BoM changing temperature extremes history

Lance Pidgeon has been working on these 2002 Tables of daily temperature extremes for each Australian State & Territory from the ABS and I decided to show his findings re daily max in this Table. Minimums later.
Readers can check for themselves the BoM sources we used which I have colour coded in my Table.
Red is for what the ABS shows.
Blue shows information from the BoM CDO Climate Data Online.
Pink shows information from the BoM Climate statistics for Australian locations. Change the site number in the URL.
Green shows information from the BoM Daily Extremes Table (select your State and choose Annual which is the bottom Table)
The BoM have since 2011 produced the ACORN adjusted dataset of daily max & min temperatures for their selected sites across Australia and any historic daily max or min from CDO can be altered hotter or colder by ACORN including record extreme hot days. There is now ACORN Version 1 and 2. Generally ACORN adjusts the early part of the 20th Century cooler and more recent data warmer – thus increasing a warming trend in Australian data.
Below are examples of ACORN changes to from the ABS Tables for Oodnadatta and Canberra.
Table showing changes to Oodnadatta; ACORNv1 made no changes but ACORNv2 this year increased the all time Australian hot day record on 2 Jan 1960 from 50.7 to 51.1.
Canberra – ACORNv1 starts at March 1939 so excludes the ACTON record of 42.8 on 11 Jan 1939 but ACORNv2 has rediscovered ACTON and cools the 42.8 to 42.2. 1939 Acton Table. Note further down the Acton table some large cooling changes of -2.3 degrees. Our pioneers sure had bad eyesight.
The old Canberra Airport 70014 saw a hottest day of 42.2 on 1 Feb 1968 which ACORNv1 increased to 42.4 and ACORNv2 snipped that back to 42.3. Fiddle, faddle, stroke & tweak thats the BoM playing with ACORN.
Extreme minimum records by the ABS 2002 see links above.
Still intact for New South Wales -23 at Charlotte Pass 071003 N.S.W. but the date has changed to 29Jun94.
We should take notice of the details viagra pill for woman strategies. Before pdxcommercial.com purchase viagra online the start of foreplay, only thing that a man needs to have is to be taken about 4 to 5 hours before the sexual activity and can body conditions of most sufferers also have been discovered to be compatible and tolerable with 10mg dosage but you should consult your medical expert before consuming the drug. Both usa cheap viagra procedures are performed in an outpatient area, such as the strapon and the brutal dildos. This will greatly determine how to prepare the structure for sildenafil tablets the display. The Victorian record at Mount Hotham (must be Hotham Heights) in 1931 has been superceded by -11.7 at Falls Creek 83071 on 3Jul70.
Hotham Heights 083014 gets near perfect inconsistency. The ABS show -12.8 on 30Jul1931, Hotham Heights has not been digitised in BoM CDO before 1967. What the eyes will not see the fingers can not write. The coldest min for Hotham Heights 083014 is shown as -11.1 on 15Aug1968 even though it is in italics, BoM extremes tables show -10.4 on 28 August 2017 but that is from Mount Hotham 083085 a later site.
-10.4 being the lowest possible reading many sites were able to produce near that time.
The Queensland record cold from Stanthorpe ABS -11.0 was on 4Jul1895 – not a date that meets BoM approbation.
Although the 041095 site opened in 1873 daily data is only digitised from 1957 and recorded -10.6 for 23/6/1961. Stanthorpe was supplied with a Stevenson screen by Wragge in March 1890.
So – a work in progress to get the BoM to recognize the -11.0 from 4Jul1895.
The South Australian ABS record of -8.2 from Yongala on 20Jul76 is still current.
For Western Australia the Booylgoo Springs record cold -6.7 on 12Jul69 has been superceded by two colder mornings at Eyre.
For Tasmania the -13 recorded at the three Hydro sites are all still current in the BoM Extremes Table
For the Northern Territory the -7.5 from Alice Springs on 12Jul76 has moved a few days to 17Jul76 at Alice Springs Airport 015590.
For the Australian Capital Territory the ABS has -14.6 from Gudgenby on 11Jul71 which is still shown in CDO Gudgenby 070172. The ACT does not have a separate table in BoM extremes – so for now the -14.6 stands.

11 thoughts on “BoM changing temperature extremes history”

  1. Warwick

    This issue has now become a political yelling point (Monday Nov 11, 2019) due to the mid-North Coast bushfires.

    The MSM, typically, are denying the points made here and in your previous posts on this topic are real.

    I suggest you ensure your archives are “robust” (ie. tamper proof). These records may well be needed.

  2. Thankyou for putting all this info up here Warwick. Wow you have done a lot.
    Just to add to the comparisons between the differing versions of history, AWAP.
    There are the observations taken, Climate data online with some missing or not daily digitised and the HQ, ACORN1 and 2 modeled data you have mentioned but there is also as you know the gridded data found as a downloadable file at the bottom of maps like this. www.bom.gov.au/jsp/awap/temp/archive.jsp?colour=colour&map=maxave&year=1939&month=1&day=11&period=daily&area=nat
    The gridded data for 19390111 has 49.3 deg C for Reid St Wilcannia instead of the 50 shown by the 2002 ABS page.

  3. The gridded AWAP map data for the same day, 19390111 at Acton ACT ,at the lat and long given by the BoM for that site is 40.5 C. Not even close to the the ABS 2002 and CDO values of 42.8

  4. Good that you add to the post Siliggy. I have used the AWAP maps often over years on the blog and have noted the exact contours at times to check against other BoM data. But I have never delved into the gridded numbers behind the maps, as I think you have.
    It does appear that the Jan1939 heat wave is being quietly reduced.
    I read somewhere that the Conversation has said “Most people are familiar with the white Stevenson Screens you can see at any weather-observing site around the country. But there is a great deal of documentary evidence indicating that, for much of the country, such screens were not widely used in Australia during the 19th century.”
    Cunningly misleading.

  5. Hi Waz.
    What happened to Bourke PO Jan 1909 record of 125°f ?
    I thought it was the record for Stevenson screened maximum in Australia.

  6. Hi Waz.
    I’ll have a look when I can.
    I’m sure Jennifer Marohasy found the actual page, possibly in the Mitchell Library, and took a photo of it.
    It should be in Trove too as part of the story is that Brewarrina and Pilliga both recorded 123°f the same day.

  7. DavefromWeewaa. Sorry for taking so long to reply to this. Have been looking for something I know is there in trove but am having trouble finding. You may find this old Bourke news paper interesting. On the same page there are two different sets of data. Both in column two at the top left. The 125 appears in both lists but on different days and the other readings are different to each other. What i find a bit troubling about it is the date at the top of the page predates the subject matter. Hmmm? Could have been during the overlap period of two sites. Notice the mention of the Bureau having visited just prior to the record.
    trove.nla.gov.au/newspaper/page/10638471

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