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Where should we expect UHI in temperature data 1979-2009?
|Posted by Frank Lansner (frank) on 16th January, 2011|
|Latest News (hidethedecline) >>|
- In the largest urban areas or in areas with the fastest growing population?
[Note 17/1: UHI in limate data originates from changes of UHI over a period. So the general discussion is not if a city has UHI - it has - but if UHI in a town has grown due to expansion of the city or other factors. A more permanent big-city UHI will not disturbe temperature readings. So when we speak of UHI in global temperature trends, then we refer to an average UHI increase around the temperature stations world wide.]
In the article http://wattsupwiththat.com/2010/12/16/uah-and-uhi/ I suggested:
1) Ground based ocean temperature data matches fairly the UAH TLT ocean data - but the ground based land temperature has a warmer trend than UAH TLT land data. I argued that this extra heat in the ground based land data might originate from UHI, adjustments and siting problems.
2) The UAH TLT land vs ocean data has a rather similar trend as if they seek an equilibrium in temperatures. I mentioned the problem for ground based data that the land data vs. ocean data has an ever larger difference so far not explained.
Point 1) was intensely debated which as always brings about more knowledge. Especially one argument used based on expectations to where geographically UHI should be seen strong in the satellite years 1979-2010 has been rewarding to examine closer.
Bob Tisdale has made a very useful grid-wise compare of TLT UAH data vs GISS data worldwide which enables further studies on point 1).
This could shed light on the UHI question: If Ground based GISS data warms faster than UAH TLT in areas where we expect UHI, then perhaps a UHI signature is confirmed. And UAH data in compare with GISS data an indicator of UHI.
Example: Central North America/USA.
Bob finds no significant difference between USA temperatures for UAH vs. GISS ground based for 1979-2009. If one expects that there should be UHI in USA in this period, then according to my suggestion, we should have seen GISS ground based warming faster than UAH USA temperatures.
However, for example McIntyres calculation of Petersons USA city-vs-rural data shows no UHI 1979-2009 for USA either... So perhaps we should not expect UHI 1979-2009 for USA?
Based on Tisdales results I have used the following labels on the graphic below:
"NoUHI " : Means that GISS ground based data often from cities and airports has a rather simlar warming trend compared to the TLT UAH (- sometimes just a little extra warm in GISS data).
"UHI" : Means that GISS ground based temperature trend is significantly warmer than UAH TLT and thus contains something that cannot be detected by satellite, we call it UHI for now.
Heres then how we should expect UHI to be distributed world wide based on Tisdales results:
Fig2 So... We should have UHI 1979-2009 in areas with not that dense urbanization? And not in the USA and similar places? Can this be true? Well, I don’t blame anyone for saying that this is not really in favour of the UHI concept. (The North Atlantic "UHI": See "Post Scriptum B")
But before throwing data out in the drain and before skipping the UHI idea, do we actually know where geographically we should expect UHI 1979-2009? Lets examine it.
Where should we expect UHI in temperature data 1979-2009?
Lets take a look at the “bible” of UHI Thomas Karls analysis of UHI 1901-1984 done on temperature mostly without temperature corrections done in the period of the global warming debate - and the biggest research of its kind:
Thomas Karls data suggests that increase in population number for cities already large has much less UHI effect generally than a similar increase in population number for a small town. That is, UHI should be expected NOT necessarily in the biggest urban areas of the world, BUT in the areas with biggest relative population growth.
So where are the areas with the biggest relative population growth?
They are here:
Population growth rate: I found 2 such statistics from the 1979-2009 period, upper effective in 1990 and the lower in 2006.
Result: North America, Europe and Australia has the lowest growth while Africa incl Sahara, and Brazil and more countries in South America and also large parts of Asia has the biggest population growth rate.
So lets take a look at the UHI expectations from fig 2 from Bob Tisdales data compared to the relative population growth maps. I have pasted the "UHI"- and "No UHI"-expectaions from fig 2, Bob Tisdales data onto the map showing relative population growth:
- The match with the relative population growth 1990 and 2006 is perhaps better than we could have demanded since many factors hypothetically could have made the picture blurry.
