minute. The recent record was a one second-spot reading. I have confirmed this from the one-minute data for Mildura for 23rd September, also made available to me recently – following your directive.

While the current head, Andrew Johnson, claims the Bureau has always taken one-second readings from electronic sensors, this is at odds with a letter from Sue Barrell, Bureau of Meteorology, to Dr Peter Cornish dated 6th February 2013, available online here. The letter details a methodology much more consistent with World Meteorological Guidelines – specifically reference is made to numerical averaging.

The bottom line is that since the introduction of automatic weather stations over 20 years ago, there has been no documented standard against which Australian temperatures at Mildura, or anywhere else, have been recorded. Of most concern to me is the muddling, (including by your staffers), of the numerical averaging-period with the time constant. The Bureau somewhat confusingly often refers to the time constant as the sensor “averages”.


I have been reliably informed that when the various variables for Mildura are eventually determined – as they must – the actual hottest day on record for September for Mildura may be 22nd September 2003 or the 28th of September 1928 if temperatures before 1910 are ignored.

Interestingly, the hottest day ever for Mildura according to the official ACORN-SAT record is 10th January 1939; that summer of 1938-39 was exceptionally hot across south-eastern Australia. When I was researching the longer historical temperature record for Mildura a couple of years ago (at the same time I was correcting for Stevenson screen installations and moves from the post office to the airport in back-of-the-envelope type calculations), I determined that the hottest summer on record at Mildura was likely 1905/1906.

Backing this up, a relatively recent study published by Lucinda Coates and colleagues (Environmental Science and Policy, Volume 42, 2014) identified Januaries in 1879, 1896, 1906 and 1908 as being months with ‘significant heat events’ in Australia.

Our Bureau ignores this early pre-1910 historical temperature record, and after 1910 corrects for its political incorrectness through homogenisation as I have detailed elsewhere.


Whilst the historical temperature record issued by the Bureau may have only been of limited, or academic interest, in the past this is no longer the case in view of the current scientific and public policy debate about global warming. These temperature recordings are now the primary input data which determine a range of scientific predictions, projections and model outputs with enormous, fiscal, economic and political implications both for Australia and internationally. If these temperature recordings are wrong then all the consequent scientific, fiscal, economic and political decisions based on this data may be wrong also.

On this basis, given the importance of the temperature record, I would suggest that there needs to be an ongoing and independent oversight audit mechanism/group established to ensure that you and the government can be confident that you are receiving reliable and accurate temperature records on which to base government policy decisions both nationally and internationally.

The fiscal records of government agencies are independently and regularly audited for amounts far less than the fiscal and economic impacts of global warming policies so it would seem only prudent and reasonable that the temperature records of the Bureau of Meteorology, which have such huge fiscal and economic impacts, should be subject to a similar audit regime to ensure their accuracy, integrity and reliability.

Historical temperature records back to 1880 are the primary input data which determine the range of scientific predictions, projections and model output with enormous fiscal, economic and political implications both for Australia and internationally.

Current and historical temperature records for Mildura, as measured and collated by the Bureau, are included in the calculation of global temperatures by the UK Meteorological office and NASA – subsequently relied upon by the United Nations Intergovernmental Panel on Climate Change informing the Paris Accord.

Perhaps unbeknownst to these organisations, our Bureau has a ‘novel’ method of recording temperatures from electronic sensors in automatic weather stations that cannot logically give readings consistent with the liquid-in-glass thermometers, which were the primary instruments for Australian temperature measurements until 1 November 1996.


Given the importance of the temperature record being correct: there is a need for an ongoing and independent oversight audit.

Inform the WMO that the temperatures recorded by our Bureau are not consistent with calibration, nor any international standard.

Direct the Bureau to desist from announcing new record hot days – not only for Mildura but for all 563 automatic weather stations recording surface temperatures across Australia.

Also, I would be grateful to receive more scanned A8 forms, specifically for the period 1 January 2001 until 30 September 2017 for Mildura. (It could be that I have only received A8 forms for Mildura until December 2000, as the Bureau is awaiting your directive to release the forms after this date.) I also await advice regarding the availability of scanned A8 forms from the other 38 locations with parallel data, as I detailed in my letter to you of 22nd October 2017.

Yours sincerely

Jennifer Marohasy BSc PhD
Senior Fellow, Institute of Public Affairs
Founder, Climate Modelling Laboratory, Noosa
Member, International AltMet Network

The assistance of AltMet Network members LP, KS, JV, MN, PC, PM and RM is gratefully acknowledged in the drafting of this letter.

31 Responses to A Law Unto Themselves: The Australian Bureau of Meteorology

  1. Dave Vought November 13, 2017 at 8:47 am #

    Excellent work again Jennifer.
    The time and effort you put in to get the truth of what’s been going on with the temperature records now and in the past is much appreciated.
    I hope we get an audit, and the A8 forms.
    Regards Dave

  2. Cloudbase November 13, 2017 at 9:24 am #

    Love it Jen. Keep at them.
    If you ever need help transcribing data….if they ever release more damming evidence ;-)…I’d be happy to help.

