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 He uses a multi-pronged approach looking at temperatures, historical documents, statistical step changes, and in a novel process studies the way temperature varies with rainfall as well.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 [...]
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 [...]
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 [...]
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 [...]
Let’s play the Heatwaves PR game. If CO2 had an effect we’d see a significant increase in the rate of global warming over the decades since WWII, the models would work, and climate scientists would be able to predict our climate. Since none of that is true, those with a political agenda have to clutch at noisy but marketable extremes instead. Apparently even a half-true, noisy, non-causal link is good enough for post-modern scientists.
Heatwaves are perfect for generating scientific sounding fear, but not so useful for generating actual scientific knowledge. There are an infinity of ways to measure them. They can last 3 days – 160 days, and be cut off at any number from 35 – 40C, or at some percentile outlier. They can be measured one town at a time, or on a regional or state-wide level. The permutations are rich with headline scoring possibilities. And in the end, on a long warming trend that started 300 years ago, it is obvious, inevitable, and predictable that we should score more now. What’s surprising is how often we don’t.
On ABC radio before Easter, Dr Vertessy, Director and CEO of the Bureau of Meteorology, claimed that we are seeing [...]
More errors in ACORN – The Bureau of Met wonder-database corrects for mysterious “statisticals” but not for 15 story buildings built next to the thermometers. They correct a step change that doesn’t occur in minima, but don’t correct for one that does in maxima. Big site changes are marked in some datasets but not in others. And where is the correction for obvious urban heat island effects? Bear in mind, the size of the artificial steps and corrections is on a par with the warming supposedly due to carbon dioxide. Hmmm.
The BoM database needs to be independently and publicly replicated, all the way from their raw data to the final output down to several decimal places. Then we will all know what is going on. Let’s shine a light in. If it ain’t replicated, it ain’t science.
Melbourne has one of the longest temperature records in the Southern Hemisphere. Looking at the original records it appears Melbourne maximums have not changed much from 1855 – 1995. Then they suddenly jumped or stepped up.
Tom Quirk did some sleuthing, and figured out why that happened. But what he can’t figure out is why the Bureau missed this adjustment, yet makes [...]
UPDATE: *Chris has been over the entire dataset again, and makes a correction that adjustments account for 30-40% of the rise. A bit less than half. Headline updated. See his site for the newer stats. March 9, 2015
Adjustments that cool historic temperatures have almost doubled Australia’s rate of warming.
CSIR published “Meteorological Data” 1855 – 1931
There was a time back in 1933 when the CSIRO was called CSIR and meteorologists figured that with 74 years of weather data on Australia, they really ought to publish a serious document collating all the monthly averages at hundreds of weather stations around Australia. Little did they know that years later, despite their best efforts, much of the same data would be forgotten and unused or would be adjusted, decades after the fact, and sometimes by as much as one or two degrees. Twenty years later The Commonwealth Bureau of Census and Statistics would publish an Official Year Book of Australia which included the mean temperature readings from 1911 to 1940 at 44 locations.
Chris Gillham has spent months poring over both these historic datasets, as well as the BoM’s Climate Data Online (CDO) which has the recent temperatures at these [...]
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