Bob Tisdales data seems to confirm that the divergence in GISS ground based data compared to UAH TLT could possibly be due to UHI, at least partly. At least if we expect UHI mostly from areas not just with a large Urban fraction but rather UHI mostly from areas with the fastes relative growth. And this sounds to me reasonable.
Update 25/1 - Russia/Asia:
The national population growth rate of Russia is near zero in the period, but Bob Tisdale found extra heat in GISS data compared to UAH over Siberia. This further supports the population related UHI problem because population over Siberia did in fact rise in the period, here a russian statistic from 1995:
But since most Russians live in the Euopean part where population has been declining, the national population numbers are not useful to justify the warmer GISS data compared to UAH over Siberia. So, population numbers suggests UHI over Siberia, but not the European part of russia.
Then, my "UHI" over southern asia: The Tisdale Asia covers Siberia and southern Asia, but the extra heat in GISS compared to UAH is larger for this Asia area than just the Siverian area. Therefore, the Southern Asiea has the largest divergence GISS vs. UAH.
--> I will within a short time present a new article without any reference to Bob Tisdales results, but in stead a much more detailed analysis where also regional population data from all the wolrds largest countries will be used in addition to national population data.
UAH ocean temperatures , UAH land temperatures and the most often used SST´s has similar warming trend. The ground based land temperature trends have warmer trends.
This may indicate that the warmer ground based land temperatures has a faulty added warm trend from UHI, adjustments and siting problems.
Further more, the long term resemblance between UAH-land and UAH-ocean appears logical and correct since temperatures over land and sea respectively should have a tendency to seek equilibrium at least on longer term. This further points to Ground the based land data type as the source of errors.
Finally, this writing: It appears, that the UHI fraction in GISS ground based data is likely if we expect that UHI should be most significant in areas with high relative population growth. The rather good match between relative population growth and divergence between GISS and UAH TLT does in fact also a support to the general idea, that UHI plays an important role for the ground based temperatures often measure from cities and airports.
Finally we must add, that many other factors than UHI can play a role - see for example "post scriptum B".
However, notice in fig 1 how the divergence between GISS groundbased data and UAH data just vanishes all together when we focus on an area with no UHI as McIntyres Peterson data suggests. This could indicate that UHI plays a role not that tiny for the descrepancy between UAH land data and Ground based land data.
* Post Scriptum A *
Where NOT to measure UHI…
Finally a little example I have to mention concerning UHI:
When speaking of “where not to measure UHI”, the absolute best spot in the world is London.
Central Southern England is one of the areas of the world with highest population density which makes the area one big urban warmed area. In Southern central England, no matter from where the wind comes from it will come from a highly populated area, and thus there are no truly rural areas to test UHI with. On top of this, ever since 1900, London has been a multi million population city, which is extraordinary. So, any attempt to measure UHI using London of all towns compared to a non rural surrounding area is a remarkable quest indeed.
Non the less, London of all places is one of the corner stones when skepticalscience argues that there is no UHI worth mentioning:
* Post Scriptum B *
In Fig 2 above, I have inserted a “UHI”” mark in the north Atlantic.
This is not the Faroe Island or the like, no its due to a GISS (LOTI) ground based data for north Atlantic with warmer trend than AUH TLT, Bob Tisdale:
Obviously this is an example where UHI does not play a part in the difference between GISS and UAH. For the oceans, the GISS (LOTI) are hadcrut SST data sampled 2 meter under surface. In contrast, UAH mostly relects low Marine Air temperature, and these to different temperature sets are likely to induce some differences.
In the period in question, the AMO current has sent stil warmer waters to the North Atlantic. My guess is that an event like a strong AMO rise in the North Atlantic might play a role. The AMO is know for warming up the air of the North Atlantic land and sea areas, and if the heat comes from the waters, the AMO current, then perhaps its not impossible that water temperature in the period is slightly warmer than the air? This is what it take if the warm AMO current is warming up the Northern atlantic land areas etc. Just a guess, obviously.
* Post Scriptum C *
I have taken the liberty to write "No UHI" on the maps for Australia. In fact Bob Tisdale got GISS to have lower warming trend than UAH TLT on his "Australia".
