The hotter nights in Melbourne and some mysterious adjustments

Tom Quirk takes a close look at the long historic station of Melbourne. As we would expect, things have changed around the sensor since 1855 when records started.  Amazingly he finds the maximum trend in Melbourne was largely flat from 1855 – 1995. The  minimums shows a classic warming from 1945.

To find out how much of the warming in Melbourne may be due to the Urban Heat Island effect (UHI) we can compare the minima at the CBD station to one on the outskirts — and Laverton is 20 kilometers away. The site near the CBD is warming at 0.2C per decade faster than the site on the outskirts. It amounts to a whole degree warmer over 50 years, though the rate may be tailing off now. It’s hard to fit in more concrete or more skyscrapers than there already are.

Tom has a close look at the adjustments and finds plenty of questions but few answers. These adjustments are done as step changes, and Tom (and I) wonder why the gradual increase in concrete would warm Melbourne “step-wise” rather than as a slope change. Tom also wonders why the BOM say that one change is due to a “time of observation” shift. He points out that the thermometers will hold the maximum or minimum for 24 hours, so the exact moment someone goes out to read the thermometer may only affect which date the reading applies too (and really only offset it by one day), rather than raise or lower the figure. The mystery?

— Jo

The Melbourne Regional Office is located on the edge of the CBD, next to eight lanes of traffic and skyscrapers. Click for a close up.

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Taking Melbourne’s Temperature

Guest Post Tom Quirk

The Melbourne temperature record is one of the “long time” instrumental records of Australian temperature. It starts in 1855 and continues to the present day. Originally measurements were made in the Flagstaff Gardens, then when the Melbourne observatory was established in 1863 near the Botanical Gardens, the measurements were taken at that location until 1907 when there was a move to the present location on the corner of Victoria and Latrobe Streets in central Melbourne.

My great-uncle Pietro Baracchi served as the Victorian government astronomer from 1895 to 1915. He was a meticulous experimental scientist so I am following the classic rule for scientific analysis – go look at the measurements.

The raw annual average measurements are shown in Figure 1. There were no thermometer changes between 1907 and 2000 for the minimum-temperature thermometer and between 1907 and 2001 for the maximum-temperature thermometer.  As we shall see, the BOM high quality homogenized data set, ACORN-SAT, does not seem to follow the classic rule.

Figure 1: Melbourne Regional Office annual average  minimum and maximum temperatures, first measured in the Flagstaff Gardens, then at the Observatory, and then from 1907 at the present site, the corner of Victoria and Latrobe Streets.


The Bureau of Meteorology (BOM) now tells us that we can regard only the measurements after 1910 as being reliable.  We might note in passing that the raw record itself does not suggest anything wrong with the earlier data.

The maximum temperature (which generally occurs in the middle of the afternoon) shows almost no trend at all until about 1995. However the minimum temperature (which generally occurs in the early morning before sunrise) shows an upward trend starting at about 1945. With no sunlight on the ground, the night air cools but the heat emitted by buildings and human activities (the “urban heat island” effect) lessens the cooling.  The upward trend of minimum temperature since 1945 perhaps reflects the change in the number and size of the buildings in the area surrounding the location of the thermometers.

We can compare the Melbourne measurements with those starting in 1944 at Laverton, some 20 km from the Melbourne Regional Office location.  See Figures 2 and 3. The Laverton instruments were moved some 1.2 km from the original site in 1997.  One year of overlap measurements at Laverton show no significant change at that time in maximum-temperature readings, but do show a 0.2 degree decrease in the minimum-temperature readings.

Figure 2 shows an increase in the minimum temperatures (according to the raw data) at the Melbourne location compared to that at Laverton from 1944 to the present. The comparison (roughly an increase of about 2 degrees compared with an increase of about 1 degree) is almost certainly an indication of the much larger urban heat island effect in Melbourne.   Figure 3 shows both the maximum temperatures and the trends of maximum temperature in Melbourne to be much the same as in Laverton.

 

Figure 2: Annual average minimum temperatures for the ACORN-SAT homogenized Melbourne Regional Office measurements, raw minimum temperatures for the Melbourne Regional Office and Laverton.


 

Figure 3: Annual average maximum temperatures for the ACORN-SAT homogenized Melbourne Regional Office measurements, raw maximum temperatures for the Melbourne Regional Office and Laverton


The third temperature series in each of Figures 2 and 3 is of the average annual temperatures recorded in the ACORN-SAT data which has been “homogenized” by the Bureau of Meteorology. A comparison of the measured and adjusted temperature increases from 1944 to 2013 is shown in Table 1.

Table 1 Temperature increases from 1944 to 2013

Locations Minimum temperature increase 0C per decade Maximum temperature increase 0C per decade
ACORN-SAT Melbourne

0.18 ± 0.02

0.13 ± 0.03

Raw Melbourne

0.35 ± 0.02

0.21 ± 0.03

Raw Laverton

0.14 ± 0.03

0.16 ± 0.03

Raw Melbourne – Raw Laverton

0.21 ± 0.03

0.05 ± 0.05

Two conclusions can be drawn from this analysis:

  • There is a clear heat island effect in central Melbourne that is detectable in the minimum temperature measurements.  It may be as much as 0.2 degrees per decade. (Or 1 degree over 50 years!).
  • The adjustments made to obtain the homogenised ACORN-SAT Melbourne data reduce the apparent long-term temperature increases. (So these adjustments compensate somewhat for the UHI effect.)