  3. cohenite November 13, 2017 at 10:09 am #

    Great work Jennifer. Who apart from yourself would you like to be on any independent audit body?

  4. Bob Fernley-Jones November 13, 2017 at 11:28 am #


    Melbourne Regional Office had two small screens for some time before being closed down because of various site problems including extreme wind turbulence from tall buildings plus only metres away, multi-lane road traffic variability on two sides and expansive tarmac. I think it was effectively Head Office, so it seems likely there should have been parallel instrument testing there. If there is any place where sudden changes can occur it is there and it would be very interesting to see any cross calibrations for sudden events. The anemometer was decommissioned a long time ago (using airport since) and temperatures can drop 10 degrees quite suddenly with wind reversals north to south

  5. spangled drongo November 13, 2017 at 11:30 am #

    Thanks for all your tremendous efforts, Jen.

    How can a govt that proclaims to be trying to account for unnecessary expenditure NOT agree with what you are requesting?

    And after that, they need to support a detailed audit of the world’s long term tide gauges to compare vertical movement at those sites.

    Without these audits we are simply wasting taxpayer’s money and generating fake science.

  6. William Taylor November 13, 2017 at 2:58 pm #

    More great work, Jennifer. Thanks again from America.

  7. Alf Cristaudo November 13, 2017 at 5:22 pm #

    It’s scary the lengths some people/organisations will go to influence government policy settings.
    It is outrageous misrepresentation at the highest levels with unbelievable consequences!!
    Congrats Jen, keep going👍

  8. Geoffrey Williams November 13, 2017 at 6:54 pm #

    Great work again Jennifer. We are all behind you and support your argument.
    Australian science is greatly indebted to you.
    Very best regards
    Geoffrey Williams

  9. James Doogue November 13, 2017 at 8:41 pm #

    Like pulling teeth!

  10. Debbie November 13, 2017 at 8:42 pm #

    Good for you Jen.
    They’re clearly marking their own homework.

  11. Simon Kelly November 14, 2017 at 12:19 am #

    Hi Jennifer. I also am prepared to assist with transcription of paper scans. I have moved from disappointment in BOM to exasperation. The problem with BOM is this. The water cooler discussions in BOM are not “how can we improve our data capture?”, it is “how can we persuade people of the perils of global warming?”.

  12. A C Osborn November 14, 2017 at 1:10 am #

    The fact that when introduced the Electronic Sensors were reading lower is consistent with a report I saw some years ago. However there were other reports from the Snow measuring sites in the USA that suggested their ones were reading much higher.
    Is there any way to compare the readings that you have from the forms with the values output by the BOM and used for purposes of calculating the Global average?

    ps Thanks for hard work.

  13. Idiot_Wind November 14, 2017 at 3:27 am #

    Very well done, Jennifer. I hope you receive the additional information you requested in order to continue the good work.

    1. For other countries, is it known if and when there were changes to the temperature reading technologies (e.g. replacing liquid-in-glass with electronic sensors) and over what period the changes were effected?

    2. As A.C. Osborn has indicated, it will be important to establish (if such is possible!) whether electronic sensors systematically read higher or lower than liquid-in-glass ones. If it turns out that, say, the temperature difference all depends upon the sensor make/manufacture or something equally difficult to adjust for then it will be very serious for the data sets; it will NOT be possible to compare the later readings with the earlier ones. We will NOT be able to tell warming from cooling over the period of technology change over.


  14. Reed Coray November 14, 2017 at 4:43 am #


    Thanks for your efforts to rein in the BOM.

    There are two questions I would like someone in your position to formally ask the BOM.

    (1) Why don’t you, the BOM, make all Australian temperature data available to the Australian public?

    (2) What are you afraid of?

    I think I know the BOM’s answer to the second question. Specifically, “We are ‘afraid’ that someone with a political agenda will torture the temperature data in a way that supports their political aims; and it will require a massive effort on our part to undo the damage. This is a legitimate concern to us because it parallels how we have treated Australian temperature data.”

  15. Robber November 14, 2017 at 6:33 am #

    Excellent work – keep searching for the truth through logical analysis. Reach out of you need some crowdsourcing to do the analysis.

  16. John in Oz November 14, 2017 at 7:19 am #

    Ian George,

    Your link shows 1906 but is still a shocker for a long period of extremely high temps.

    I also looked at 1905 to see if Dec was a hot lead-in to 1906. Worth looking at as it was also a very hot summer and there were even 30+ days in May

  17. Mark McD November 14, 2017 at 9:28 am #

    Great to see them being held to standards of which they are clearly unaware.

