My good friend Patrick Lloyd, enamoured with the new Artificial Intelligence ChatGPT, sent me maximum temperatures for Tasmania as individual annual averages of all the daily values for all 155 weather stations since 1882. He had downloaded these values from the Australian Bureau of Meteorology’s website with the help of ChatGPT. He wanted to know from me if they showed global warming.
After importing the numbers into my statistical program, I drew a scatter plot with a fitted regression line, Chart 1. It suggests that maximum temperatures in Tasmania are not as high now as they were back in the early 20th century, and that there was a period of cooling to about 1950.
The regression equation indicates that overall, there has been cooling at a rate of 0.0051 degrees Celsius per year. Converting this into climate change speak we get a rate of cooling of 0.5 C per 100 years. This doesn’t sound right, does it?
The official historical reconstruction for Tasmania also shows temperatures cooling to about 1960, and then temperatures increasing such that since at least the year 2000, it has been very hot, Chart 2.
Clearly the official maximum temperature reconstruction for Tasmania is not just an amalgamation of all the maximum temperature series. Charts 1 and 2 show very different overall trends, though both show cooling to about 1960.
Is the Bureau’s historical reconstruction (Chart 2), a more accurate representation of historical temperatures for Tasmania than the annual mean of all the daily values that ChatGPT sourced for Patrick (Chart 1)?
Every temperature series has its limitations, and sometimes issues are just compounded when many temperature series, beginning at different times and from different locations and altitudes, are just combined. That is what Chart 1 represents, a simple compilation of everything available. It needs checking.
Patrick has suggested a solution might be to just combine the longest and most complete maximum temperature series, perhaps the best 10 percent of the 155 weather stations, and throw the rest out.
But there is an additional potential problem.
Since 1 November 1996, the Bureau have been transitioning from mercury thermometers to probes in automatic weather stations for the measurement of this temperature data. Probes in automatic weather stations represents a fundamentally different way of measuring temperatures than the traditional mercury thermometer where the daily maximum used to be manually read at 9am each morning and then the mercury reset.
Could it be that the automatic weather stations are recording hotter for the same weather?
Considering just Larapuna (also known as Eddystone Point, station number 092045), as an example, this weather station has a long and relatively compete temperature record. Larapuna would represent one of the ‘best 10 percent’ from Tasmania.
Chart 3 shows the annual average maximum temperatures (unhomogenised) as measured at Larapuna first using a mercury thermometer, and since 1997 with a probe in an automatic weather station.
Considering maximum temperatures for this location there does appear to be a jump-up of more than 1 degrees Celsius after about 1997.
How can we know if this apparent step-change circa 1997 was caused by a change in the weather, or a change in the equipment used to measure the temperatures at Larapuna?
I’ve said to Patrick, that before we begin combining the individual temperature series I would like to sort out the issue of the change from mercury to probe. In fact, this issue has been preventing me continuing with a reconstruction of Australia’s temperature history for some years now.
The probes are generally considered to be more responsive to fluctuations in temperatures and, therefore, likely to record both hotter and colder for the same weather. This is stated in the Bureau’s Research Report No. 032 The Australian Climate Observations Reference Network – Surface Air Temperature (ACORN-SAT) Version 2 (October 2018) by Blair Trewin:
In the absence of any other influences, an instrument with a faster response time will tend to record higher maximum and lower minimum temperatures than an instrument with a slower response time. This is most clearly manifested as an increase in the mean diurnal range. At most locations (particularly in arid regions), it will also result in a slight increase in mean temperatures, as short-term fluctuations of temperature are generally larger during the day than overnight.” (Page 21)
Perhaps because Tasmania is neither particularly hot, nor particularly arid, we don’t need to worry about the change over? I wonder what ChatGPT thinks? I wonder if ChatGPT can solve the equipment change over problem?
How much hotter and how much colder the probes record relative to an old style mercury thermometer will depend on the time constant intrinsic to that instrument and also on how it has been calibrated. Probes in automatic weather stations can be calibrated so the shift is uniformly in one direction.
If only we had parallel data for Larapuna, that is measurements taken from mercury thermometers and also probes in the same Stevenson screen, we could know the extent of the equivalence between the temperatures as measured with the different types of equipment. So far, the Bureau has been keeping the parallel data under wraps; the Bureau has a policy of not making the parallel data publicly available.
What are some of the other possible issues we might encounter as we combine the temperature series in search of the most accurate historical temperature reconstruction for Tasmania?
ChatGPT, via Patrick, just gave me a scatterplot for Larapuna, through until yesterday.