In more detail, the ACORN-SAT Melbourne minimum temperatures before 1990 are shifted up relative to the raw data.  This seems fairly strange.  Surely one might expect that, if one is in the business of adjusting raw data, the later minimum temperatures should have been moved down to take account of the urban heat island effect. An upward correction is also applied to the maximum temperatures, but is applied only to the past and not the present. This echoes the old Polish saying from Soviet times – the future is certain, only the past is unpredictable.

Figure 4: ACORN-SAT adjustments to the raw Melbourne temperature measurements shown in Figures 2 and 3.


The Bottom line

A step adjustment does not compensate for a gradual rise from UHI.  The effect of the actual ACORN-SAT adjustments to the raw data for Melbourne is illustrated in Figure 4. There are sharp breaks rather than gradual changes that would be expected from the slow growth of the urban landscape. The breaks do no appear to coincide with instrument changes. The Bureau explains the adjustments for the maximum and minimum temperatures as being “statistical”.

Would a time of observation change need a step adjustment? As well, they say that the change in 1964 is due to the reading time of the thermometers taking place at midnight before 1964 and at 9.00 am after 1964. This seems a remarkable adjustment.  If the thermometers were read at midnight then the minimum and maximum would be for that day while a shift to a 9.00 am reading would give the minimum temperature for the day of the reading but the maximum for the previous day. How could this give rise to an adjustment? Even if the temperature was recorded for the wrong day only one day in a year would be wrong and then only by a small amount.

The explanations of the ACORN-SAT data adjustments do not provide much support for their validity.  Only one of the many adjustments seems to be specifically linked to a change in procedure, and the term “statistical” conveys no physical or procedural change as justification.

My great-uncle Pietro Baracchi would be somewhat put out by the sometimes intemperate exchanges between the “experts” over the Australian temperature record as detailed by Graeme Lloyd in The Australian over the last month. One can only guess what Pietro would have made of the manipulation of the direct measurements.

One of his duties was making weather forecasts and his attitude to this function is well put in this extract from the Australian Dictionary of Biography:

“Baracchi was best known to the general public as official weather-forecaster for the colony, a role that he did not like. To him, ‘popular meteorology’ was ‘of little practical value except as an amusement, and of doubtful credit to science’. In 1902 he supported the opinion that meteorological work carried out by astronomical observatories should be placed under Commonwealth control, and that the observatories, relieved of these duties, should remain independent State institutions. In 1906 the Meteorology Act gave control of weather services to the Commonwealth and by the end of 1907 the Melbourne Observatory was freed of its meteorological function—and never regained its former status”.

In our family he was known to have been greatly upset by his barber who told him how well he grew vegetables by reading the weather forecast in the Argus newspaper and then preparing for the opposite. It seems that the Australian coal industry is dealing with climate change forecasts with a similar approach to that of the barber some hundred years earlier.

I understand that the Melbourne measurements are not used to derive the continent-wide Australian temperatures. Even so I think that great-uncle Pietro might conclude, looking down on us now, that if the treatment of the Melbourne temperature measurements is an indication of the quality of the other homogenized measurements then the Bureau should think again about the value of this work. In the words of Pietro Baracchi this work of the Bureau may be “of doubtful credit to science.”

 

References:

Raw data: http://www.bom.gov.au/climate/data/index.shtml

ACORN-SAT information and data: http://www.bom.gov.au/climate/change/acorn-sat/

 

 

 

8.7 out of 10 based on 73 ratings

82 comments to The hotter nights in Melbourne and some mysterious adjustments

  • #
    Truthseeker

    When you look at the work done over at Ken’s Kingdom and again at Steven Goddard’s sites, you can see that this is [a major] systemic scientific [problem].

    There is no other way to describe it.


    Edits. Commenters – it easier for me if you find a better word than “fraud” to use in comments. Thanks, Jo

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    • #
      shortie of greenbank

      Edits. Commenters – it easier for me if you find a better word than “fraud” to use in comments. Thanks, Jo

      ——————————————————————————–

      Funnily enough doing a thesaurus check on the not to be mentioned word we get flimflam……. the confusion would be if we are talking a specific case of flimflam or the man himself. 😉

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    • #
      Matty

      Freud might have a field day with contortions to avoid the ‘ f ‘ word, when we all know what we really mean.

      140

  • #
    Bulldust

    It’s hard to fit in more concrete or more skyscrapers than there already are.

    I don’t know … there are some green splotches on the north(?) side of Victoria Street that could reflect more heat on the sensors if they really want to find some warming. There’s some green to the west(?) of the sensor that might also be blocking air conditioner exhaust from that building from reaching the site efficiently.

    40

  • #
    Keith L

    The BOM seems to be getting tripped up by its own porkular pie.

    110

  • #
    Yonniestone

    Here’s another photo of the Melbourne weather station on Victoria and Latrobe streets I found on WUWT, might as well place it on the runway at Tullamarine Airport LOL.