In my maps for relative population growth, I only have full countries, but Bob Tisdale chose a fraction of central Australia, not the whole Australia. but if we use all of Australia the GISS trend is much warmer.
Heres a compare of the GISS (LOTI) temperature trend for Australia 1979-2009 [little picture] compared to recent development in population [big picture] - and we see that the actually slightly falling GISS trend for central Autralia happens to be accompanied by declining population in central Australia:
However im sure that world wide one could find many areas where the match between population and heat trends will be poorer than this due to a row of other factors.
More articles by Frank Lansner
Last changed: 25th January, 2011 at 12:33:52Back
|Hopefully My Final Reply To Frank||By Unknown on 22nd January, 2011 at 02:56:40|
|Frank, with respect to your ongoing efforts along this line research, please do you and me a favor.
Please do not refer to or link my posts, please do not refer to me by name, and please do not link to or use my graphs in your posts. If you adhere to my request, I will have no need to return to your website and find error with what you've written and presented.
|Checkout update Sunday :-)||By Frank Lansner on 21st January, 2011 at 15:48:30|
|Dear Bob, I honestly believe that when I update with Asia areas on sunday, then the message of the article is exactly the same (!)
But im very interested in getting these things as correct as possible, and I dont mind at all that you inform these kond of things. This is what I would call a help and its welcome.
But before I conclude I wanna now the outcome Sunday. has to Fly off now.
|Yet another reply to Frank||By Unknown on 21st January, 2011 at 15:18:09|
|Frank, you included the following text from the post in your recent comment, “this is an example where UHI does not play a part in the difference between GISS and UAH. For the oceans, the GISS (LOTI) are hadcrut SST data sampled 2 meter under surface. In contrast, UAH mostly reflects low Marine Air temperature, and these to different temperature sets are likely to induce some differences.”
Frank, you miss the point once again.
You have not identified the cause of the difference between the sea TLT and SST. How do you know that the same factor that is causing the difference between sea TLT and SST is not responsible for the difference between land TLT and land surface temperature? You don't. And that simple fact undermines all of your conjecture about the growth in population being responsible for the land differences.
In other words, YOU have to identify the cause of the Sea TLT and SST difference and remove that factor from the Land TLT and Land Surface Temperature data, before you can make any other claims about the land surface data.
You replied, "Then you show me a graphic that again points out the SST issue above, I have answered above.
The graphic and your text also shows, that I have misunderstood where “EurAsia” was etc.
Has this got any significant impact on the main points of the discussion?"
Of course it does. It shows that you either misrepresented what I presented in my post or you misunderstood it. Either way, it does not reflect positively on your research efforts.
|Hi Bob...||By Unknown on 21st January, 2011 at 10:01:08|
|I still don’t see my repeted basic questions answered Bob, And so your claims of where there should have been UHI etc. appears not really supported. I cant change that.
In stead you write:
“Has the population grown on the Atlantic, Frank? ”
Again, you are rhetorical. As explained generally for the oceans in the article:
“this is an example where UHI does not play a part in the difference between GISS and UAH. For the oceans, the GISS (LOTI) are hadcrut SST data sampled 2 meter under surface. In contrast, UAH mostly reflects low Marine Air temperature, and these to different temperature sets are likely to induce some differences.”
You write more… :
“The only comparison graph of SST and Sea TLT was for the coordinates of 60S-60N, 78W-80E, and it showed that scaled SST anomalies of the North Atlantic AND the South Atlantic AND the West Indian Ocean had a higher linear trend than the TLT anomalies. It wasn’t only the North Atlantic, Frank. “
Yes, Bob, the explanation is general for oceans. I showed just the onle ocean example you have promoted to me and no more since this is an article of where to expect UHI.
Then you show me a graphic that again points out the SST issue above, I have answered above.
The graphic and your text also shows, that I have misunderstood where “EurAsia” was etc.
Has this got any significant impact on the main points of the discussion? No.
The Sibirian hotspot: On the maps in the article, above I just show national population numbers, and for Siberia, as a part of Russia one could have expected some population growth not reflected in russain national population numbers.
