Blame dry weather and electronic sensors for a lot of Australia’s warming trend…
In this provocative report, retired research scientist Bill Johnston analyzes Australian weather records in a fairly sophisticated and very detailed way, and finds they are “wholly unsuitable” for calculating long term trends. He uses a multi-pronged approach looking at temperatures, historical documents, statistical step changes, and in a novel process studies the way temperature varies with rainfall as well.
His two major findings are that local rainfall (or lack of) has a major impact on temperatures in a town, and that the introduction of the electronic sensors in the mid 1990s caused an abrupt step increase in maximum temperatures across Australia. There will be a lot more to say about these findings in coming months — the questions they raise are very pointed. Reading, between the lines, if Johnston is right, a lot of the advertised record heat across Australia has more to do with equipment changes, homogenisation, and rainfall patterns than a long term trend.
Bill Johnston: On Data Quality [PDF]
“Trends are not steps; and temperature changes due to station changes, instruments and processing is not climate change”, he [...]
Wait til you see what Lance Pidgeon has found. He was looking at the BOM website temperature archive maps of Australia for early last century (using AWAP data). He was wondering how the Bureau of Meteorology could possibly create maps this detailed for specific days that long ago. He was especially curious about the remote, vast areas where there were no thermometers, yet there were wiggly jiggly temperature lines on the map, shaded as if they had meaning. I’ve heard that more people have visited the South pole, than have stood at the point in central Australia where the three large western and central states meet.
Then he noticed something positively strange — April 14th in 1915 and one year later in 1916 looked almost identical, as did the same day in 1917. The more he looked, the weirder things got. He plodded, year after year, all the way from 1911 to 1917, then through Jan, Feb, March, and so on. Worse, he tells me he could keep going right through to 1956 without seeing much change (though there are interesting exceptions). After that, temperatures of the area start to vary from year to year, like the “weather” we’d expect if we [...]
Imagine the crime of trying to audit the BOM?
Last year, Graham Lloyd wrote in The Australian about how the BOM had made whopping two degree adjustments to data which turned cooling trends to warming trends and instead of improving the data, it created discontinuities. The BOM’s eventual explanation lamely exclaimed that the stations “might” have moved. (And they might not, too. Who knows, but remember this is what 95% certainty looks like.) Lloyd wrote about how historical records of extreme heat at Bourke had effectively been thrown in the trash. Who cares about historical records?
In response to the embarrassment and revealing questions, Tony Abbott wanted an investigation. But Greg Hunt, and The Dept of Environment opposed the investigation and opposed doing “due diligence”. What are they afraid of? Instead, Hunt helped the BOM set up a one-day-wonder investigation with hand-picked statisticians that wasted another nine months before admitting that the BOM methods would never be publicly available or able to be replicated. If it can’t be replicated, it isn’t science.
The BOM’s defense is always that their mystery method is considered “best practice” by other agencies around the world — who share the same incentives to exaggerate warming, [...]
The Australian Bureau of Meteorology have been struck by the most incredible bad luck. The fickle thermometers of Australia have been ruining climate records for 150 years, and the BOM have done a masterful job of recreating our “correct” climate trends, despite the data. Bob Fernley-Jones decided to help show the world how clever the BOM are. (Call them the Bureau of Magic).
Firstly there were the Horoscope-thermometers — which need adjustments that are different for each calendar month of the year – up in December, down in January, up in February… These thermometers flip on Jan 1 each year from reading nearly 1°C too warm all of December, to being more than 1°C too cold for all of January . Then come February 1, they flip again. Somehow the BOM managed to unravel this bizarre pattern (cue X-files music) and figure out exactly what anti-horoscope-adjustments to use (and they were different in every city). Modestly the BOM did not explain to the public how clever their adjustments were; despite their $300m budget, it took volunteer Bob Fernley-Jones to reverse out the Special Horoscope Cure, and find the square wave algorithm that repaired our damaged climate records. Lucky for the [...]
There are adjustments on top of adjustments. Homogenised records are being used to correct raw records. Some man-made adjustments can infect data for miles around…
Rutherglen is a long running station in central Victoria. There are no documented site moves, but the long raw trend of slow cooling was adjusted up to a warming trend. What was cooling of 0.35C per century became a 1.7C warming trend.
Jennifer Marohasy, and others, have spent months trying to get answers from the BOM explaining why these massive adjustments were made. Excuses flowed. In the latest round, the BOM claim the changes are necessary to make the Rutherglen record match the trends in the neighboring stations. What the BOM doesn’t say is that there was no warming in the neighbours either, not until after they were homogenized. The order in which stations are homogenized matters, which rather says something important about the arbitrary nature of the adjustments. Anomalous trends from far distant and poor locations can spread through waves of homogenization until better, longer stations succumb to political correctness and show the “correct” result. Small choices about which stations to to use first in the process can make a huge difference to the [...]