This is the first of a new series of blog post about reconstructing Tasmania’s temperature history with the help of Patrick and ChatGPT.
If you would like to follow along as the three of us attempt to understand how and why the two temperatures series (Chart 1 versus 2) are so different and attempt our own historical temperature reconstruction for Tasmania then, consider subscribing at my website, specifically click the box ‘Temperature Trends’ and you will start receiving information on this topic.
The photograph is of Patrick and me in front of the weather station in Tewantin, Queensland.
Suggestions for investigation.
Look at the record of daily lows, and of daily mean temperatures for the period(s) and station(s) in question. If the trend lines for those plots are consistent with those of the daily highs, at least you know that if there is a problem, it is only in the difference in instrumentation and recording practice.Obtain and review engineering test data for the different instruments.Find someone still using an obsolete instrument and compare their data to the nearest available modern station. Alternately, obtain the loan of an example of each sort of instrumentation, then compare records over a 30 to 90 day period. Extend the test period if there are inconsistencies.Compare the existing records to UAH satellite data for daily low, mean, and high. Montly data for AUS from 1979 is at https://www.nsstc.uah.edu/data/msu/v6.0/tlt/uahncdc_lt_6.0.txt and should at least give a ‘sanity check’ over the Tasmanian data,but using different instrumentation. Perhaps Dr. Spencer can suggest a source at UAH for more localized data.Obtain and evaluate urbanization and land use records for a sample of the station/locations.
Check other near by station records with the same sensor change. As well as other stations farther away. If the same post 1997 trend is evident, it is likely an artifact created by the sensor change. If others don’t show the increase it is likely a faulty sensor at this station.
Isn’t part of the problem with the electronic probes the way that BOM use the data?
From Jo Nova and Jen Marohasy over a long time there has been discussion that the WMO standard for electronic thermometers is to take 5 minute averages (to equate to slower responding mercury thermometers) whereas BOM use the instantaneous measurement. So BOM don’t comply with WMO temperature recording rules. That way a sudeen warm breeze or a break in cloud cover can create a sudden new T-max ….. and ‘global warming’.
There has also been the issue that BOM set some probes – in the coldest parts of the country – to Not record temperatures below -10C when historic records had recorded several degrees C colder. Jen Marohasy has picked up on that point and BOM finally admitted to it – again that creates ‘global warming’..
“…the Bureau has a policy of not making the parallel data publicly available.”
Why am I not suppose to think, “What are they trying to hide?”
“… the Bureau has a policy of not making the parallel data publicly available“.
FOIA request needed (Freedom of Information Act).
No FOIA request needed. The claim is flat wrong. The BoM do post this data, as a station called Edystone Point Comparison. See my comment below for details.
Nick. You are in error.
There is no parallel data available for Larapuna/Eddstone Point. That is there is no data from a mercury and probe in the same shelter at the same location.
It appears they moved the probe to a Stevenson screen about 70 metres away in October 1996, 70 metres from the original location. I’m guessing they left the mercury thermometers in the original screen and gave that screen a new number and name (comparison site).
The Bureau are only providing the data from the mercury in the screen without the probe (‘comparison’ site). More information and links in my reply below.
You keep making up new hoops for them to jump through, after the fact. The fact is that they did a comparison of mercury with AWS and posted it. That you think they should have done it differently has no bearing on whether they posted the data they have.
“That is there is no data from a mercury and probe in the same shelter at the same location.”
In fact, I think they did exactly the right thing. They wanted to see what difference there was between the old series, with an LiG in its enclosure, and the new AWS, some distance away and in a different enclosure. I think that is the difference most people what to know about. Putting the LiG in a new enclosure would not give that comparison.
In that case where is the data so that anyone can decide what the differences are? Jennifer says there is no comparison data, are you saying there is?
I am a cynic as far as this is concerned, if they have the data and won’t show it then they have something to hide and they don’t want us to know about.
“Jennifer says there is no comparison data, are you saying there is?”
Of course I am, and I gave the link. They did what they usually do in these circumstances. They created a new site called Eddystone Point Comparison, and posted the parallel data. The daily data is there too.
Jennifer is so invested in BoM bashing that she can’t simply acknowledge the fact, but immediately starts listing ways in which she thinks they should have done it.
Ad hom. That’s nasty. Just show us the parallel data. Your link shows no comparison data, it simply shows a station named “Eddystone Point Comparison”.
It is right there on the page:
But most of us would like the mercury thermometer and the new platinum resistance thermometer in the same box at the old location for art least a few years. This would actually give the answer desired. If they feel like the station should be move, then put another PRT in the new location and begin logging data at the new location as well. It’s not a comparison when you change two variables at the same time.