However, I found this population development of Siberian cities showing that Siberian cities – unlike rest of Russia/Sovjet – has grown in size 20 – 50% from 1979 to 2009.
This is not as huge a population growth as for example Africa, South America, BUT, the discrepancy between GISS vs UAH TLT is not as big for the Siberian hotspot as it is for Africa and South America.
So things still add up even though many other factors than UHI is likely to have impact. So examining the Siberian hotspot if anything just confirms UHI related trends in the UAH TLT-GISS divergence.
Then the asia squarre includes not only some of these Siberian areas, but also Pakistan, India, Burma Thailand, parts of china, and its true the “UHI” should have been place more to the East than I have done, but as I said, this doesnt change the message:
The original UAH TLT – GISS land compare I did logically I suggested should reflect UHI problems in data (along with adjustment and siting problems) AND your main argument Bob, that the geographical land distribution of UHI should be seriously pointing against this is still no way near supported. (I will adjust the fig. for Asia. Like it or not, but this dialog has made many interesting things pop up. The Siberian hotspot ... population growth in Siberia... nice!!)
|And Another Reply From Bob Tisdale to Frank||By Unknown on 21st January, 2011 at 01:04:20|
|Frank: Let’s first address a few basic errors in your post. If you want me to comment then on your Brazilian analysis, I will be happy to point out the errors in it also.
Your Figure 2 calls into question every assumption you’ve made.
Has the population grown on the Atlantic, Frank? You have a “UHI” stuck in the middle of the North Atlantic in your Figure 2. You attempt to explain it in your Post Scriptum B by guessing it’s the AMO, and you admit it’s a guess. And your guess is wrong since the AMO data is SST data. The AMO data is North Atlantic SST data that has had its trend reduced. The fact that you have UHI shown on the North Atlantic destroys all other assumptions you have made in this post. You also linked another of my posts in your Post Scriptum B to confirm the reason for your placing a “UHI” label in the North Atlantic. Here’s the link:
Did you bother to read that post, Frank? The only comparison graph of SST and Sea TLT was for the coordinates of 60S-60N, 78W-80E, and it showed that scaled SST anomalies of the North Atlantic AND the South Atlantic AND the West Indian Ocean had a higher linear trend than the TLT anomalies. It wasn’t only the North Atlantic, Frank. I spent a significant time on the North Atlantic in that post to show the differences in the response there to ENSO, and to show how the responses of the North Atlantic SST anomalies to ENSO extend far longer than other ocean basins.
Another point about your Figure 2: You wrote as an introduction to it, “Heres then how we should expect UHI to be distributed world wide based on Tisdales results:”
And once again you have misrepresented my work. Look at your Figure 2 and my Figure 1. Here’s a link to my Figure 1:
There’s a significant difference in your portrayal of the Asia and “Siberian Hotspot” data. You show the Asia data in your Figure 2 with a “UHI” over Iran and Afghanistan, but the Asia data I’ve used in my post stretches all the way east to the China coast and all the way north to the Siberian coast. And that makes a significant difference when you then place the Asian “UHI” on your population maps, your Figure 6.
The coordinates for the Asia data were clearly marked on the graph (my Figure 6) as 27N-70N, 54E-105E.
And to compound your misrepresentation, you have added a “No UHI” in Siberia in your Figures 2 and 6. But both the Asian data and the “Siberian Hotspot” data (my Figure 7) show significantly higher trends for the GISS data. And that contradicts your description of your “No UHI” marking. You wrote, "'NoUHI ' : Means that GISS ground based data often from cities and airports has a rather simlar warming trend compared to the TLT UAH.”
Here’s a link to your Figure 2 that I have marked up to illustrate your errors/misrepresentations:
|Hi Bob, Brazil and 1200 km GISS smoothing||By Frank Lansner on 20th January, 2011 at 03:30:21|
|Bob you write:
“Frank. It is YOU who are claiming that there has been an increase in urban heat island effect in the Sahara desert and the Brazilian jungle. But you are not seeing the OBVIOUS. Why does GISS need to use the 1200km smoothing, Frank? Because there are no surface stations there. If there are no surface stations there, are there urban areas? If there are no urban areas, how can there be urban heat islands?”
