Data manipulation enhances “climate change” in Australia

This blogpost comes from articles by the Australian biologist Dr Jennifer Marohasy. The previous post, “There is no climate crisis in Australia”, also came from Dr Marohasy.

It could be that the last 26-years of temperature recordings by the Australian Bureau of Meteorology (BOM) will be found not fit for purpose and will eventually need to be discarded. This would make for a rather large hole in the calculation of global warming – given the size of Australia.

The Australian BOM undertakes industrial-scale remodelling of historic temperatures in ways that generate more global warming for the same weather through the process of homogenization. The process is neither transparent nor scientific and lacks consistency with the Bureau’s own policies. Also of concern, since 1996 the Bureau has converted to custom-made electronic probes for temperature recording, and rather than averaging temperatures over one or five minutes as is standard practice around the world from such equipment, the Australian Bureau is recording one second extrema. To be clear a ‘hottest temperature’ record is now a one second automatic download from a supersensitive electronic probe rather than a reading from a more inert mercury thermometer. [The BOM say the response time of its probes means the recorded measurement is effectively an average of the temperature over the previous 40-80 seconds]. This is another way the Bureau gets more global warming for the same weather – with its own third generation probes.

Theoretically the probes would also bias the minima downwards, except remember Thredbo? How I showed a few years ago that the Bureau has placed limits on how cold an individual weather station can record temperatures, so most of the bias is going to be warmer.

Very few people realise – though I have explained all of this multiple times including to multiple journalists – that when the BOM transitioned in 2011 to the new Australian Climate Observation Reference Network – Surface Air Temperatures (ACORN-SAT) system for calculating the national average temperature it removed 57 stations from its calculations, replacing them with 36 on-average hotter stations. This had the effect of increasing the recorded Australian average temperature by 0.42 degree Celsius, independently of any actual change in the weather.

Of the 57 stations removed from the calculation of the national average temperature, only 3 of these had closed as weather stations.

There are so many problems with Australia’s official temperature record including the changing combination of stations, the use of custom-designed probes without averaging, not to mention all the homogenization.

Remember Rutherglen

Australia has reliable historical temperature data for the period from about 1889 until 1996 measured using liquid-in-glass thermometers – mercury for maxima and alcohol for minima. Averaging the maxima and minima gives a mean temperature. In some of the records there is a cooling trend to about 1960, and then warming to the present. This is particularly the case at inland locations. Within the longer trend there are short cycles with temperatures generally trending up during drought, and down during wetter years.

When the longest continuous temperature series are combined, with a transparent system of area weighting, the overall warming trend is only 0.3 degrees Celsius per century (1887 – 2013). This is significantly less than the Australian BOM 0.7 degrees Celsius for the same region but a shorter period (1910 – 2016). NASA recently announced a rate of 1.1 degrees Celsius since the late 19th century average, the start of the industrial revolution.

The daily maximum and minimum values in ‘the national temperature dataset’ (the homogenized ACORN-SAT data) are different from the actual recorded historical values, often by several degrees, usually cooler. The further back you go in time, the more significant the cooling thus making what was a modest temperature increase over the period appear greater than it is.

This remodelling is in a different category to correcting for outliers that might have been caused by transcription errors or faulty equipment. The remodelling cannot be confused with legitimate data-hygiene/quality assurance.

Furthermore since 1996, at an increasing number of weather stations platinum electronic probes have replaced the traditional mercury and alcohol thermometers. For example, the Rutherglen agricultural research station has a long, continuous, temperature record with minimum and maximum temperatures first recorded using standard and calibrated equipment in a Stevenson Screen back in November 1912. Considering the first 85 years of summer temperatures – unadjusted/not homogenized – the very hottest summer on record at Rutherglen is the summer of 1938/1939.

At Rutherglen, the first significant equipment change happened on 29 January 1998. That is when the mercury and alcohol thermometers were replaced with an electronic probe – custom built to the Australian Bureau of Meteorology’s own standard, with the specifications still yet to be made public.

According to Bureau policy, when such a major equipment change occurs there should be at least three years (preferably five) of overlapping/parallel temperature recordings. However, the mercury and alcohol thermometers (used to measure maximum and minimum temperatures, respectively) were removed on the same day the custom-built probe was placed into the Stevenson screen at Rutherglen, in direct contravention of this policy.