    I pretty much gave up on trusting the BoM after the 2009 Vic fires. Just prior to them we had 4 days of ‘record’ temps above 43ºC. This was trumpeted widely and a max of 47.3º was touted.

    Those 4 days became 3 days with the 1st of them magically transforming to 36.4º – How many of you remember the 4 days? Hacve a look now – they disappeared one of them.

    On top of that, we were told (from memory) “the hottest day in 100 years” and “the hottest 4 days in 105 years” (year year numbers might be reversed there. 😀

    Now being a bit of an odd character my first thought was… ‘so there was a hotter day 100 years back and 4 hotter days 105 years back.

    Of course with all the data fiddling it’s not impossible to check records.

    One suggestion – I think their enough aggro out in the community for you to set up a petition to put pressure on the BoM and the Minister. We NEED that audit because as the previous Minister said, ‘we need to be able to trust the BoM’

    He said it as a reason NOT to audit the BoM but I have pro-AGW friends who were immediately suspicious. Trust issues are a reason to DO the audit of them, not to walk away from an area of concern.

    I am sure many who visit here would be happy to promote a petition – with so many BS ones being run it would be good to see one based in the real universe. 😀

  18. Mark McD November 14, 2017 at 9:30 am #

    EDIT: (Is there a way to do that?)

    “Of course with all the data fiddling it’s not impossible to check records” should be

    “Of course with all the data fiddling it’s now impossible to check records.”

  19. Jennifer November 14, 2017 at 1:10 pm #

    Thanks everyone for your comments.

    A few comments in response:

    Mark McD,

    I like your idea of a petition. But I simply don’t have the time. If you know someone who does, and has some experience at this… and also fundraising?

    Bob F-J,

    Yes, Wow! And it would be great if you could make an FOI request to the BOM for the parallel data for Melbourne.


    We need the parallel data for the 38 locations for which this is available. But I don’t know how to get it. The few years for the one location that I am reporting on here… well, it was a lot of effort, and a little luck, getting this.

    If you could press the issue… perhaps with your local MP?


    I would really like to be part of an audit group – and thanks for the vote of confidence.

    AC Osborn,

    The values on the A8 forms (summarized here for three Septembers) can be compared with the CDO values (official Australian ‘raw’ values) and then the UK Met office values, NASA values and so on… because Mildura is one of those locations that is incorporated into the international databases, and most of these are available as individual series. It just takes time to do. At some point I want to write all this up for publication, and then this will probably be done.

    Meanwhile, Jo Nova has blogged on the same here: http://joannenova.com.au/2017/11/finally-bom-releases-some-secret-comparison-data-a-snow-job-revealing-new-thermometers-not-comparable/

  20. Alan R November 15, 2017 at 1:46 pm #

    What I don’t get is how people accept that putting rubbish and pollutants into the water has a catastrophic effect, yet refuse / fail to acknowledge that putting pollutants into the atmosphere has the same catastrophic effect. End result is that the Jennifers of this world run around sweating the small stuff, claiming a temperature reading here and there is inaccurate while ignoring the big picture. Jennifer, knock yourself out – and go tell the people of air-polluted Beijing or Delhi that someone mistook a temperature reading by a few degrees.

  21. hunter November 15, 2017 at 8:24 pm #

    This is wonderful progress.
    Please keep upvrge good work.

  22. Crowbar November 15, 2017 at 10:13 pm #

    Ian George, that link to BOM gives me “Weather Data Temporarily Unavailable”

  23. hunter November 16, 2017 at 1:20 am #

    This is important progress.
    Please keep up the good work….

  24. Steven Fraser November 18, 2017 at 4:01 am #

    Outstanding progress, Jennifer. Kudos to you and your associates.

  25. Rob Warren November 18, 2017 at 12:46 pm #

    Yes Both of Ian web pages are Temp unavailable!
    I wonder if there deliberately unavailable

  26. Cloudbase November 18, 2017 at 3:05 pm #

    I’d like to know why they just dont use digital cameras and imaging software to read the alcohol and mercury thermometers. Then there would be no reason to make adjustments to make the data comparable….and the time averaging problem is also a non issue.

  27. Ian Thomson November 25, 2017 at 8:42 am #

    Hi Cloudbase, they don’t because that wouldn’t give the result they want. Accuracy is not the end game, getting results that fit the theory is it.

  28. Neville November 25, 2017 at 4:28 pm #

    Here’s an uncontaminated data-set that started in 1958 and is much more accurate than all the other surface based data and only shows about 0.1c a decade of warming. What’s not to like and why should we be wasting endless trillions $ on a non problem for a guaranteed zero return?
    Even the alarmist’s hero Dr Hansen called Paris COP 21 just BS and fra-d, so why should anyone give them the time of day?

    Thanks to Dr Patrick Michaels and Dr Ryan Maue.


  29. Robber November 28, 2017 at 7:10 am #

    Any response from Josh or BoM?

Website by 46digital