Bob… Im gonna have to repeat again: Fact is that GISS uses 1200 km smoothing and thus reaches areas where no people lives. The stations are rather often urban.
Here are again 6 long series of Brazil, 5 urban and 1 rural:
Manaus in the middle of the “Brazilian jungle” has grown fast to a population like Hamburg of Germany, and Cuiabá to a size like Bremen.
Here are marked the 1200 km radius from just these two series, upper picture is GISS 250 km grid 1900-2009, lower is 1200 km radius smoothed:
So yes, the “Brazilian Jungle” in GISS 1200 km smoothing is covered by city UHI trends from fast growing cities. Therefore its not really a surprice that a compare with UAH (rural!) shows a difference.
Its not density of population in the jungle that matters, its the growth rate of population from the smaller or bigger cities where temperatures where measured and smoothed out 1200 km.
(In GHCN/GISS data, there has been carries out 4-5000 UHI adjustments so it can be a little tricky to evaluate UHi from these data)
Who should show what:
“If YOU had performed a reasonable analysis, Frank, you would have discovered that the vast majority of the difference between TLT and surface data exists in only one area of the globe. All areas would be impacted by UHI if it had a significant effect, but they are not. And that fact alone contradicts your claims that UHI is the primary reason for the difference between surface and TLT data. “
So, Bob, it is you who must show that your hunch or claim “All areas would be impacted by UHI if it had a significant effect” is correct.
If you don’t, there is no weight in your claims. This I think you should do before demanding anything from others.
If you had performed a reasonable analysis, Frank, you would have discovered that GISS land surface data for much of the United States has a lower trend than the TLT data:
If you had performed a reasonable analysis, Frank, you would have discovered that there is little difference between GISS land surface data and TLT data for much of Europe:
If UHI was such a dominant factor, why are they so similar, Frank?
Again, why should UHI have been a dominant factor in Europe and north America 1979-2009? Why not just in the areas of the world with fast growing population as std UHI knowlegde suggests?
This is also what you have to show or document if your arguments should have any weight.
You have to tell where this hunch/idea of yours comes from.
When using ordinary population growth rates in the article above, I dont find Europe and North America as places where the UHI should have been strong.
“There’s no reason for you to continue arguing with “Unknown” and me about this, Frank. The errors in this post are obvious.”
PS: In my first article AND in the present article i wrote that the land-descrepancy between UAH TLT and GISS could be for example UHI, adjustment errors or siting problems. This has even been repeated to you so you must be fully aware by now. So, if tere are 1200 smoothing errors also it sounds very reasonable!!! And certainly only supports that groundbased land data has errors. The 1200 I have challenged myself earlier.
The main point of all this is, that it is the ground based land data that holds errors in form of UHI, adjustment errors and siting problems. I have not changed my opinion on this since we talked about it last time.
|Why Are You Asking Anything Of Bob Tisdale, Frank?||By Unknown on 19th January, 2011 at 11:58:42|
|Frank stated in the subject, “and.. its odd you dont demand the OBVIOUS from Bob
I’m not making any claims about the data, Frank. You are. Don’t make me responsible for anything to do with this post, Frank. It is YOU who are claiming that there has been an increase in urban heat island effect in the Sahara desert and the Brazilian jungle. But you are not seeing the OBVIOUS. Why does GISS need to use the 1200km smoothing, Frank? Because there are no surface stations there. If there are no surface stations there, are there urban areas? If there are no urban areas, how can there be urban heat islands?
Frank asked, “Now, in the case of Africa, which is most likely true? That the general placing of the temperatre stations is in an areas with population growth or in places with no population growth?”
YOU are not considering population density, Frank. There are less than 2 persons per km^2 in the Sahara.
Now ask yourself, what UHI effect will there be if there is a 4% population growth in an area with less than 2 persons per km^2? None.
And as “Unknown” pointed out to you, “the sahara should not have a city trend. if the sahara has a city trend, then the difference that you're seeing is an error caused by the 1200km smoothing.”