“It’s not a comparison when you change two variables at the same time.”
It’s exactly the comparison you want. Before and after. They aren’t trying to attribute cause. They just want to know how much difference it made changing from LiG in enclosure A to probe in enclosure B. Because that is what happened.
Since we know that you value precise use of language, please note that “data” is plural, therefore it should be “these data”.
I can nit-pick too.
To my knowledge (English was my third language) the plural of ‘the’ is ‘the’. The singular of ‘these’ is ‘this’.
Thus Nick’s ‘the data’ is correct grammar.
I think he’s referring to an earlier usage “this data”. The Journal Cell quotes the OED as saying:
“In Latin, data is the plural of datum and, historically and in specialized scientific fields, it is also treated as a plural in English, taking a plural verb, as in the data were collected and classified. In modern non-scientific use, however, it is generally not treated as a plural. Instead, it is treated as a mass noun, similar to a word like information, which takes a singular verb. Sentences such as data was collected over a number of years are now widely accepted in standard English.”
“Probes in automatic weather stations represents a fundamentally different way of measuring temperatures than the traditional mercury thermometer where the daily maximum used to be manually read at 9am each morning and then the mercury reset.”
The above quote from the article seems a bit confusing. Maximum temperatures usually occur after noon, around 1-2 pm. What have I misunderstood?
They pick up the maximum/minimum from the day before and reset at 9 am.
Yesterday’s maximum and today’s minimum.
Now I understand. Thanks.
Weather stations use maximum minimum thermometers.
“This doesn’t sound right, does it?”
No, it doesn’t. That’s because it isn’t done right.
For an exercise like this it is essential to use anomalies. The reason is that you have a varying set of stations reporting in each year. If some mountain stations were included in the later years then you will get cooling. No individual places cooled, but the set of stations changes from warmer places to cooler.
The other thing you need to do is use area weighting. Otherwise, if it happened, for example, that you had a lot of stations around Hobart, then the result is overly influenced by those stations.
Thanks Nick. So you think that if we convert to anomalies all our problems will be fixed?
No, there is still the area weighting. But anomalies would help. You’re supposed to use a fixed anomaly period, although there are alternatives.
I never ask my wife what the anomaly is, before I take the dog out for a walk…..
Nick is correct.
However, data could also be zero-centred.
But even that won’t work. No sites anywhere are homogeneous and bulking-up the data simply bulks-up the effect of their inhomogeneities, which is a site-by-site problem that Jennifer has problems understanding.
The analysis of variance Table at the top of the post shows everything that is wrong with her approach. The Table shows that of the Total sum of squares, which is a measure of total variation in the data (51.3937), the regression line in the accompanying Figure explains only 6.0647 of that, which is 6.0647/51.3937 = 11.8% (same as R^2). However, the most important number is the error component of that variation: i.e., 45.3290/51.3937*100 = 88.2%. Clearly the line fails to explain 88.2% of total variation. In simple terms, it is a very poor fit.
While the probability that trend is different to zero-trend is significant (which is the test), with R^2 less than 50% (0.500) it is meaningless. She should have looked carefully at the residuals to find out where the trend did NOT fit the data.
There were 16 sites in Tasmania with data earlier than 1882, the earliest was 1835. But how likely is it that the data for HAMPSHIRE (NEENA ROAD) is any good? And Jennifer, how would you test that? Why not just apply the protocols I have outlined at http://www.bomwatch.com.au. Study the Rutherglen example, for example, or my latest report on Halls Creek (https://www.bomwatch.com.au/wp-content/uploads/2023/03/HallsCreekbackstory_FINAL-18-Mar-2023.pdf).
It is just not possible to glue all the data for Tasmania into a single averaged series without running into problems with compounded site change effects .
Dr Bill Johnston
I’m sorry Dr Bill Johnston, but the earliest temperature data ever recorded in Tasmania is, April Fools day 1882. Any sites listed before that only have rainfall data. As for the data from HAMPSHIRE (NEENA ROAD), I’m afraid that is incredibly unlikely that it is any good for temperature. You also couldn’t use any protocols that you have outlined at http://www.bomwatch.com.au as that station has only ever recorded rainfall.
If you confine yourself to BoM data then you will not find the early Tasmanian data going back well beyond 1841, which is there as monthly data thermometer data.
Here is an example of daily data from 1825.
If “ChatGPT” can read newspapers, put it to work here.
The newspapers often do document where the data comes from and also put caveats on that.
