Today has been electrically charged, first my interview with Andrew Bolt and Steve Price on their radio show in Melbourne, then rush to the airport, trying to do a radio interview on a cellphone while checking in, make a quick post on the skeptic blacklist, off to Hobart, then discovering your luggage never made the plane.
All was not lost though (well it might be if I don’t get my luggage). The first stop my trusty guide Alan made was to the Hobart Weather Station next to the Anglesea Army Barracks at Battery Point. He said, “you have to see this”.
Looks pretty nice doesn’t it? It is very picturesque looking out over the bay and the Wrest Hotel/Casino (the tall building).
This station was showcased by the ABC radio network om 30 May 2008, here and ABC supplied this photo with the story:
Notice anything interesting? I did, but nary a mention from the ABC. They write:
“The Battery Point site being the official site is where temperatures are verified against” said Malcolm.
Malcolm went on to explain that one of the limitations with the Battery Point site is that due to its location it will be affected by the sea breeze thus the temperature may not climb as high as places further inland such as Glenorchy or Brighton.
The major change in the operation of the site over the years is that where once a person would be on hand to measure the temperature, these days everything is done electronically.
In regards to the future of the site Malcolm said it is important from the Bureaus perspective that conditions remain as constant as possible as any major changes to buildings or even trees surrounding the site can influence the temperature readings.
Whilst such changes may only alter the readings by a tenth of one degree it is just such evidence that the Bureau need to establish long term trends in climate change.
They didn’t mention the most important feature – air conditioners. Lots of them. Here’s more of my photos:
Here’s a reverse angle, a composite of two photographs to take in the wide angle:
Here, David Archibald poses next to the Stevenson Screen and the A/C heat exchanger units:
The industrial sized unit in the foreground was working so hard it had iced up its coils. David scraped about an inch of frost off of it.
Here’s the aerial view.
Note that just measuring the distance to asphalt and the nearest building, the station is less than 10 meters away, making it a CRN4 station, which would be considered unacceptable by NOAA standards. It would fail by either the old 100 foot (30 meter) rule, or the new Climate Reference Network siting rule.I don’t know how much of the building built up around it or when, but it clearly fails.
Here’s the temperature data, via NASA GISTEMP:
The jump around 1970 may be of interest related to siting, but without more time to research that metadata I can’t speculate if it is related or not. Note the plunge though the last two years. Quite a drop.
And here is what the data looks like after GISS finishes with their “homogenization” adjustment:
While I don’t have time right now to do a full analysis as I’m due for a metting shortly, I can say it appears that GISS flattened out the could snap in the 1940-1960 period, making the long term slope more positive. I’ll look at that later.
The point here is, it seems no matter where I go in the world, I seem to find siting issues with official weather stations used for climate monitoring. Stations that are long period records of historical importance suffer the most from such siting issues, because their record is valuable. Worse, when the data is adjusted, it seems to add to the warming.
Chris1958 says:
June 23, 2010 at 12:07 am
On the other hand, seeing’s it’s midwinter in Tassie, the air conditioners will all be blowing very cold air right now (but lots of hot air in summer).
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You are confusing a heat exchanger with an A/C unit. A/C cools only. A heat exchanger, like I have on my house cools in the summer and warms in the winter. It would screw up the records all year round except for the spring and fall – maybe.
It is hard to tell from a picture whether it is an A/C unit or a heat exchanger.
Since Anthony is American I am using the American definitions. Are the definitions different in Canada, England, NZ and Oz?
Please note the difference in grass color in the aerial view which is dated March 19, hot weather. The brown grass would probably be that way from exposure to the sun all day long while the green area seems to be protected later in the day by shadows from the building. Or perhaps moisture from the a/c units is spread via air outflow. Whatever the case, it can hardly lead to confidence in the temperatures recorded.
When you do the analysis could you use the same scale and range for all your charts? I noticed that the scales and ranges on these temperature data charts are different. The first chart covers 2 degrees and the second covers 3.5 degrees.
Also, could you extend the analysis to the present? These two charts seem to stop in the early 1990’s.
Gail Combs, don’t know about Canada and NZ but as a Brit in Australia I can cover two out of four. Aussies in Victoria where I live, and I’d guess the southern parts of SA, NSW, WA and probably all of Tasmania, seem to like ‘split systems’ that blow warm air in the cold months and cold air in the summer. In the UK a lot of workplaces now have aircon and sometimes warm air ducted heating, but in homes anything other than hot water radiators is unusual and a/c is rarer still. This is possibly because talking and complaining about the weather is genetic and we don’t like to have to many appliances that take the opportunity away. 🙂
Gail Combs says:
June 23, 2010 at 4:16 am
Since Anthony is American I am using the American definitions. Are the definitions different in Canada, England, NZ and Oz?