    From personal experience working outside through the night in central Melbourne it’s remarkably warmer than the outskirts and country areas, and while that sounds obvious due to the UHI effect you really have to experience it to realize just how much warmth can be stored in concrete steel and asphalt.

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  • #
    thingadonta

    One of the key arguments that the warming of the 20th century is mostly related to the greenhouse effect is that night-time or minimum temperatures are rising more than daytime or maximum ones, as expected from the greenhouse effect. But how much of this is due to concrete? Melbourne provides some food for thought.

    Note that there is a bias towards urban-based measuring stations worldwide, particularly in the early 20th century, simply because that is where people lived and took measurements.

    100

  • #
    MacHaggis

    In the 80’s, I think, the CSIRO did some work on a few stations and found that Laverton was one of 2 that showed sign of warming. What was not noted was that the warming coincided with the growth of Laverton and the wartime expansion of the airport. A heat island effect if ever there was one. I doubt that is a good comparison to use.

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    • #
      Yonniestone

      True, there’s now a subdivision either side East/West of the Williams RAAF base if you look now, also a wider Princess Hwy and a decent rail upgrade just South of it’s position.

      50

      • #
        Yeahbut

        That’s ‘Princes’ Highway and that area has exploded in the past ten years. There was nothing between RAAF base Laverton and the bay but Point Cook and weeds. It’s all houses now. Look for rising minima.

        20

  • #
    Lawrie Ayres

    Simon Birmingham is to appoint an “independent” review panel to check the BoMs record. I know that there will be a lot of interested spectators here and in similar blogs to keep everyone honest. The results will be interesting however the recommendations and follow up action will be even more interesting. Who is on the panel? If they find manipulation will heads be named? will they roll? or will it be a case of different interpretation leading to different conclusions. I have written to Senator Birmingham asking for an honest review for a change, mentioning the whitewashes in Britain and the US. I would encourage all the commenters here to let the good Senator know that there are many interested observers and that independent researchers have already noticed many discrepancies which would be expected to show up in the review.

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    • #

      Lawrie, with the BOM oversight of who is on the panel, and a mixed team, I cannot see how it will be any different to all the others.

      Yes, it is an excellent idea to write politely to Senator Birmingham and point out how often the same thing has occurred in the world of climate and been a whitewash.

      If it was an independent team it wouldn’t have the BOM in charge would it? From the information I have.. ” any nomination will be passed on the Director of the Bureau of Meteorology for consideration.”

      What we need is a really independent audit. That’s one where skeptics are resourced to replicate ACORN completely and from scratch. They get to ask hard questions and the BOM have to provide answers. If the BOM methods are world class and first rate, the critics will find nothing much to complain about. What are the BOM afraid of?

      380

    • #
      Mikky

      It will be very difficult for a team of the great and the good to get to the bottom of why homogenisation is going wrong. No doubt the algorithms themselves are OK (though there may be software bugs), but there are many adjustable parameters involved in high powered algs, and they take high powered analysts to set, and check the procedure.

      One obvious problem is the use of a fixed number (40) of stations to detect discontinuities, that high number forces the use of very distant sites in many cases, better would be to change that number according to the density, and make coastal sites special cases.

      Another problem is the false alarm rate of the detectors, and the total absence of any attempt for analysts to sieve out those false breakpoints, though that seems to be standard practice these days. In the good old days experts would probably sit for hours looking at paper plots, now the computers are just allowed to run algorithms with little quality control.

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      • #
        Geoff Sherrington

        Mikky,
        Correct.
        A basic problem exists. The screen gear is rather sensitive to change, with observed problems like state of whitewash/paint, height of grass below, more grass/less grass, etc. The effects are large in relation to the national rate of change, alleged to be about 1 degree C per century to 2010.
        The effects – and possibly more undiscovered – are largely unrecorded. Homogenisation as applied might catch some by design, some by accident, while others might even be amplified.
        These are problems with trying to correct noisy data with inadequate metadata available. Acorn was doomed by noise before birth and cannot really be improved.
        There is also a major problem caused by a subjective choice to pin the time series of temperatures to the latest readings. One effect of this appears to be to amplify trends when the trends is towards warming. Not every time, but more warming corrections arise than cooling corrections. That is, Acorn is showing a bias because of adjustment. As already documented on Kenskingdom.

        10

  • #
    Ken Stewart

    The reason past data is adjusted rather than correcting downwards current data is that you would need to calibrate the thermometers to read incorrectly compared with those in a pristine location. So nearly every thermometer in the country would be reading at different temperatures to the others. Better to have standardised and well calibrated thermometers now so we can keep an eye on them. The alternative would be to have a complicated and poorly understood correction applying every day at 101 out of the 104 Acorn sites. The adjusted (past) record tells us what the temperature MIGHT have been in the past if the surroundings were the same as now. The thermometers at Melbourne RO really are recording the actual temperature at that intersection, even though it is several degrees warmer than a few kilometers away. Also it is pretty difficult to make a gradual adjustment over the years.
    As an aside, many other sites have UHI problems but there is no way of checking.

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  • #
  • #
    Bill Irvine

    Quirk. What a wonderfully apposite name for someone who hunts anomalies.

    61

  • #

    I grew up near Laverton, and it has changed tremendously – from being open countryside when I was a kid, around 35 years ago, a place where we used to gather firewood, it is now medium density housing, a huge sea of houses on 1/5 acre blocks, with an increasing number of subdivisions appearing.