We know it was not used in a Greenwich or Glaisher stand because they were first used in Greenwich in 1841. For the same reason we know the early 1841 BoM data was not from one either. A good clue to it having been well done is that whoever did it had a barometer.
Correct Lance. Because T affects expansion of mercury, barometer data are corrected for ambient T. barometers therefore were mostly fitted with a separate dry-bulb thermometer. There is some evidence that 1500 barometer temperature was used defacto as Tmax for the day.
That is very interesting, however at this stage, I have confined myself to just reorganising all of the official CDO BOM stuff. As for ChatGPT reading a newspaper, all I have done so far is use it to write python code and sql queries. Although, you could get it write an image to text script and loop through all of those pages to pull that data out. But, next I’m going to pull apart the station metadata so that I can organise stations by equipment used.
Good plan Patrick. Newspapers can be unreliable it would be better to feed it scanned info from old state records.
To help you past some of the mis-information pedaled here, Clement Wragge provided Hobart and many other stations in Tasmania with Stevenson screens in 1896.
You are correct. I asked BoM for all stations reporting maxima and got a list of all sites recording anything (mostly rainfall as you correctly point out).
However, as pointed-out by Lance (below), there was still some early temperature data, but where from, what sort of thermometers, were they under a tree in the shade or on a shelf on an east-facing verandah, or held in a Greenwich stand and who knows?
Eyeballing the data availability graph for rainfall at HAMPSHIRE (NEENA ROAD), its pretty useless for anything.
All the best,
Yes, that is exactly why I downloaded the data myself, and for now, just want to stick with the official data. The bom lists all the stations nationally or by state, but that is all. There are just over 17 700 stations listed nationally, but only 1765 have any temperature data. You also have to be very careful with the listed start date, as it only relates to rainfall. HOBART (ELLERSLIE ROAD) is listed as starting on the 1st of June 1893, but it’s temperature record is the earliest in Tasmania on the bom website starting on the 1st of April in 1882. On the other hand, STANLEY POST OFFICE is listed as starting on the 1st of Feb in 1870, but has no temperature records until the 12th of December in 1957.
How does that work, Nick? Say you have two adjacent 5kmX5km areas, one with 10 stations and one with 20.What’s the weighting factor for the stations? Is the 10-station area weighted 2X the 20-station area?
Seems to me that if you’re working with averages, once you averaged each area’s temps, there would be no need for weighting to compare them.
If you are combining areas, you weight according to the area – in this case equal.
If you were summing the stations into a grand sum, the stations in the 10-area should get double weighting. As you’ll see, the arithmetic gives the same result.
It is just integration.
What’s the average of 20 apples and 10 oranges?
“If only we had parallel data for Larapuna, that is measurements taken from mercury thermometers and also probes in the same Stevenson screen, we could know the extent of the equivalence between the temperatures as measured with the different types of equipment. So far, the Bureau has been keeping the parallel data under wraps; the Bureau has a policy of not making the parallel data publicly available.”
You could try some natural intelligence – ie looking. The BoM does make the parallel data available. It posts a station Eddystone Point Comparison, which runs from Oct 1996 to Oct 1998. They have daily and monthly data. The monthly averages are here.
Thanks Nick, but you are in error.
There is no publicly available data from a mercury and probe in the same Stevenson screen from 1 June 1993, until at least 1 November 1996, though there should be.
According to one set of meta data for Larapuna the probe was installed on 1 June 1993 at the original site, so there should be parallel data starting on that date. http://www.bom.gov.au/clim_data/cdio/metadata/pdf/siteinfo/IDCJMD0040.092045.SiteInfo.pdf
The ‘comparison site’ you are referring to doesn’t begin until October 1996, and for the duration of its existence there are no probes recording temperature, just a mercury thermometer according to this metadata: http://www.bom.gov.au/clim_data/cdio/metadata/pdf/siteinfo/IDCJMD0040.092115.SiteInfo.pdf
Is the ‘comparison site’ actually the original site, but was given a new number?
There is another set of meta data that says:
‘An automatic weather station was installed in late 1996, with an associated site move about 70 m southeast. Parallel observations were carried out with the former site (using the station number 92115), but some observations from the new site were incorrectly recorded against the comparison number, making it impracticable to use the parallel observations to assess the impact of the move.’ http://www.bom.gov.au/climate/data/acorn-sat/stations/#/92045
Maybe they were recorded against the new site, because the new site was really the old site?
I’m sure you’ll find criticisms, but you made a big thing about the BoM not publishing parallel data, and there it is, for everyone to see. The comparison site is a mercury thermometer being compared with the AWS. The record isn’t perfect, but they posted it.