In 2011, the Bureau made further changes in that it stopped averaging one-second readings from the probe at Rutherglen over one minute. The maximum temperature as recorded each day at Rutherglen is now the highest one-second spot reading from the custom-built probe. That is correct – a spot reading. Whereas the standard practice is to average temperature over one-minute in the UK and over over 5-minutes in the US!

So, to reiterate, we now have a non-standard method of measuring (spot readings) from non-standard equipment (custom-built probes) making it impossible to establish the equivalence of recent temperatures from Rutherglen with historical data.

At Rutherglen, a modest rate of warming in the historical maximum temperatures of 0.7 degrees Celsius per century was changed to 1.3 degrees Celsius in ACORN-SAT Version 2. Changes to the minimum temperature trend are more dramatic: a slight cooling trend of 0.3 degrees Celsius in the historic dataset was changed to warming of 1.9 degrees in ACORN-SAT Version 2 for Rutherglen.

There is much more detail here concerning temperatures at Rutherglen and surrounding stations.

Remember Thredbo

The number of weather stations with electronic probes has slowly increased since 1996, and the bureau now has a network of about 700, referred to as automatic weather stations (AWS). In a report released in September 2017 it acknowledged issues with the performance of just two of these: Goulburn Airport (Goulburn) and Thredbo Top Station (Thredbo). These are the same two weather stations that I reported in blog posts on the 5th and 18th July 2017 as not recording temperatures measured below minus 10 degrees, respectively.

While the Bureau strenuously denied it was setting limits, Minister Josh Frydenberg nevertheless insisted on a review of the entire AWS network.

When the report was published the Bureau’s investigations confirmed that Goulburn and Thredbo were the only sites where temperature records had been affected by the inability of some Bureau AWS to read low temperatures. What are the chances? Of the nearly 700 weather stations, I stumbled across the only two with problems! Read more about this here.

Goulburn was discovered because my friend Lance Pidgeon lives nearby and was up early on the morning of 2 July concerned his pipes were going to freeze and burst – while watching the live AWS temperature readings tick-over on that weather station, then letting me know when the record for July of minus 10.4 was reached: only to see it rounded up to minus 10.0.

Thredbo was discovered because, after making a fuss about Goulburn, I wanted to check that the Bureau had lifted the limits on readings below minus 10. So, two weeks later I decided to get up early and watch the one-second reading at one of the stations in the snow fields on the Sunday morning of 16th July thinking it might be a cold morning.

Remember Amberley

When the Australian BOM announce how much hotter last year was relative to earlier years, which they usually do at the beginning of each year, a reasonable person might assume they had just added-up and averaged recorded temperature measurements, perhaps adding an area weighting. But it’s much more complicated than that. In an article in the Weekend Australian on January 22-23 entitled, ‘BoM cools the past, warms present’ Graham Lloyd explains that the Bureau has remodelled Australia’s official temperature record for a third time in nine years.

The Bureau are not saying how much the most recent remodelling (December 2020) has warmed the overall trend. They acknowledged back in November 2018 that the second remodelling added 23% to the overall warming trend.

The Bureau claims the changes are necessary because of changes in the location of recording equipment, abrupt warming or cooling relative to other sites in the region. The article concludes with assurances from the Bureau that what they do is World’s Best Practice.

In June 2014 I gave a presentation to the Sydney Institute entitled ‘Modelling Australian and Global Temperatures: What’s Wrong? Bourke and Amberley as Case Studies’. I choose Amberley because this is a military base with temperatures recorded by military personnel. Temperatures have always been recorded at this same location since 1941. My analysis was of the ACORN-SAT version 1 dataset for this location, and for the period to 2013.

At Amberley the historic minimum temperatures showed cooling at a rate of about 1 degree per century from 1970. The Bureau changed this to warming after first determined there were two statistical discontinuities in the data in 1980 and 1996, and to correct for these changed all the historical temperatures back from 1996 to 1941 were changed creating a warming trend of 2.5 degrees Celsius per century. A combined absolute temperature increase of 1.5 degrees Celsius. This is a very large adjustment.

According to various peer-reviewed papers, and technical reports, homogenization is a technique that enables non-climatic factors to be eliminated from temperature series. It is often done when there is a site change (for example from a post office to an airport), or equipment change (from a Glaisher Stand to a Stevenson screen). But at Amberley neither of these criteria can be applied. The temperatures have been recorded at the same well-maintained site within the perimeter of the air force base since 1941.