    The massive development in Laverton is being driven by the fact that it is affordable and commutable into central Melbourne. Unlike the fashionable East, where developments stretch out practically all the way around Port Phillip Bay, Altona and Laverton are only 20 minutes by train from central Melbourne.

    Altona escaped development in the past because it is the home of a major oil refinery, it was looked on as a rough working class suburb. This all changed, as the commute time to affordable housing in the East went critical – the beachfront in Altona is now lined with million dollar houses, and prices are driving development even further out, past Laverton, a solid wall of houses pretty much all the way to Werribee and beyond.

    140

  • #
    TdeF

    Is it possible explosive population growth in the second half of the twentieth century could explain global warming, with the increase in the heat island effect, whether in cities or airports and generally around people and concrete and structures, often rural landscapes which became crowded. Is it possible the perceived heating is a consequence of measurement? Do the errors exceed the effect?

    Then the failure to continue heating in the 21st century may mirror the fact that such effects are now avoided or that we have satellite measurement anyway, especially over the oceans or 2/3 of the planet.

    So if the rapid warming in the second half of the 20th century was a simple fact of where we measured, the hiatus may be a consequence of how and where we now measure. The maintenance of those high temperatures may be a consequence of a real desire not to see temperatures drop or a reflection of a belief or desire that they should not drop. Homogenization as presented is not science. Each set of data should be individually compensated for urban heat in a predictable and smooth way based on real science models, but kept. Otherwise it looks like the whole Acorn set is constructed with the presumption of the expected result.

    Who would have thought that simple errors in measurement of temperatures in Lonsdale street would cost the planet trillions of dollars, or will history show this all as another South Seas Bubble?

    91

  • #
    Wayne Job

    During the last decade or so the fudger’s doing the fudging have had to be more circumspect as many eyes are watching. Satellite temperature monitoring is also in place, thus the fudger’s have been unable to prove global warming and have achieved a hiatus because of the cooling trend. This lack of rise in the temperature record inspite of fudged data series must weigh heavily on the shoulders of the true believers of thermagedon. It is good that people who can, keep the spot light on those whose wages we pay with our taxes to behave in a way that is becoming to their position of trust.

    40

  • #
    pat

    ***”climate change” is bad!

    25 Sept: Esquire: Michael Howard: Stop Trying to Rename Global Warming
    That ship sailed years ago, and rebranding only fuels the denial fire.
    French Foreign Minister Laurent Fabius, also known as (deep breath) Foreign Minister of the Permanent Member States of the United Nations Security Council, (exhale) attended the People’s Climate March in Manhattan over the weekend. With pure intentions yet complete futility, Fabius made a rebranding comment to Reuters:
    “I don’t use the term climate change – I think the more accurate term is climate disruption.”
    It wasn’t long before every denier on social media regurgitated the same joke…
    In his 2010 presentation, White House science advisor John Holdren published the same assertion as Fabius, the same he’d been making for years: “ ‘Global warming’ is a dangerous misnomer” that undermines the severity of the threat.
    In red letters, Holdren emphasized, “We should call it ‘global climate disruption.’ ”…
    Holdren’s logic is spot on. The nomenclature “global warming” is inept and misleadingly innocent. It’s too bad this crusade for a more scientifically accurate name is boring, verbose, and around 40 years too late…
    ***It’s already asking a bit much for the average Joe to distinguish between global warming and climate change for no particular reason other than both are bad…
    So we asked two major ad firms to weigh in on this rebranding decision…
    http://www.esquire.com/blogs/news/renaming-global-warming-092314

    40

  • #
    pat

    the weekend is here, so here’s a laugh:

    25 Sept: The Week: Pascal-Emmanuel Gobry: This plan to stop global warming is so crazy it just might work
    Step one: Buy all the coal. Step two: Don’t touch it.
    (Pascal-Emmanuel Gobry is an entrepreneur and writer based in Paris, and a frequent columnist at The Week. His writing has appeared at Forbes, The Atlantic, Commentary Magazine, The Daily Beast, The Federalist, Quartz, and other outlets)
    et’s be honest: No one knows exactly what to do about global warming.
    Carbon taxes and other abatement schemes in the West might sound good, but they are of little to no importance in the grand scheme of things, given that the vast majority of new emissions will come from developing countries that aren’t going to keep hundreds of millions of people in dire poverty in exchange for a thumbs-up from Al Gore. And what of the various vaunted alternative sources of energy — wind, solar, and so forth? They all have problems, and are too expensive anyway. (What’s that you say? Don’t worry because one day they won’t be this expensive? Well, let me know when that day comes.)
    So here’s an unconventional idea, courtesy of the energy analyst Matt Frost. It’s risky. It’s very expensive. It might even be crazy…
    Frost’s plan is simple: The United States government should borrow as much money as it takes, buy up all of the country’s coal resources, and hold them in the ground in perpetuity. That way, that coal doesn’t end up in the atmosphere. It just stays up in the ground…
    Buying up all the coal instead of simply confiscating is a good idea as far as the rule of law goes. But it would also have another hugely positive effect: driving up global prices…
    As Frost notes, there are many pitfalls, and not just the lack of any specific numbers on how much all this would cost…
    Frost has been working on his plan in his spare time. It’s time for it to get a wider audience so that it can be fully fleshed out…
    http://theweek.com/article/index/268685/this-plan-to-stop-global-warming-is-so-crazy-it-just-might-work

    40

    • #
      handjive

      “This plan to stop global warming is so crazy it just might work”
      . . .
      We might as well declare war on time. Or gravity.