Gail, what you apparently call a heat exchanger would be called a reverse cycle air conditioner here in Oz.
Philip Bratby asks about Hobart data after 1993, graphs above.
Take a look at http://www.bom.gov.au/clim_data/cdio/metadata/pdf/siteinfo/IDCJMD0040.094029.SiteInfo.pdf
The station went to one-minute data holdings in Nov 1994, which I interpret to mean that was the end of the Hg in glass thermometry as the primary source. However, I cannot be sure. There might have been an instrumental jump, so it might be a “hide the decline” type concept.
The station opened on 1 Jan 1882, but there was a gap of about a decade of missing data from 1908 to 1918 as can be seen on the URL above. A Stevenson screen was fitted in 1895. The BoM tend to ignore temperature data before Stevenson screens or, where not yet found in the old records, round out a national date to something like 1910.
Note also in the photos that there are abundant shadows, which is another minus in Anthony’s rating scheme.
Nobody here seems to pay much attention to GISS Homogenised. Chances are, the data have already been homogenised by BOM before GISS does it again. So why bother with it? Nobody wants to ‘fess up.
Over the years, graphs have edged the decline from about 1920 to 1940 closer and closer to horizontal, not just at Hobart, but at many Australian stations. This will one day make an interesting thesis on the credibility of adjustment mechanisms and their logic.
The Stevenson screen seems to be in the shade as well.
Gail Combs / Chris1958:
I’m not an expert on heat pumps but I own a bunch of old air conditioners in rental houses. Ice on an A/C is a sign that the freon is low.
It was 57 / 39 degrees F. in Hobart on 06/22 so either way it shouldn’t be too stressed unless there is something special going on in the building. From the picture it looks like an office complex. Maybe it houses a super computer running a climate model.
Somebody should check the unit. Low freon makes a system use more electricity and that causes global warming…
Additionaly, the ground in the aerial photo looks hard and dry (probably summer time) so is lilely to be a heat source also.
You mean “heat pump(1),” though even that is an overloaded term. I’ll distinguish with (1) or (2). Technically a heat pump is something that moves heat from one place to another, usually “uphill”, i.e. from colder place to warmer place. “Downhill” you can do the same thing by opening the window, though you may not like the humidity or pond water that might come in.
Refrigerators and air conditioners are heat pumps(1) that only move heat in one direction. In HVAC systems (Heating, Cooling, Air Conditioning), heat pumps(2) are used that move heat in either direction. That there was frost on the unit says it was in heating mode, pumping heat from outside air to the inside, and releasing it back outside by air leaks and thermal conduction through the walls.
All categories of heat pump(1) have heat exchangers, though some refrigerators simply use the back of the refrigerator for that and don’t have fans blowing through plumbing and fins.
A good combination in New Hampshire is to use a heat pump(2) in fall and spring when you need heat and the outside temperature is above freezing, and then
switch to wood stove when it can be run at high output and hot.
I have a bit of experience with AC units, if they’re covered in Ice they’re not working hard, they were improperly installed/maintained! Anytime Ice forms on the coils it acts as an insulator which means that the product (what you want hot/cool) will NOT be efficiently heated/cooled. If they get a technician out there to properly service their units and adjust the amount of coolant, they’ll have lower electric bills and better cooling/heating.
As for the rest, yup typical GW hogwash, I would love to be surprised and outraged by this but I’m really not. We’ve all seen it too many times.
Obviously the unit is a heat exchanger(HE), since you would get frost on the outside coils only when you were sucking heat out of the outside air. Thus the winter temperature would be reduced at the sensor, and in the summer it would be increased when the HE becomes a A/C unit. I would bet an A/C unit was installed back in the 60s or 70s, and a heat exchanger in the 90s or later(overall energy saving device).
Clearly, without such meta data, the temperature record of this site is next to useless after the 1960s.
AC only blows warm air. If there is monthly data for this station then it is possible to identify and remove this seasonal factor in the data. In the U.S. most buildings of that age would have AC to cool the building in the summer and a seperate electric heat register or gas furnace to warm the building in the winter.
Mr. Watts,
While there has been some talk of sudden changes in the weather, climate etc – I feel drawn to say that you really do set an impossible standard for the rest of us.
You have been in the country for barely a week and already the Australian Prime Minister is facing a spill motion.
And please don’t give me any of that correlation-causation guff.
I have read enough science papers in the last few years to know that such distinctions no longer matter. 🙂
For some reason that AC was on, not heat, and the coils froze up. Something is in that building making it hot enough for the AC to be on in the winter.
Whether it’s a cooler or a heater is surely irrelevant except very close to the heat exchanger. Take a slightly larger perimeter, and you’ve definitely got a heat source, not a cold source.