My criticisms were published in Issue 26 of The Sydney Papers Online. The Bureau has a policy of not responding to my enquiries, submissions, or peer-reviewed journal articles. However, interestingly Gavin Schmidt then the new Director of NASA’s Goddard Institute for Space Studies in New York came to the Bureau’s defence – on Twitter.

Dr Schmidt was quite blunt about what had been done to the Amberley minimum temperature series, ‘@jennmarohasy There is an inhomogenity detected (~1980) and based on continuity w/nearby stations it is corrected. #notrocketscience’.

When I sought clarification regarding what was meant by “nearby” stations I was provided with a link to a list of 310 localities used by climate scientists at Berkeley when homogenizing the Amberley data. The inclusion of Berkeley scientists was perhaps to make the point that all the key institutions working on temperature series (the Australian Bureau, NASA, and also scientists at Berkeley) appreciated the need to adjust up the temperatures at Amberley.

But these 310 ‘nearby’ stations stretch to a radius of 974 kilometres and include Frederick Reef in the Coral Sea, Quilpie post office and even Bourke post office!

Considering the unhomogenized data for the six nearest stations that are part of the Bureau’s ACORN-SAT network (old Brisbane aero, Cape Moreton Lighthouse, Gayndah post office, Bundaberg post office, Miles post office and Yamba pilot station) the Bureau’s jump-up for Amberley creates an increase for the official temperature trend of 0.75 degree C per century. Temperatures at old Brisbane aero, the closest station that is also part of the ACORN-SAT network, also shows a long-term cooling trend. Indeed, perhaps the cooling at Amberley is real. Why not consider this, particularly in the absence of real physical evidence to the contrary?

In the Twitter conversation with Dr Schmidt we suggested it was nonsense to use temperature data from radically different climatic zones to homogenize Amberley, and repeated our original question asking why it was necessary to change the original temperature record in the first place. Dr Schmidt replied, ‘@jennmarohasy Your question is ill-posed. No-one changed the trend directly. Instead procedures correct for a detected jump around ~1980.’

If Twitter was around at the time George Orwell was writing the dystopian fiction 1984, I wonder whether he might have borrowed some text from Dr Schmidt’s tweets, particularly when words like, ‘procedures correct’ refer to mathematical algorithms reaching out to ‘nearby’ locations that are across the Coral Sea and beyond the Great Dividing Range to change what was a mild cooling trend, into dramatic warming, for an otherwise politically incorrect temperature series.

Remember Bourke

The BOM deleted what was long regarded as the hottest day ever recorded in Australia – Bourke’s 125°F (51.7°C) on the 3rd January 1909. This record (recorded at an official Bureau weather station and using a mercury thermometer in a Stevenson screen) was deleted, falsely claiming that this was likely some sort of ‘observational error’, as no other official weather stations recorded high temperatures on that day.

Through access to the archived book for the weather station at Brewarrina, which is the nearest official weather station to Bourke, it can now be confirmed that a temperature of 50.6°C (123°F) was recorded at Brewarrina for Sunday 3rd January 1909. This totally contradicts claims from the BOM that only Bourke recorded an extraordinarily hot temperature on that day. There are photographs of the original records here and here. Deleting historical hot days supports the evidence for “global warming”.

The raw data for Bourke show a cooling trend (1880-1996). The weather station was moved in 1996. But the official record now starts at 1910 (omitting earlier elevated temperatures). And the Bureau adjusts down the earlier temperatures for Bourke in the creation of the official record. They cool the past artificially through the application of algorithms.

Parallel temperature records

The BOM operated traditional mercury thermometer and the newer resistance probes in parallel at about 38 sites for about 20 years. But no analysis of these has ever been published, and requests for a copy of these data are refused.

Marohasy has been very critical of the Bureau for not making these data public, so we can see the extent to which the measurements match. The A8 reports (with both measurements) were the focus of a Freedom of Information request by John Abbot, in which the Bureau initially claimed the reports did not exist, to eventually releasing 1,094 with Brisbane Airport data, representing just three years of the 15 years of data that the Bureau holds for this site. And that was only after Abbot took the Bureau to the Administrative Appeals Tribunal.

Why are they behaving in this manner? Because they don’t want analysis of the parallel data because it will show that there is a real discrepancy between the traditional way of recording and the recordings from the platinum resistant probes in automatic weather stations. I think they are having a problem getting the probes equivalent to the old mercury recordings.