I know nothing about Australia.
But it seems like Jennifer has a valid point in terms of scientific method and logic.
You are changing one measurement system out for another. You want to know whether this introduces a step change into the measurements. Surely you do want to know that?
Surely the sensible thing to do is mount both devices in the same enclosure? Or at the very least mount them both in enclosures of the same model within a few feet of each other. Then simply track what the readings are. If you find over a few years tht the new reads consistently higher or lower than the old, you have your answer.
They seem not to have done this, from what she and you are saying. You both seem to be referring to comparisons to a different station in a different location. And when making the comparisons between the stations, it seems that many records are missing. I find this a rather incredible breach of basic scientific method.
Then publish the readings so everyone can see whether or not the new measurement system introduces a step change.
I also find the difference between the two charts she has published in the post very strange. Surely this requires some explanation?
We are being asked to assent to massive changes in lifestyle, changes to fundamental structures of the economics and social aspects of society. Whenever you push into this agenda, you come on sloppiness and assumptions which don’t hold up. The temperatures themselves, the forecast rise, the possibility of the proposed (net zero) remedies, the effectiveness of them even were they possible. There doesn’t seem to be any risk analysis, there are no pilot projects. All that happens when you ask for normal standards of evidence when contemplating such a policy is cries of ‘denier’.
Its not good enough.
Just look, as a for instance, at the material the UK Climate Change Committee publishes showing where UK power generation is going to come from over the years up to. Its moonbeams. Absolutely no account of how intermittency is going to be compensated for. Huge build out of wind, wholly imaginary, obviously not going to happen. And a lot of wild talk about dangers from warming, no justification, and no assessment of the risks of embarking on their proposed project of restructuring the grid and moving everyone to heat pumps and EVs. Nor is there even any account of how effective it will be in lowering global emissions if they manage to do it.
The first thing we have to do is insist on normal standards of intellectual rigor on climate and energy policy. At the moment it looks to this voter like a lot of ideologues waving their arms and shouting hysterically that their pet remedies are possible and effective. And refusing to discuss either outcomes or risks.
Re the UK CCC, remember the House of Commons Public Accounts Committee in it’s ‘Achieving Net Zero: Follow Up’ report (2nd March 2022) said the following –
HM Treasury witnesses were reluctant to be drawn on the future costs of achieving net zero cautioning that the Climate Change Committee’s estimates contain ‘heroic assumptions’ potentially compounding over very long periods.
Perhaps the Treasury were too polite to use ‘moonbeams’
Ah, yes. “A courageous decision, Minister”
“You want to know whether this introduces a step change into the measurements. Surely you do want to know that?
Surely the sensible thing to do is mount both devices in the same enclosure?”
No, it is not the sensible thing. You are right that they want to know if it introduces a step change into the measurements. So they should continue the LiG device as it was, site and all, and compare with the new AWS as it will continue to be, site and all.
“But it seems like Jennifer has a valid point “
I don’t see how she can have a valid point about the site comparison, when she was refusing to acknowledge that such a comparison had been published.
Yes, you must be right on this, the original should be left alone because putting a new device in will change the environment the original one works in. The right thing would be to install the new system within a very small distance of it, so you rule out as far as possible any change of the micro climate.
If I understood you and J correctly, they did not do this. You both seem to be referring to a completely different location. I don’t know where any of these places are, so maybe I misunderstood.
I think they’re essentially at the same location, just with different site numbers.
That’s where Bill’s review of locations and metadata comes into play.
They are both at the Eddystone Point lighthouse. The new probe was in its own enclosure about 70m from the old enclosure (AWS needs power). The site number for regular readings did not change; the parallel readings were listed under a new site number.
I looked at the parallel data last year and too many daily observations are missing for it to be useful!
As you are making the point it would be reasonable to assume that you have checked. But no!
Go to the bottom of the class.
My point was that, whatever the quality of the data, they posted it.
Correct Nick, they did. And looking closely at the parallel dataset it is really not reliable (a fact they admitted in ACORN-SAT metadata),
Lets be clear about several issues. The first is that the site was never a Bureau site, it was run by the Lighthouse Service, then when lights were automated, it was taken over by Tasmania Parks and Wildlife Service and incorporated into Mount William National Park.Manual observations were probably made by volunteers after that.