      90

  • #

    Jo – quite important, I think?
    I understand that an adjustment to take account of changes in the time of observation CAN sometimes be justified, and it would produce a step-change in the record. If an obs. is taken at midnight, it would record the previous night’s minimum most of the time, but the actual temperature at the time of observation when that happened to be lower. So the record of the previous day’s minimum is over-written by a lower figure. This is much less likely to occur with a 9 a.m. reading.
    This would be most important at sites where the circadial rhythm of temperature was most varied.
    Could be checked site-by-site by running the records at midnight and 9 am in parallel for a few years, to give a sensible value for a retrospective adjustment.
    I noticed in your previous posts re BOM adjustments the Time of Observation was never discussed, neither did the BOM cite it in their defence, but it is potentially the most justifiable change – if properly done, of course.

    20

  • #
    Ian George

    Re Melbourne’s Reg Office max temp data.

    It is interesting looking at the 30 year annual maximum means. From 1861-1890 the 30 year mean was 19.7C. There was little change over the subsequent periods and was still 19.7C from 1921-1950.
    It increased about 0.1C for each subsequent 30 year period reaching 20.1C during 1971-2000. Then it suddenly jumps 0.3C during the 1981-2010 period, three times greater than any other period.
    BTW
    The BoM’s ACORN adjustment site which emerged recently seems to have changed already. When I first visited it it had quite a number of station data re site changes, etc. Now it appears that only six stations have information. Does anyone have a screen save of the original info?

    60

    • #
      Ian George

      May have found the reason for the suddenly leap in the final 30 year period.
      Source http://www.bom.gov.au/climate/change/acorn-sat/documents/ACORN-SAT-Station-Catalogue-2012-WEB.pdf
      ‘An automatic weather station has been in place since August 1986 and became the primary instrument on 1 November 1996. A large apartment
      building was built across the street to the south of the site in 1996–1997, which coincides with a discernible rise in minimum temperatures’.

      So note that it says, the AWS became ‘the primary instrument since 1996’ and the building caused a ‘discernible rise in minimum temperatures’.
      But how did those changes affect maximum temps?

      In 1996, the annual mean max temp for Melbourne RO was 19.6C. From that year onward to now (17 years), the temp did not drop below 20.0C, with the coolest year being 20.4C in 2004 and the warmest being 21.8C in 2007.
      During the previous 17 years before 1996, only half the years were above 20.0C.

      20

      • #
        Ian George

        Whoops, went before I had finished.
        So the change to an AWS and the building across the road seem to have created the warming in the past 17 years for Melbourne.

        When we look at Laverton, the same seems to have happened there with a change to an AWS in 1996. Prior to 1996, there were few +20C annual max means but after 1996, +20C dominate.

        30

        • #
          old44

          The AWS has not changed, my point was that a reading from across the road in an environment similar to that which existed before the 50’s would be an interesting comparison.

          20

  • #
    old44

    The buildings on LaTrobe St are recent, coloured white and light pink and reflect the midday sun, they also block out the cooling southerly winds, added to that the massive increase in traffic in both LaTrobe St And Victoria Pde, the long delays with traffic stationary alongside the site waiting for extended periods at the traffic lights.

    An interesting comparison would be to place a weather station approx. 190 metres to the north-east inside the Exhibition Gardens, but we wouldn’t want to do that, would we?

    When the weather station was established there was clear ground from the Exhibition Building to the site and no buildings in Melbourne over 132 feet high until the 60’s and from photographic records none over 5-6 stories in the near vicinity, besides that, altering weather records would have entailed rewriting the entire record by hand.

    50

  • #
    the Griss

    Meanwhile, Arctic ice is starting to grow fast, and will quite probably reach a decadal high very soon.

    And the Antarctic sea ice is at record levels.

    All because of global warming 😉

    91

    • #
      James Bradley

      Say, Griss, has there been a report published on the findings of the Turkey Turney Expedition?

      50

      • #
        Rereke Whakaaro

        I have a copy of such a report, but it is so highly sensitive that all words, apart from articles and prepositions, have been redacted.

        I makes for “interesting” reading.

        00

  • #
    Ian MacCulloch

    Ask any emergency services helicopter pilot flying over the Melbourne CBD and the extra altitude adopted to lessen the affects of turbulence. Simple really.

    30

  • #
    Jo Fankhauser

    Here in Switzerland, the majority of the weather data collecting stations I have found are more or less new (hi-tech) and located right on the verges of arterial roads. They used to be situated in vineyards, fields, edges of forests … anywhere but immediately alongside tarred main roads

    Apparently it makes it much much easier (and less expensive?) to collect the data nowadays…. 😉

    Simultaneously, over the past few years all we’ve heard in the local media is how one maximum temperature record after the other has been broken – “news” all too keenly provided by Swiss-Meteo and the crowd of alarmists in the ETH-Zürich.