Or do A/C units in the southern hemisphere somehow extract the cold from the buildings and dump it outside? (and presumably put out electric power rather than consune it while they’re at it);
Chris1958:
June 23, 2010 at 12:07 am
Keith Minto:
Perhaps there are a few plausible explanations concerning the AC / heat exchange units in winter months, but I suspect that your belief that they are kicking out cold air is wrong. Remember that it is an industrial-sized unit. In non-residential buildings, often the heat builds up even in winter due to body heat, electronics, and lighting. I have seen the air conditioning in a commercial building kick in even when the temperature outside was in the 20s (F). According to what we see in the pictures, I doubt that the temperature was that low.
Ice on an A/C is a sign that the freon is low. ( Sean Ogilvie:
June 23, 2010 at 4:53 am)
Freon! Argh… no wonder the ozone hole hangs about above Tassie…
I would surmise that increasing urbanization on the areas sloping up to the west from the station could be the primary cause of the warming trend and not the heat pump exchangers. As most know from experience at lakes in wild mountainous regions, after sunset cool air washes downhill from the forest due to plant transpiration. A 20-30 year old aerial photograph over West Hobart ought to offer some clues as to the extent of this factor.
The Melbourne Talk Show 1377 AM, Breakfast with Steve Price with Anthony is available on a podcast. As expected, it’s very interesting.
Go to: http://tinyurl.com/29yubcj
It’s 10 minutes into the program
The radio list of podcasts is at:
http://www.mtr1377.com.au/index.php?option=com_homepage&id=49&Itemid=414
Waiting for Zeke and carrot eater to show up with their magic bags…….
If this is their site where temperatures are verified against you can be thankful they are not responsible for establishing all measurement standards in the country. It would be like the grocer with his thumb on the scale for a higher price than the calibrated scale would indicate.
Wolfwalker,
“Perhaps a stupid question, but… has anyone done a careful study of the effects of these outside factors on thermometer readings inside a Stevenson screen? How much distance does it really take for the exhaust from an A/C unit to fade to ambient temperature? Are we sure that 8m isn’t enough?”
That’s a good question and I don’t pretend to have a definitive answer – but have done a bit of work on localized temperature measurements on my own (utterly unscientific just me playing around with transducers) and you would be amazed at how much of a delta t you can get by placing temperature transducers closer/further from buildings; in parking lots vs green belts, close to AC units, UHI etc. Incidentally, if you are interested and have a little spare $$ you can buy temperature data loggers from this website – it’s really a kick to do your own tests.
I’m sure there are real experts in this topic; I’m assuredly not one of them, but am technically inclined, interested, and find it fascinating and fun to run temperature tests. From my limited and unscientifically conducted tests, I would personally consider 8 meters too close for an unbiased measurement…but details of siting are also important.
Look at the case here Anthony is documenting for example – it looks to be a bank of AC units facing the Stevenson screen on one side and a road coming in at something like 45 degrees. Now picture a nice, steady, gentle breeze blowing in off the asphalt road while it picks up the heat exhaust from the AC units.
Consider that we are expecting our transducer inside the Stevenson screen to record temperature in fractions of a degree; and further we are expecting to glean from said temperature reading a longer-term trend that identities that radiative effects of man-made CO2 account for the temperature increase or some portion thereof. Quite a stretch if you ask me. And I am deaf to claims of averaging, homogenizing, re-imagining, and all the other data reduction artifices applied to surface temperature records.
Søren Rosdahl Jensen says:
June 23, 2010 at 1:46 am
Nice try, but not a good argument. Using your numbers, homogenization increases the overall trend by a whopping 59.2%. At the same time, the homogenization process decreases the uncertainty by an additional 6%.
So, to use your argument, the raw data only has a significant trend at sigma*1.69. However, the homogenized data has one at a much more significant 2.86*sigma. Apparently, when one wants to make a trend significant, just modify the data!
Additionally, this argument holds very little weight because you’re treating it like an isolated case. However, perform this same treatment to 1000 stations and suddenly the change is enormous with great significance. Additionally, if the city and nearby electrical consumption have grown in the last 100 years, shouldn’t the adjustment LOWER or even REVERSE the trend instead of adding to it?
-Scott
tom June 23, 2010 at 5:25 am
I disagree. In order to “correct” it you would need to know among other things:
The amount of electricity used on an hourly basis.
The wind on an hourly basis.
The efficiency of each of the A/Cs from installation to the present time
The history of the site in terms of construction of the buildings, fence placement, tree growth, landscaping in general and road construction.
The adjustment that needs to be made for each of these factors both individually and cumulatively.
There is another solution:
Put the thing in a suitable place and monitor it so that the site stays suitable.
Which do you think would be easier?