There’s no reason for you to continue arguing with “Unknown” and me about this, Frank. The errors in this post are obvious.
|and.. its odd you dont demand the OBVIOUS from Bob||By Frank Lansner on 18th January, 2011 at 22:35:52|
"did you perform an analysis of these areas and their population growth?"
Where is your objectivity?
Take a close look at the population growths around in central and north africa as i showed you in the article:
A Goooood long look.
Now, in the case of Africa, which is most likely true? That the general placing of the temperatre stations is in an areas with population growth or in places with no population growth?
Honesty, please. Take your time.
Now, how can Bob just claim (out of the blue?) that there should NOT have been indication of UHI from Africa??
If you are so busy demanding that I should have done this and that which is all very fine, WHY ON EARTH dont you demand the obvious that Bob does HES work to begin with???
It screems to the sky, that it is Bob who needs to do some analysis and documentation before claiming things about where UHI indications should have been.
I Have done the above rough population based analysis to begin with. I have opened the "ball" of studying where to expect UHI, roughly. What did Bob do on this before making conclusions to begin with?
(Its funny how this demanding more analysis resembles Bobs debate style, are you in family?)
|“Unknown” please identify yourself next time.||By Frank Lansner on 18th January, 2011 at 22:15:14|
|This discussion originated since Bob Tisdale suggested that the UAH-GISS divergence could not reflect UHI much since he expected (for some reason I have yet not seen explained) that this UHI should then have been in USA, Canada, Europe etc and NOT in Sahara and more.
A simple check of relative population growth indicates that these expectations does not seem to be on solid ground, and Bobs argumentation are just not really supported.
So for now it’s up to Bob to document that the stronger UHI indication from UAH-GISS divergence should have been in the areas he have suggested. This should be he’s next step.
------ * ------
THEN, could we go further, and say that the population growth proves UHI?
That UAH-GISS divergence “match” with population growth proves UHI?
No, that would be to take this too far!
The data so far with squares not identical to national borders for which we have population numbers and so on is a “rough” data to work with as I said in the article.
UHI-effect is shown beyond any doubt by the work of Thomas Karl as I showed in the article:
and then for in the many results I have shown some links in these comments.
These data are a very strong evidence for a UHi problem in temperature data.
However, IF it was true that UAH-GISS divergence seriously contradicting the very strong case for UHI THEN things would have been more muddy.
But just to say apparently out of the blue (?) that UAH-GISS divergence occurs in the wrong places does NOT rock the strong UHI case in anyway. AND the rough “match” in the article above slightly supports the UHI case which was already strong.
K.R. Frank Lansner
|Reply to Unknown on 18th January, 2011 at 17:47:14||By Unknown on 18th January, 2011 at 18:47:02|
|I agree with you completely.
Additionally, you wrote, "where there are known UHI effects, known surface station siting problems, etc."
There are also differences in the way land TLT and land surface surface temperature anomalies respond to short-term variables such as ENSO and the way they respond to long-term variables such the AMO.
|reply to frank||By Unknown on 18th January, 2011 at 17:47:14|
|frank said, "2) USA has much smaller relative population graowth rate compared to Africa or Brazil (!) so the fact that Bob Tisdale actually finds the UAH TLT difference over Africa and Brazil just seems to somewhat confirm that UAH TLT vs GISS divergence is partly UHI induced."
that is an assumption on your part and is not backed by an analysis of the data to determine why there are similarities between TLT and surface data in north america and europe (where there are known UHI effects, known surface station siting problems, etc.) and why there are differences in africa and south america (where there are no measurements).
frank said, "Did this help?"
no. again the 1200km smoothing by giss is a major factor. you assume the diffrences in africa and south america are caused by population growth. but if you look at the map bob provided in his post, there is no data in those areas
frank said, "Example: Lets say we have 10 typical GHCN (GISS) station in 10 African towns of varying size and this data is then projected in 1200 km radiusses. The infilling of GISS 1200 km will then represent the temperature of cities in rural areas as if rural areas had city trends.
these are all assumptions. did you perform an analysis of these areas and their population growth?
