Open Letter from Jennifer Marohasy

Jennifer Marohasy has written to Dr David Jones, head of climate monitoring and predictions at the Bureau of Meteorology, which she has posted as an Open Letter at her blog.

She asked me to review her draft and I made a few small suggestions.

I wish her good luck with Dr Jones.  I am persona non grata with him apparently and I had to write to the Minister before getting a very unsatisfactory reply, many months later, from BOM- Jones refused to reply.  I had to follow up with the Minister again, with a copy to Greg Hunt as Opposition spokesman, before getting some requested information, and an apology.  I analysed this information here.  Promised Journal articles did not arrive at all, and after writing again to the Minister, I received a completely irrelevant paper on ACORN-SAT.  Another letter brought another reply from the next Minister, but still no substantive information I had requested.  This was in August 2012.  My first request for a response from Dr Jones was in July 2010, and my first letter to the Director of Meteorology was in October 2010.  I gave up after this.

I hope Dr Marohasy has more success than I did.

 

Here is her letter:

Open Letter Requesting Verification of 2013 Temperature Record

Posted by jennifer, January 9th, 2014 – under Information.
Tags: 

Dr David Jones
Manager of Climate Monitoring and Predictions
Australian Bureau of Meteorology

Dear Dr Jones

Re: Request Verification of 2013 Temperature Record

I am writing to request information be made publicly available to myself and others so we may have the opportunity to verify the claim made by you on behalf of the Australian Bureau of Meteorology that 2013 was the hottest year on record in Australia. In particular it is claimed that the average temperature was 1.20°C above the long-term average of 21.8°C, breaking the previous record set in 2005 by 0.17°C.

This claim is being extensively quoted, including in a report authored by Professor Will Steffen of the Climate Council, where he calls for the Australian government to commit to further deep reductions in greenhouse gas emissions because of this “record-breaking year”. Accurate climate records are not only of political interest, but are also of importance to those of us who rely on historical temperature data for research purposes. For example, the skill of the medium-term rainfall forecasts detailed in my recent peer-reviewed publications with John Abbot, have been influenced by the reliability of the historical temperature data that we inputted. From a very practical perspective, businesses will adjust their plans and operations based on climate data, and ordinary Australians worry and plan for the future based on anticipated climate trends.

Further, I note that you said in a radio interview on January 3, 2014, following your “hottest year on record” press release that, “We know every place across Australia is getting hotter, and very similarly almost every place on this planet. So, you know, we know it is getting hotter and we know it will continue to get hotter. It’s a reality, and something we will be living with for the rest of this century.”

The Australian Bureau of Meteorology is the custodian of an extensive data network and over a long period now, questions have been asked about the legitimacy of the methodology used to make adjustments to the raw data in the development of the Australian Climate Observations Reference Network – Surface Air Temperatures (ACORN-SAT). Furthermore, questions have been asked about why particular stations that are subject to bias through the Urban Heat Island (UHI) effect continue to be included in ACORN-SAT. In particular why is ‘Melbourne Regional Office’, a station at the corner of Victoria Parade and Latrobe Street (Melbourne CBD) still included in the ACORN-SAT network when this station is known to have become sheltered from previously cooling southerly winds following construction of office towers.

I understand ACORN-SAT was used to calculate the statistics indicating 2013 was the hottest year on record, but it is unclear specifically which stations from this network were used and how data may have been further adjusted in the development of the record breaking temperature anomaly.

Rockhampton-based blogger Ken Stewart, for example, has suggested that in the calculation of the annual average temperature for Australia, the eight sites acknowledged as having anomalous warming due to the UHI would not have been included. Is this the case? I had assumed that the Bureau used all 112 ACORN-SAT locations, and thus that the record hot temperature anomaly announced by you, actually includes a UHI bias.

Radio presenter Michael Smith has given some publicity to claims made by blogger Samuel Gordon-Stewart that the Bureau has overestimated the average Australian temperature by about 4 degrees. Mr Gordon-Stewart calculated average temperatures and temperature anomalies from data from all the weather stations listed by Weatherzone.

Furthermore, given many ACORN-SAT stations have continuous temperature records extending back to the mid-late 1800s and many stations were fitted with Stevenson screens by 1900, why does the Bureau only use data after 1909, all the while claiming that 2013 is the hottest year on record? Indeed it is well documented that the 1890s and early 1900s, years corresponding to the Federation drought, were exceptionally hot.

In summary, given the importance of the historical temperature record, and the claim that 2013 is the hottest year on record, could you please provide details concerning:
1. The specific stations used to calculate this statistic;
2. The specific databases and time intervals used for each of these stations;
3. The history of the use of Stevenson screens at each of these station;
4. How the yearly average temperature is defined; and
5. Clarify what if any interpolation, area weighting, and/or adjustments for UHI bias, may have been applied to the data in the calculation of the annual mean values.

