A reader has asked me to look at how ACORN-SAT has adjusted Cobar temperature data. Cobar is an old site with Post Office data from 1881 – then in 1963 the BoM opened the Cobar Met Office on the north side of town. Map from Google Earth with MO marked by “green X”. Detail of Met Office – note housing adjacent. A Met Office is of course purpose built and staffed by BoM professionals. Then in 1994 an Airport station commenced with an AWS.
ACORN-SAT starts with a positive adjustment to the max of 0.41 prior to 1 Jan 1995. Table of ACORN-SAT adjustments for Cobar. I will start by examining the evidence for that first adjustment 1 Jan 1995. This chart shows Cobar district annual max t data from 1963 – the 3 Cobar station plus Bourke PO and Airport – then Wilcannia and Nyngan. All data from the BoM CDO www site. I have marked the year 1995 with a “green 1” – and the first adjustment to Cobar Met Office is indicated by the “green 2”.
Here is a map of NSW showing all stations used in the various ACORN-SAT adjustments of Cobar. Here is a list of stations used in the first adjustment (1 Jan 1995) – the only one we will discuss at this time.
An important note – BoM ACORN-SAT does NOT use Cobar Airport data, despite the two stations only being about 7km apart and as the chart shows the Airport and MO annual max data are in near lockstep as you would expect.
I am saying this first adjustment is invalid for the following reasons.
[1] The Airport data for 1994 & 1995 closely agrees with Met Office so this fact must override whatever signals the BoM computes from “data mining” at diverse stations up to a few hundred kms away some in very different climate zones.
[2] The Cobar Met Office is a purpose built facility staffed by professionals so that data must be considered a more reliable baseline compared to amateur run sites not owned by the BoM.
[3] If there was a valid reason to adjust Cobar MO data prior to 1 Jan 1995 it is ludicrous to think there would not be a reason revealed in the Met Office admin records.
That is my case that the ACORN-SAT version of Cobar fails at the first hurdle.
There has been much valid criticism of ACORN-SAT in recent months and the entire project must be scrapped.
That the thermometer readings and accuracy at Cobar was well and truly examined in 1966 and if anything found to be reading either spot on or too low is known thanks to Trove.
trove.nla.gov.au/ndp/del/article/142051310?zoomLevel=6
The big question for me is should the death and collapse toll from 1939 be adjusted to match BoM theory past and present? Perhaps a few people could be adjusted back to life.
trove.nla.gov.au/ndp/del/article/82573816?zoomLevel=4
From that “All 49 hotels at Bourke (119 degrees) have practically run out of beer, and there is no hope of supplies being replenished before Thursday.”
Oh and note the 123 Degrees F (another ignored record?)at Collarenebri and the 119 F at Wilcannia. This places Cobar right in the heat!
119 Degrees F is 48.3 Degrees C
123 Degrees F is 50.5 Degrees C
www.bom.gov.au/climate/extreme/records.shtml
Ooops looks like Wilcannia was 114 but with Ivanhoe over 116 (46.7 Degrees C), this still shows the old temps were high around there then.
Even though you desired to only discuss that last bit of dodgy work, it could be the earlier adjustments being incorrect, that has been fudged back a bit by the last one. If the modern reading is correct and that adjustment is incorrect then does that throw all of the previous adjustments out?
A recent conversation with a Cobar District local ( born ~WW2) in the then Mt Hope Hospital revealed an interesting tid bit:- “When she was young ( early 1950s) there was a period of 2 weeks when the maximum temp recorded at the Mt Hope Post Office 160km south of Cobar) from a Stevenson Screen housed thermometer was 114’F.
To be 2 weeks @ 114F sounds a bit suss but perhaps that was the Maximum Graduation of Government issued thermometers at the time.
Further from a local history of Gilgunnia ( 110 km south of Cobar) another oddity turned up:- 29/30 July 1901: 2 inches of snow fell in the district.
This country is ~250 -300m above sea level so that is outstanding!
Given the well known records of the Federation Drought& the multiple deaths from heat exhaustion only a couple of years prior to the snow; one has to wonder at the “Ministry of Truth”/BoM uses to argue the dichotomy between facts/reality & idealism/propaganda.
Somewhere in that grey area exists a pedantic definition of the difference between weather & climate.
Happy Little Taxpayer!
From the BoM Acorn Sat front page:-
“The new data show that Australia has warmed by approximately 1°C since 1910. The warming has occurred mostly since 1950.”
So it would appear to be really handy if you can chuck in a 0.41C right at the time when the AGW debate & the “TV Cooling Tower”images are getting most traction in the public consciousness.
“The warming in Australian temperature data is very similar to that shown in international data and matches very closely warming seen in sea surface temperatures around Australia.”
Me Too, Me Too, Me too ( Sorry, I can’t type foot stamping)
The first thing I notice about the Cobar adjustments is that, apart from those due to merging records, they are all “statistical”.
What this means is that the BOM knows of no reason for any adjustment. Instead it is being produced by comparing the record with other stations, some of them quite distant. Fancy adjusting Cobar on the basis of what’s going on in Sydney, Deniliquin or even Bendigo!
These “statistical” adjustments are based on more or less arbitrary rules for comparing different records. Any change in the thresholds set for making adjustments, or even changes in the order in which these rules are applied, would affect the adjustments arrived at.
It just isn’t a satisfactory method for arriving at long-term climate trends. For a start it is not going to find most of the urban warming that is going on, since this is a general phenomenon affecting a large number of stations at the same time. Comparing the records of those stations is not going to disclose any statistical anomaly that needs rectification through a step adjustment.
The whole approach needs rethinking. Climate trends, if they can be extracted at all from a mass of overlapping records affected by multiple known and unknown factors, need to start by a rigorous selection of records to be included. Only select soundly curated sites. Favour those for which station histories are known, and where those histories indicate few or no changes in the local environment that would affect the temperature readings. Don’t make ANY adjustments for which there is no evidence concerning the site itself.
One day someone will take this approach. In the meantime, expect the number-crunching exercises to get more and more complicated and less and less credible.
I find the Cobar Post office Tmax data to be a major outlier compared to stations nearby, a very anomalous warming trend, the stations nearby cooled over the same period. Since ACORN-SAT fails (almost) entirely to deal with Urban Heating its likely that its version of Cobar has additional problems. In fact, Cobar Post Office data looks it might be a textbook example of Urban Heating.