The second point is that the former site used a 230-litre Stevenson screen. The AWS site in the scrub changed to a 90-litre screen (apparently) on 24 July 1997 and according to metadata, on that day maximum and minimum thermometers were removed. So a T-probe was installed on 1 June 1993, which must have been at the old site, the screen size changed in July 1997 (at the new site) and the H-probe was installed there on 30 July 1998.
Meanwhile, the new AWS site began operating in “late 1996”, probably from 1 October 1996. ACORN-SAT metadata says “but some observations from the new site were incorrectly recorded against the comparison number, making it impracticable to use the parallel observations to assess the impact of the move“. Get it Jennifer, it was the move they wanted to compare.
So while the whole exercise is a balls-up, they were recording manual observations at the new site at least until thermometers were removed and the screen-size changed on 24 July 1997. Adding another layer of confusion, they adjusted for the move from 1 January 1996, even though the new site was not operating before “late 1996“.
Blair Trewin seems to be as confused as Jennifer, certainly metadata needs to be comprehensively reviewed so they both know what actually happened (rather than assuming that nothing happened).
The final point is that ACORN-SAT says “There is little documentation on the site prior to the 1990s, but it is believed that there were no significant site moves between 1908 and 1996“. However it is pretty clear from the data that move or change took place in 1957/58. Data are definitely not homogeneous.
Simply tossing a linear fit on data that is not homogeneous, and running a 5-year average, does nothing in terms of understanding the dataset.
Dr Bill Johnston
Nick can you be my respondent to the Tax Dept please?
They’re questioning the accuracy of my income & deductions numbers.
Would you tell them I should be congratulated, because at least I posted a return?
At least they were not also fining you for not posting a return (I hope).
Over ~30 years ago the famous Dr Phil Jones of Uni of Norwich found Hobart data from 1841. I just had a quick look on BoM,s CDO page but could not see it.
Hey Wazz, would really appreciate a link and/or other information about this data.
I am sure I saw this Hobart data in one of Phil Jones’ books or papers but just scanned my copies and couldn’t find it.
I had a series of email discussions with him a few years ago when he semi retired from the UEA. I was seeking data on wind directions for England back to 1200 a subject that Hubert Lamb was interested in (his protege) and which I was trying to reconstruct as they have a fundamental bearing on temperature here and I would guess in a place like Tasmania as well.
I found him very helpful and would suggest that it might be worth corresponding with him. I find Nick pretty good as well albeit I don’t always agree with him but either the information required is available as he states or it isn’t so which is it?
The Hubert Lamb archives are held at the UEA and I would guess are digitised by now. Lamb was a great one for historic data. The Met Office in Exeter also hold lots of Digitised data-it may be there that I saw the Hobart data. Again the Met office library service are very good so it is worth making contact
You probably know this but others may not.
When Hubert Lamb left the MET Office to set up the CRU at UEA the university agreed to match the sum of money he had already raised for the unit from oil company Shell.
That would be Hobart Botanic Gardens (94030), which Jennifer could probably look-up for herself.
Dr Bill, I’m afraid that is another station that only has rainfall data, you could probably look-up the metadata for yourself -> http://www.bom.gov.au/clim_data/cdio/metadata/pdf/siteinfo/IDCJMD0040.094030.SiteInfo.pdf
Correct Patrick. Ditto my reply earlier. However, you still cannot assume they did not also measure temperature.
OK Jen –
It is from the 1986 US Dept of Energy TR027 report which I have scanned online if you go to –
On my page the link is 7 lines down from the top – the link text is “US DoE TR027 report” click on that takes you to –
If you scroll almost all the way down you come to my 2 Column Table with Headers “Appendix A” and “page 19 Station history Information and Homogeneity Assessment Details”
Australia is way down in that Table so you should go down to page 61
and there it is on the right hand side “#949750” Hobart from 1841 –
Remember Jones dealt in Mean T – max + min/2 -.
If you scroll back towards the early pages of TR027 again and see on page 2 what Jones says under “Data Sources”.
That gives you an idea of the various institutes where they vacuumed data from.
To find what exists of Max & Min T from 1841 in Hobart and possibly even daily data it seems obvious to check Tassie Archives – then Commonwealth Archives.
Another avenue could be to check ancient newspapers at TROVE – I just spent a few minutes and found daily weather numbers incl T at 2pm at from “Hobarton” –
The Hobart Town Advertiser (Tas. : 1839 – 1861) Fri 29 Jan 1841 Page 2 METEOROLOGICAL OBSERVATIONS.
I have just posted Jones 1991 mean annual T data for his 2 Hobart sites – gives you an idea where complete years data exist.
Without all that kerfuffle, as I said,
That would be Hobart Botanic Gardens (94030), which Jennifer could probably look-up for herself.