    Huge coincidence?

    I don’t want to accuse anyone of systematically altering data to suit a certain ideology, but it does seem to be conveniently “advantageous” for “proving” the media hype constantly being generated.

    Regards from Heidiland
    Jo

    40

  • #
    Mikky

    Melbourne had measurements before 1855, which is just the official start date sanctioned by BoM (probably before the CAGW thing). Here is how a heatwave in 1851 was adjusted down to a more convenient figure:

    http://www.amos.org.au/documents/item/382

    40

  • #
    Mikky

    I’ve seen that sudden jump in max temperatures in the very late 20th century at several other SE Australian records, e.g. Cape Otway, so that part of the increase is probably a genuine climate effect, maybe related to El Nino and drought?

    30

  • #
    Mikky

    I think the pretty dumb computer-based homogenisation process finds a lot of false discontinuities when it compares the target station with very distant ones, and probably any inland station in the case of Melbourne.

    All it takes is for distant sites to have a different and regionally consistent temperature trend. The target site is then seen to be deviating from a large number of comparison sites and the “dumb” algorithms point the finger at the target site. The dumb operators then do no checking and another set of dumb algorithms works out adjustments to get the innocent target record to more closely match those comparison sites.

    Actually, as an algorithm-based analyst I think there are no such things as bad algorithms, just bad analysts and bad management priorities (e.g. deadlines trumping accuracy).

    50

    • #
      Mikky

      Suppose 1/3 of RAW stations have a cooling trend and 2/3 have a warming trend. It would then be much more likely for cooling to become warming than the other way round. The homogenisation process would thus be biased to strengthen whatever is the dominant trend.

      Not sure if the above is relevant, we really need examples of the 40? stations used to detect breakpoints, but that still leaves the mystery (e.g. for Rutherglen) of how 10 adjustment stations can change RAW data to the opposite trend of the 10.

      50

  • #
    Yeahbut

    In regard to the three sites;
    The original at the Botanical Gardens would be least affected by HIE. It’s still in the gardens. The Flagstaff Gardens are smaller and surrounded by buildings and plenty of road traffic. There would have been a steady increase in temperature in the mid- late part of last century. The present site is opposite (downhill) the Exhibition Gardens. Pretty big pretty park and without Victoria St would be a better site than Flagstaff Gardens. It looks like they’re in the back yard of the local Royal Society chapter. The other side of LaTrobe St would have been the green latrine. That stretch of road (Victoria St) is one of our biggest traffic feeders on the northern side of the city. It pulls cars off the Tulla freeway and Dynon Rd into the city and out to the eastern suburbs. It’s continually busy.

    Worst site ever.

    10

  • #
    Yeahbut

    That would fit the raw data rather well.

    10

  • #
    Mat

    Urban effects on temperature are often VERY local, tens of metres. All it takes is a slightly darker/ wider road or new building to the east (retaining afternoon sun into the evening) for a step in temperatures to occur. The homogenisation process seems to have worked, it removed spurious UHI effects, as it is designed to.

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    Tim

    If temperature thermometers are so important in deciding the world’s future, why aren’t there many, many more of them – not less?

    http://blogs.telegraph.co.uk/news/jamesdelingpole/100022474/climategate-goes-american-noaa-giss-and-the-mystery-of-the-vanishing-weather-stations/

    Turkish study: “The average urban station is over 4°C warmer than rural.’

    http://www.c3headlines.com/global-warming-urban-heat-island-bias/

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      Ian George

      Same thing has happened here with the BoM using ACORN data to compile the Aust means. The number of stations has been reduced to 112 (however I believe they don’t count the capital cities).
      From the BoM’s annual summary site.
      Accessing Australia’s climate change datasets
      The Bureau is responsible for collecting, managing and safeguarding Australia’s climate archive. Several homogenised datasets have been developed from this archive to identify, monitor and attribute changes in the Australian climate.
      This statement has been prepared using the homogenised Australian temperature dataset, ACORN-SAT and high-quality rainfall data.

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    Curt

    The justifications for “time of observation” adjustments, valid or not, is more subtle than presented here. It stems from the use of the old max/min thermometers that “latch in” the maximum and minimum values during the observation period. When the thermometer is read each day, the max and min bars are reset, to be pushed up and down during the upcoming day.

    The potential problem is this: let’s say you have an unusually cold morning when you read the thermometer at 9am and reset the minimum bar. The minimum bar will quickly slide down because it is still near the coolest part of the day.

    If the next morning is not similarly cool, the minimum reading taken that morning will actually be from the previous, cooler morning.

    So observations taken near the coolest part of the day tend to have duplicate colder readings, biasing the average temperature level downward. Observations taken near the warmest part of the day tend to have duplicate warmer readings, biasing the average temperature level upward.

    That’s the theory, at least. One of the key issues is whether it really happened at most stations. It should be immediately obvious to anyone logging these temperatures that such readings could come from the wrong day. Many observers taking these morning readings would also reset the minimum bar in the afternoon so they could be sure of getting the next morning’s low reading. What percentage? Unknown, and probably unknowable. There’s the rub…

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      The Backslider

      Ahhh.. so this is why the BOM has min temperatures higher than max temperatures?