Kind regards

Dr Jennifer Marohasy

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9 Responses to “Open Letter from Jennifer Marohasy”

  1. Ian George Says:

    Ken,
    I am at a loss regarding this as well. I ran the figures from the climate summary for NSW for December and found an interesting anomaly.
    If you average the towns listed for NSW (95 in all), the anomaly comes out at +1.36C (I have only counted those that have a listed anomaly). Yet the NSW and the National anomaly for NSW is recorded at 1.6 and 1.64 respectively.
    As you have suggested in past posts, the BOM seem to be only listing those temps in the ACORN data base.
    And, as we are aware, the ACORN data has been adjusted (mostly downwards).
    This brings into question the idea 2013 was the warmest year and I look forward to what transpires re Dr Marohasy’s request.

    • Ken Stewart Says:

      Area averaging may be the reason. BOM only use Acorn sites for climate analysis- that’s what they say anyway.
      In a climate phase where warming may be plateauing of course you will get record hot years- that doesn’t worry me at all. The BOM has an obsession with extremes apparently, and the introduction of Acorn appears to have removed a number of past extremes from several sites. But the creators of Acorn have shot themselves in the foot with their past adjustments as the record now shows no greater minima warming and no greater winter warming, directly contradicting climate models.

  2. Ian George Says:

    This is OT but couldn’t help to pass this on.
    Another ABC ‘myth’ re drought in Charleville.
    ON ABC local and now posted on Weatherzone:-
    ‘For the past year and a half Charleville has received its lowest rainfall since records began.’
    Facts are:
    June 2012 to Dec 2013 – about 378 mls.
    June 1899 to Dec 1900 – about 290 mls.
    During the Federation drought, there were 6 consecutive years of below average rainfall with 1899 being the lowest on record at 203mls.
    Prior to this drought, 2010-2012 were all above average with 2010 having the second highest rainfall since the 1880s (1133mls).
    How do you get that onto the ABC Watch blog?

  3. wazsah Says:

    Ian, have you got a URL for exactly what weatherzone says – I can not see it there.

  4. wazsah Says:

    Ian, I pulled the monthly data for Charleville PO 44022 from the BoM here –

    http://www.bom.gov.au/climate/data/

    All years from 1881-1959 and a few earlier from 1874.
    It looks as if plenty of 18 month periods from 1 July to 31 Dec had lower than 378mm rain.
    July 1875 to Dec 1876 – 326.8mm but too many 0 months
    July 1898 to Dec 1899 – 266.7mm
    July 1899 to Dec 1900 – 290.3mm
    July 1901 to Dec 1902 – 372.9mm
    July 1928 to Dec 1929 – 314.7mm
    July 1937 to Dec 1938 – 364.7mm
    July 1945 to Dec 1946 – 367.1mm
    Even the BoM decile map here has Charleville plotted outside the “Lowest on Record” contour

    I wonder how this got into the ABC news items in the first place and then did Weatherzone repeat it without checking ?

  5. Ian George Says:

    wazsah
    Here at:

    http://www.weatherzone.com.au/news/reflecting-on-drought-through-song/26363

    And here for the ABC story

    http://www.abc.net.au/news/2014-01-10/jill-mobbs-drought-song/5194614

  6. Ian George Says:

    Thanks waszah
    Now how do you get that info onto ABC News Watch or Fact Finders?
    I also see they’re attacking the ABC (at News Watch) over Canberra’s recent heatwave – Jan 1939 was hotter.
    The Canberra data at ACORN only goes back to March 1939 – very convenient.

  7. Mike R Says:

    Unfortunately the calculations. referred to in Dr Marohasy’s letter above, by Samuel Gordon-Stewart are totally misleading. The difference between his results and the Bureau of Meteorology (-4 degrees C) can be readily reconciled by considering the distribution of stations used for his calculations. His averages included a huge bias towards cooler stations (i.e. in his spreadsheet. the number of Tasmanian sites is approximately the same as that for the Northern territory!. What was Samuel thinking?).

    To his credit Samuel has done a lot of work accruing this data and his link to his spreadsheet at his blog allows others to review and scrutinize his primary data. I wish all the other bloggers purporting to show some novel insight into climate change debate, especially those who criticize the BOM for lack of transparency, would do likewise.

    Samuel has also kindly added my comments at the conclusion of his blog (despite it contradicting his results) that supports the BOM version of the temperature record for 2013. I respect him for this. This corrected version of Samuel’s spreadsheet which significantly reduces the bias is now included in the last comment of the blog entry (see http://samuelgordonstewart.com/wp-content/2013Temperatures-Mick.xlsx).

    This episode illustrates the misunderstandings that can lead to the enduring myths and Machiavellian conspiracy theories that propose that the BOM has manipulated the data either consciously or unconsciously via ‘group think’.

    With respect to ‘group think’, it is incredible that a single determined blogger with, I suspect very little training in scientific data analysis, and armed only with a spreadsheet can produce such a ridiculously large discrepancy of 4 degrees and still be given credibility by Dr Marohasy, . And to think no one else at the bureau, or even those obsessional bloggers who scrutinize every temperature entry, would not have noticed a 4 degree discrepancy? Half a degree maybe, even 1 degree but 4 degrees is pushing things into the realms of fantasy.

    In summary this an example of ‘group think’ or just wishful thinking at it’s worst. Maybe group delusional thinking is a more appropriate description.

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