Excellent “kerfuffle” Wazz. some of the best quality “kerfuffle” anyone could hope for.
Here is the yearly average “kerfuffle” from 1840. From two different papers but in the same format. Barometer, shade temperature, rainfall and wind direction.
But where was the data from. Warwick’s station 949750 does not exist in BoM’s database. It is also ‘shade’ data. Was it under the shade of a tree, within a thermometer house or on a back verandah somewhere?? For all the kerfuffle we are really none the wiser.
It would be good to see some early data and also some details of the gear. Admiralty (navy) screens were not the same as 230-litre Stevenson screens for instance.
Not part of private idaho.
That number is not Warwicks number. For those not sentenced to BoM confinement it is found here.
And look … from Simon Torok’s thesis:
“Record commenced in 1841 ….”
So someone knows something but where is the data?
Torok can’t be taken seriously. As if it was a corrugated iron shed up until 1924. Pfft.
OK it says “some time after this”
My guess is that was a parallel experiment. Here are three pictures of at least one Stevenson screen there in 1923 with a history including most observers names from 1840.
Torok’s is the only metadata compilation, I did not claim he was accurate. While the yard was messy, interesting that they also had max & min wet-bulb thermometers; the evaporimiter was called an “Australian sunken tank evaporimiter” we had one at Wagga when I first went there, and it was replaced by an “A-pan” in the 1970s. I wonder where the original pictures are?
All the best,
Stevenson screen installed 1896.
“What was done.-Baromcter and
thermometers examined and tested by
the Queensland “Kew” standards, ther
mometers removed from the old “shed”
and exposed in the “Stevenson” screen”
I know this is only anecdotal, but as a Tasmanian latchkey kid of the 70’s .. I can declare that those summers were hotter and winters were colder.
For those interested, my best go yet at an area reconstruction, and using area weighting and anomalies, was a few years ago. Link to blog post here:
And the book chapter was published with a DOI number at bottom of that blog post.
Would the daily/monthly records be recorded in the newspapers of the day?
Van Diemen’s Land Chronicle (Hobart, Tas. : 1841) – Trove (nla.gov.au)
I see that this very long record came from the John Daly site
Temperature Data for Murray-Darling Basin, Australia, Covering 1857 – 2002 (climatereason.com)
Is it still up and running?
Yes his site is still on the www near 20 years after his passing.
Much of his work stands the test of time particularly his publicity around the 1841 tidal mark near Hobart.
Long way to go kiddo, altitude, aspect, Latitude, Longitude, faulty metadata, no-screen, 230-litre screen, 90-litre screen, bad data, faulty gear, AWS, exposure (wind-run) to the west, UHI, …. good luck to the three of you with that, I’ll come back in a while …
Use lots of sunscreen and let me know when it has finished cooking (firstname.lastname@example.org).
Yes, quite so. The number, nature and scope of unwanted variables is large. The actual temperatures are possibly incapable of explanation without wider data. Parallel data should hold some keys if the metadata and quality is adequate. You have shown the value of working with rainfall on your Bomwatch blog. Geoff S
Jennifer & Patrick,
Over the decade starting in 1980, Eddystone Point had these trends (expressed as ⁰C per decade.)
Decade 1980 first line, then Decade 2000 second line.
1980 Trend Tmax 0.0075 Trend Tmin -0.0008
2000 Trend Tmax -0.0046 Trend Tmin -0.049
All of these trends over the decade were negative or very small positive. Negative is cooling.
The 1980 decade was measured with Liquid in glass thermometers. The 2000 decade used Pt resistance thermometry.
Mean and Standard Deviation.
Decade 1980 line first, then Decade 2000 second line
1980 data Tmax Mean 16.9 SD 3.35. Tmin Mean 10.65 SD 3.44
2000 data T max Mean 18.0 SD 3.64 Tmin mean 10.62 SD 3.45
Mainly, the later decade saw a big Tmax movement to being 1.1⁰C hotter and more variable.
This fits with higher counts of extreme high values observed in the latter decade of Tmax.
This is all consistent with a change attributable to the Pt thermometry that entered service between those 2 decades, said to be starting on 1st November 1996. This effect could be artificial and superimposed on two decades which otherwise saw cooling or next to no warming.
Right now, I am analysing the decade of instrument change, starting in year 1990.
I am VERY surprised that they did not parallel run for ten years, to get a decent comparison between traditional and automatic thermometers.
It is almost as if they welcomed the artificial warming.