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      shortie of greenbank

      The potential problem is this: let’s say you have an unusually cold morning when you read the thermometer at 9am and reset the minimum bar. The minimum bar will quickly slide down because it is still near the coolest part of the day.

      If the next morning is not similarly cool, the minimum reading taken that morning will actually be from the previous, cooler morning.

      Perhaps they reset the minimum when reading the maximum temperate and vice-versa. This would ensure ‘double checking of the previous high or low at a time when it should not be anywhere near those maximums?

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    Roy Hogue

    The Bureau explains the adjustments for the maximum and minimum temperatures as being “statistical”.

    There’s you red flag about the readings in and around Melbourne I would think.

    One thing has been obvious to me for a long time though. Any changes to the situation around any thermometer over time definitely causes difficulty in interpreting the meaning of temperature records.

    I wonder if in the end it’s worth all the trouble, given the failure of all the predictions of disaster.

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      Roy Hogue

      Addendum:

      When I replaced the broken fiberglass screen on my patio with new aluminum screen I found that it blocked the signal from the remote temperature sensor and my clock in the bedroom went to an error display. I had to move the sensor one supporting post closer to the house to get line of sight again. I then noticed a consistently higher temperature after dark of nearly a degree F for the same reading of the other thermometer on the patio. After a while I quit tracking it, not being interested in keeping detailed records. But the lesson is clear — a change in situation mucks up the temperature record and makes it harder to interpret any trend.

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      • #
        PhilJourdan

        Everyone calls them “tin foil” hats, but they really are aluminum foil hats. 😉

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          Roy Hogue

          I hear they work well when listening to or reading climate change claims, data, etc. They stop the aliens from being able to make you believe the nonsense you’re taking in. You ought to try it, Phil. You’ll sleep much better among other benefits. 😉

          PS: I sell them. And at a good price too. Just let me know how many you want. I also have a nice bridge for sale, also at a good price…

          Oh Oh! Here come those men with the net again. Gotta run… …

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          handjive

          Tin foil hats?
          What you need is the AFDB.

          The Aluminum Foil Deflector Beanie

          All the information @link such as:

          An Aluminum Foil Deflector Beanie (AFDB) is a type of headwear that can shield your brain from most electromagnetic psychotronic mind control carriers.

          * FOOTNOTE: The American spelling** of aluminum is used here.
          If you are searching for more information on aluminum, be aware that the British spell it “aluminium” (and pronounce it accordingly).

          ** HISTORICAL FOOTNOTE: Aluminum was originally named “alumium” by Sir Humphry Davy, who later changed it to “aluminum” (perhaps in an attempt to make it more Latinized since alumen is Latin for alum, the aluminum compound that the name is derived from).

          The British (and allied English speakers) shortly thereafter changed the name once more, this time to “aluminium” so that it would again match the pattern of most other elements (helium, sodium, etc.), while the North Americans eventually decided to keep the second, slightly more traditional name.

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            Roy Hogue

            Interesting fact:

            When aluminum was first used it became highly prized for tableware such as plates, cups and so-on. It was very expensive and only the wealthy could afford it. It was found on the tables of royalty among other places.

            These days it’s very cheap and no one wants aluminum table service. But it’s still used for pots and pans in the kitchen.

            Being the lightest (least dense) of the metals suitable for construction it’s now showing up in major parts of automobiles. And of course, it has been the material of choice for aircraft for a long time.

            From treasure to everyday utilitarian material in just a few short years — what a comeuppance.

            And I see tinfoil hats are still in vogue.

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            Roy Hogue

            And if I thought that site was serious I would probably die laughing. On the other hand, how can you tell for sure?

            AFDB, sounds like something a certain character in a popular 1950’s TV series for kids was wearing. Only his had a propeller on top. I suspect the propeller enabled him to swiftly fly away from any harmful mind control signals coming from those primitive TV Cameras with all their high voltage vacuum tubes. 😉

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            PhilJourdan

            Forget the beanie- thanks for the lesson on the origin of the name.

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    Gregorio

    I live in the country about 30 miles from two different urban monitoring stations. My local temp, though not perfect, is routinely 3-7 degrees F less.

    If there is such a thing as “global warming”, it exists in the urban areas. Perhaps as the world transitions into more urban-like conditions, we will all experience more warming. I would like to be able to replicate the actual monitoring station used by the government, here on the property, and compare the temps over an extended period of time. I believe both the highs and lows would be consistently lower, but only the actual measurements will show us what actually is happening.

    Are there any other folks out there who have tried this experiment, or using different equipment, such as low cost thermometers, have had a similar result. My location is heavily treed and houses are spaced by hundreds of yards if not more in some places. This is probably how the area existed 150 years ago, so no urbanization has occurred here.