There is some major messing with data going on.
What would you say if you knew that the official Perth thermometer was accurate at recording minimums for most of time in October in the eighties, but 0.7°C too warm all of December, and 1.2°C too cool in January? Bizarrely that same thermometer was back to being too warm in February! Try to imagine what situation could affect that thermometer, and require post hoc corrections of this “monthly” nature. Then imagine what could make that same pattern happen year after year. All those weather reports we listened to in Perth in 1984 were wrong (apparently). And this bizarre calendar of corrections is turning up all over Australia.
Bob Fernley-Jones has looked closely at all the adjustments done to achieve the wonderful homogenized ACORN data, as compared to the theoretically “raw” records listed in Climate Data Online (CDO) on the BOM website. He can’t know what the BOM did (since they won’t tell anyone), but he knows the outcome of their homogenization. He was shocked when he noticed a strange square-wave pattern repeating year after year; he was astonished that there were corrections calendar month by calendar month, up and down, switching [...]
Cyclones down the memory hole?
July 1935, Click to enlarge | Trove
A weak tropical cyclone has formed off the Solomon Islands, and the BOM is reporting that there has never before been a July cyclone in the Queensland region. But Warwick Hughes has already posted up details showing that there have been quite a few cyclones in July. The cyclone is hardly extraordinary, and certainly not “historic”, but what about the BOM?
Forecaster David Grant on the ABC:
“We’ve never had a July tropical cyclone in the Queensland region before.
Australia has only had one other officially declared July cyclone, which formed off Western Australia in 1996.
The official tropical cyclone season runs from November 1 to April 30.”
The July cyclone “first” scores headlines in both The Australian and The Courier Mail. “Queensland weather forecasters record first cyclone in July “. But it’s wrong. Commenter Siliggy on Warwick Hughes site found a HardenUp link listing cyclones and storms in Queensland. Some of the older July cyclones listed below may not qualify as “cyclones” under the new scale, but some clearly did — and rather than being far to the north near the [...]
The hot desert border of Western and South Australia
Lance Pidgeon has drawn my attention to the mysteriously detailed weather maps of the Australian BOM, with their mass of contradictions. The intricate squiggles of air temperature profiles suggests an awesome array of data — especially remarkable in places like “Cook”, which is a railway station with a population of four. Eucla, the megopolis in the map, has a population of 368. The shared border in the map (right) is 674km long top to bottom.
Thankfully, after 80 years of modern technology, the weather at Eucla and in the Great Victorian Desert is much more bearable than anyone would have expected. The BOM ACORN data set works better than airconditioning. In places near Eucla, where old newspapers record 43C, the BOM tells us the highest maximum that month was “under 27C”. Far to the north of there, the highest maximum stayed under 36C, but the average for that same whole month was above 36C. Go figure. It’s a new kind of maths… [or maybe the miracle of reverse cycle a/c?]
There are a half million square kilometers in this map here and almost no [...]
The BOM Technical Advisory Forum report is out. Finally there is the black and white admission that the BOM “adjusted” dataset cannot be replicated independently, has not been replicated by any other group, and even more so, that the BOM will not provide enough information for anyone who wants to try.
As we have said all along, the all new ACORN wonder-data was not created with the scientific method. Adjustments to Australian temperature data were done with a black box mystery technique that only the sacred guild at the BOM are allowed to know. Far from being published and peer reviewed, the methods are secret, and rely on — in their own words — a “supervised process” of “expert judgment” and “operator intervention”. In other words, a BOM employee makes their best guess, ruling in or out the “optimal” choices, making assumptions that are not documented anywhere.
It’s a “trust us” approach. Would we let an ASX company audit their own books? Would you buy shares in such a company, or let it inform national policy on billion dollar schemes?
Here is the entire section on replication from page 9 and 10 (below). This is what any semi-skilled PR operative [...]
Two out of three Australians live in our capital cities where the longest and best resourced temperature records would be found. These are the places where the weather reports matter to the most people on a daily basis — and where headlines about records and trends will be widely discussed. But these are also the sites which have been affected by the growth of concrete and skyscrapers, and potentially have the largest urban heat island (UHI) effect, so might need the largest adjustments.
Bob Fernley-Jones has been going through the BOM records for six of Australia’s state capitals, looking at the original raw data (at least, as is recorded in the BOM’s climate data online, called CDO). Bob compares the new “corrected” dataset called ACORN for these locations — that’s the all new marvelous adjusted data. He finds many step changes that can’t be explained by known site moves or the UHI effect. Many step changes occur in either minima or maxima, but not in both at the same time, which is also odd. As we already know, the adjustments usually cool the past — especially the minima (see all the blue lines on graphs below [...]
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