People love thinking of things the BoM could do. Eighteen months is the customary changeover period. In this case, the site is at a lighthouse which was being automated. Staffing ended in 2001. Who would read the LiG?
Nick said [People love thinking of things the BoM could do.]
Well for a start Nick BoM could save money and staff resources by ceasing promulgating their ridiculous Outlooks that are too often wrong.
See their latest monstrosity –
BoM March23 rain Outlook many fails
“Probes in automatic weather stations represents a fundamentally different way of measuring temperatures than the traditional mercury thermometer where the daily maximum used to be manually read at 9am each morning and then the mercury reset.”
Why would the daily maximum be read at 9 AM? Isn’t the daily maximum more likely to occur in the afternoon, such as 2 PM in winter or 4-5 PM in summer?
The thermometers have movable stops which show the minimum and maximum. Reading and resetting at 9am gives the maximum for the previous day and minimum for the current day (apart from rather uncommon outliers)
From my experience, you will find that chart 1 is mostly correct. However, you can clearly see that you will get a higher correlation if you do a non-linear plot, like a bi-nominal or sinewave. 1952 is the deep end, on average. I found that the speed of warming in K/year (use at least 4 stretches of time, as per the relevant Hale-Nicholson solar cycles) when set out against time, iow the acceleration or deceleration of warming, is on a quasi sine wave with wavelength 86.5 years. This is the so-called Gleissberg cycle.
The 86,5 years is just an average, and indeed the SH might be different to the NH.
Note that the GB cycle was well known before they began with the CO2 nonsense.
Revisiting the 87-year Gleissberg solar cycle | Bread on the water
If you want to go back in time, that far, Tmax is probably your best bet, as they read (past tense) the temperature for the day and then re-set the thermometer. Provided there was someone to read every day, it is probably the most reliable reading that gives an indication of the strength of the sun.
It is true that there is a reaction of glass with mercury and depending on the quality of the glass, this did affect the daily readings. It was only in the 70’s that they started with re-calibrations but not long after that they introduced the thermo-couples.
You can eliminate most of the problem due to the error with the mercury thermometers by looking at the speed of warming. See my comment earlier up the thread.
It was so good to receive an email just now from John Christy with the satellite data for Tasmania.
He writes: “I read your piece on Tasmanian temperatures and wanted to see what the atmosphere above Tasmania has been doing. Attached are the results from our Lower Tropospheric dataset. It looks like the peaks in 1998 and 2017 are indistinguishable. The upward shift in temperature from 1996 to 1997 looks real, but not much has happened since then. The overall trend is +0.15 C/decade with the trend from 1997 to present being +0.02 C/decade. The upper air is representative of the broader circulation in the region, so may not be able to represent the surface temps well. However, since it is a bulk atmospheric measurement, it will have a better capability to capture the influence of extra greenhouse gas forcing.
Now you are looking at Tav
That is completely different to Tmax
The more clouds and the amount of clouds being formed, the lower Tmax.
With Tav you are into ????
I am certain that surface temperature datasets are unable to detect small changes that could be attributed to CO2, coalmining, electricity generation of anything else.
Attached are two plots, the one on the left is the least squares trend for Larapunda (the same data you had in your second graph above).
Larapunda trend: 0.137 degC/decade (P <0.001); i.e., highly significant. Tmax = -9.95 + 0.0137 * Yr
Obviously getting warmer due to global warming and other sources of fertiliser. Same data as JM used but scaled 1:1.
Oh, but wait ….
Check out the residuals (variation not explained by trend) in the right-hand graph.
Hardly independent, equi-varianve across the range, normally distributed, and incidently, not homogeneous either.
This highlights the problem with all these so-called trend studies. As underlying data (i.e., residuals) show signals that are not accounted-for, the ‘trend’ is invalid.
It is not intelligent to bind all the faulty data for Tasmania together and thereby argue that the trend means anything.
From 1861 a clue to what document to search for in the Tasmanian state records.
Some extensive details from it are quoted.
EG:”It may bo observed, by Tables 9 and 11,
when compared with Tables 10 and 12, that the
City Register gives a higher temperature than
the register made at the Royal Observatory ;
and the latter, from Table 2-1, when compared
with Tablo 25, gives a greater degree of hu-
midity than the former ; but this circumstance
alone will not absolutely prove what has been
currently reported, that the temperature of the
Colony is increasing; for if all the instruments
aro supposed to assimilate, the situations of the
two Observatories are very different. Ross
Bank Observatory was some distance from the
City, and situated on the banks of the Derwent ;
while tho private Observatory is in, tho centre
of tho town, with no great amount of water