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    Bill Thompson

    I was able to get a word in edgewise with Channel 7’s resident warm-monger, Andrew O’Keefe, in Fed Square this morning. As usual with my camerawork – everything is in focus except the subject…

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    Anne

    Hi Jo,

    Unless I have missed the post, no-one has commented that the Melbourne weather site changed in November 2013 to one near Olympic park, south of the old one and near the river. The two stations are meant to operate in tandem for 18 months to ‘identify differences’. Strangely, the new site means that readings are now done every 30 minutes, instead of the 10 minutes from Victoria Street…… typical BOM improvement…

    The photograph of Victoria Street is most unrepresentative; this junction is a major one and is always full of cars.

    http://www.bom.gov.au/weather-services/announcements/vic/melb-olympic-park2013.shtml

    Cheers

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    old44

    As well as comparing the Melbourne site with Laverton, compare it with Scoresby. Although the Maximum temperature was available from1948 nobody thought to record the Minimum temperature until 1965, maybe the bloke doing the recordings didn’t have an alarm clock.

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    old44

    P.S. i forgot to mention it is situated in a field of grass, no trees that would affect it within 85 metres and no buildings or fences within 110 metres with the exception of a small shed 55 metres away.

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    Bob in Castlemaine

    A Warwick Hughes post a while back gave some insight into the new Olympic Park site replacing the old Victoria Street, Regional Office site. It is certainly further from the centre of town, but in a south easterly direction, which places it directly in the path of the hot north westerly winds that predominate on Melbourne’s hottest of summer days.

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    TdeF

    Thanks Tom.

    The ACORN step function/sudden adjustments are truly absurd, beyond belief. At a minimum the only positive is that they demonstrate the adjusted data cannot be trusted at all to 0.5C either way. If only this was experimental error. So alarmism about +2C in 100 years seems quite unjustifiable. From an experimental point of view, step functions are quite amazing and disturbing, especially without explanation. What is peculiar is that the measurements are so steady, despite the massive shifts. Not only can they not have any basis in science, there is no obvious steady increase for the expected heat island effect. This cannot be science. Who is overseeing this nonsense? Why are there no questions from the people who publish this stuff?

    Whoever is doing this ACORN work needs to go back to redo first year Physics laboratory. They would be failed. Computers do not make people smarter. ACORN is nonsense. Stick with the raw data, warts and all. That is the comparison which is needed. Australia needs to know the raw result, before the data is stuck in someone’s blender (homogenizer)

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    Ian George

    TdeF
    This is what GISS NASA homogenisation did to Alice Spring’s temperature record.
    Raw temp
    http://data.giss.nasa.gov/cgi-bin/gistemp/show_station.cgi?id=501943260004&dt=1&ds=1

    Homogenised data
    http://data.giss.nasa.gov/cgi-bin/gistemp/show_station.cgi?id=501943260000&dt=1&ds=14

    And GISS is one of the four major world temperature data ‘go to’ sites. I’d say half the temp increase is homogenisation and a quarter due to UHI – but then, I’m only guessing.

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      TdeF

      The whole idea of a world temperature, something which does not exist, is to measure effects we are told will happen and which do not seem to be happening. Things like an urban heat effect are well known, but the idea of a single temperature to define the health of a planet, is absurd. Even so, it is not moving, which disturbs Lord Monckton’s Profiteers of Doom, so it has to be fixed. You cannot average the poles, themselves very different, the sub tropic, the tropics without a model of what it all means? Even in individual sites, the search for a ‘pure’ temperature goes on. Is there such a thing? Does it matter? Why? When we cannot answer the big questions of climate science like El Nino, La Nina and why the Arctic and Antarctic are anticyclic, how can we expect to predict anything else? Even observing the mechanisms in hindsight is like watching waves break on rocks. You see everything and understand nothing.

      No, the science of meteorology is being utterly discredited by all this. The millions of hours of people measuring things with precision are being homogonenized away, sacrificed to support the concept of Global Warming, which is at best an each way bet, even without an explanation. It is impossible to even give a weather report for today’s big cities which actually covers all the city, even if we knew precisely what would happen, where and when.

      The worst aspect is that our advances in Science are being portrayed as subject to opinion and whim. Peer review is pushed as the ultimate proof, when history shows that real advances occur when peers are generally not in agreement. We even have farces where well meaning journalists like Mark Steyn are in court with lifelong data fudgers like Michael Mann.

      I cannot wait until this bubble is burst, when all this nonsense is over and I still want to see what the result would be for world temperature if the Australian results were not ‘homogenized’, something you do with an egg sauce apparently.

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    Farmer Gez

    Any chance that some of the rise is due to air conditioning units that have boomed in the last twenty five years. Heat removed from the internal house space is transferred to the outside by the unit. Is there a difference in the rate of minimum temperature rise between Summer and Winter? Just a thought.

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    scooter

    The rapid encroachment of surburbia around Laverton augurs well for warmists.

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    ecowan

    They’ve got us now:
    http://www.independent.co.uk/environment/climate-change/scientists-to-fasttrack-evidence-linking-global-warming-to-wild-weather-9773767.html
    ‘..They are developing a new scientific model that will shrink to as little as three days the time it takes to establish or rule out a link to climate change, in large part by using highly accurate estimates of sea surface temperatures rather than waiting for the actual readings to be published – a process that can often take months….’ ‘…But there are plenty of other cases where climate change is likely to have been involved, she said. Examples include last year’s record heatwave in Australia – the severity of which an eminent scientist concluded this week “was virtually impossible without climate change” – and the flooding in the UK at the start of the year, which Dr Otto’s department has just established was made 25 per cent more likely by global warming………’
    Those darn actual readings have been getting in the way again!

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