If you go back to the Climategate files, remember those leaked emails, you’ve got people like David Jones from the Bureau in discussions with people at the Hadley Center in the UK and NOAA talking about how we adjust temperatures, how we don’t let deniers have access to parallel data and so it goes on. It’s very clear from the Climategate emails that people in very senior management positions at the Bureau are more interested in the data supporting the theory of catastrophic anthropogenic global warming than they are about being honest to the evidence.

The 2021 Annual Climate Statement

It is assumed that temperatures measured at official recording stations with mercury thermometers – by their very nature of being in the past – cannot be changed.  But in climate science numbers are continually changed. It is the remodelling of maximum and minimum temperature series before they are combined to calculate the mean, and then added all together, to generate an overall annual average temperature for Australia, that most affects the amount of warming announced at the beginning of each year by the Australian BOM.

The remodelling, also known as homogenization, has a very subjective component. Past temperatures are cooled, with more cooling the further back in time.  But the issue of homogenisation is not the only problem with the artificial construct that is Australia’s historic temperature record. There is also the issue of choice of weather stations and how the individual temperature series are combined to create the single series.

A new official historical temperature reconstruction for Australia is created at the beginning of each year from The Australian Climate Observations Reference Network – Surface Air Temperature (ACORN-SAT) database.

At the beginning of each year there is usually also a media release that explains how much this vast continent has warmed – even if the last year was unusually cool because of La Nina conditions. The impression is always that temperatures are increasing, and in a linear fashion. There is never any mention of the Federation Drought (1895 to 1903) because the ACORN-SAT database only begin in 1910. Hot years before 1970 are cooled down, so that the annual averages when presented as a time series no longer show cooling to 1960. Rather the numbers show continuous warming from 1910 – consistent with catastrophic global warming theory. Let me now show how this is done and with reference to the 2021 Annual Climate Statement.

Coonabarabran in New South Wales is one of the few remaining long temperature series where maximum temperatures are still recorded with a mercury thermometer. Marohasy claims that the true amount of warming across the land mass of Australia from 1910 to 2021 is close to 0.7 °C, which is similar to the amount of warming at Coonabarabran.

Weather prediction

The most accurate weather prediction systems rely on statistical models using artificial intelligence software to elucidate patterns in historical data. So, the integrity of Australia’s temperature and rainfall record is paramount.

Yet both temperature and rainfall records are being constantly eroded by the Australian BOM. Important weather stations are being closed, and the available temperature data remodelled stripping away evidence of past cycles of warming and cooling that correspond with periods of drought often broken with flooding rains.

It is also unfortunate that despite a growing budget, and increasing concern about extreme temperatures, that the Bureau has closed the Charlotte Pass weather station which held the record for lowest daily minimum temperature in Australia. That weather station was closed in March 2015. And Crohamhurst in Queensland with the highest 24-hour rainfall in Australia (907 mm) was closed in March 2003.

The simulation models currently used by the Bureau have no skill at seasonal rainfall forecasting. Models based on pattern analysis of historical data would be more accurate. The reliable forecasting of exceptionally wet summers likely requires the monitoring of volcanic aerosols in the stratosphere, as well as accurate historic temperature and rainfall records.

The Australian Bureau of Meteorology (BoM) could be exaggerating global warming by changing all the historical temperature measurements until the cooling to 1960 is changed to warming. Over the last twenty years remodelling of the historical temperature data by the Bureau has stripped away the cycles, so even cool years now add warming to the official trend. In denying the very nature of Australia’s climate, which is dominated by wet and dry cycles, the experts are unable to anticipate extremely wet weather because they have lost all sense of history.

Conclusion

Temperature homogenization and sensor change and data processing change and data selection and the addition of data from weather stations in warmer locations for more recent years have all been used to enhanced the apparent “climate change” in Australia’s temperatures. It seems as though the Australian BOM uses fraudulent means to enhance the climate change narrative in Australia. This implies that climate change is so small and gradual that it needs to be enhanced by data manipulation.

References

Marohasy J, 2022, Australia’s broken temperature record (Part 1).
Marohasy J, 2022, Australia’s broken temperature record (Part 2).
Marohasy J, 2022, Australia’s broken temperature record (Part 3).
Marohasy J, 2022, Australia’s broken temperature record (Part 4).

Acknowledgement

This blogpost comes from Jennifer Marohasy. She has a PhD in biology from the University of Queensland and is a senior fellow at the Institute of Public Affairs (a non-profit think tank, dedicated to preserving and strengthening the foundations of economic and political freedom).

Posted, April 2024

Also see: There is no climate crisis in Australia