frank said, "So the 1200 km range often used from cities makes it appears as if Sahara has CITY TREND, roughly speaking."
the sahara should not have a city trend. if the sahara has a city trend, then the difference that you're seeing is an error caused by the 1200km smoothing.
frank said, "Therefore, even when comparing SAHARA/GISS with UAH trends, to some degree you are comparing African city trends with UAH that is almost free of city heat."
without a detailed analysis this is an assumption.
frank said, "Therefore IF the city warming trends are warmer than rural sites, this should be possible to roughly evaluate by comparing (GISS ahara) with (UAH Sahara)."
no, for all of the reasons discussed above.
frank said, "I must make you guys aware, that the views im representing is pretty much rather mainstream sceptic viepoints on UHI, please read all UHI articles on Climate Audit, and you will see..."
nothing at the posts you linked support your guesses that the difference between TLT and surface temp over africa and brazil is caused by population growth. those are your assumptions and yours alone. you can't defer to other posts that do not support your claims and expect anyone to believe what you've written.
|- and more to "unkown" on 1200 km giss||By Frank Lansner on 18th January, 2011 at 12:49:33|
|I thought, maybe your point is about what Tisdale writes in hes splendid 2009 article where he compares UAH and GISS?
The discussion i had with Bob was in comments recently, for example:
"the vast majority of the difference between TLT and surface data exists in only one area of the globe. All areas would be impacted by UHI if it had a significant effect, but they are not. And that fact alone contradicts your claims that UHI is the primary reason for the difference between surface and TLT data.
If you had performed a reasonable analysis, Frank, you would have discovered that GISS land surface data for much of the United States has a lower trend than the TLT data:
(His graph definetely show UAH TLT vs GISS to be very SIMILAR for USA)
To that i just add, that
1) There is no UHI measured in USA by McIntyre/Peterson, so its wrong to expect UHI to come out of a UAH TLT vs GISS compare.
2) USA has much smaller relative population graowth rate compared to Africa or Brazil (!) so the fact that Bob Tisdale actually finds the UAH TLT difference over Africa and Brazil just seems to somewhat confirm that UAH TLT vs GISS divergence is partly UHI induced.
Did this help?
|To "unknown..."||By Frank Lansner on 18th January, 2011 at 11:40:53|
|ARGH i have to talk with my companion about improving this forum to enable normal debate so you dont have all these unknowns.
You write: "As noted earlier on this thread, you could be confusing the effects of infilling (1200km smoothing) for the effects of a growing population.
Also, if the population of a country is growing but they are growing in areas without urban development, then you are not seeing UHI."
Well i tried to answer ealier :-)
Example: Lets say we have 10 typical GHCN (GISS) station in 10 African towns of varying size and this data is then projected in 1200 km radiusses.
The infilling of GISS 1200 km will then represent the temperature of cities in rural areas as if rural areas had city trends. So the 1200 km range often used from cities makes it appears as if Sahara has CITY TREND, roughly speaking.
Therefore, even when comparing SAHARA/GISS with UAH trends, to some degree you are comparing African city trends with UAH that is almost free of city heat.
Therefore IF the city warming trends are warmer than rural sites, this should be possible to roughly evaluate by comparing (GISS ahara) with (UAH Sahara).
Dear Unknown, let me know if something is not clear, or if you think somethings completely wring in my arguments.
I must make you guys aware, that the views im representing is pretty much rather mainstream sceptic viepoints on UHI, please read all UHI articles on Climate Audit, and you will see ;-)
I reccomend my favourites:
and there are many others.
its the climate Audit / Peterson USA UHI i show here:
|more actual UHI results||By Frank Lansner on 18th January, 2011 at 11:22:11|
|(Or that is "change-in-UHI" results) :
Jones et al concludes approximately 0,53 K UHI pollution in warming trend across China for the period 1951 - 2004 - or "0,1K per decade" in the period.
And here from East Canada
QUOTE from the East Canada reseach:
No temperature rise outside Urban area !!
California reasearch due change in warming trends due to UHI:
- In the South Korea research, the graphs shows CITY minus RURAL, that is the warming trend induced by growing cities:
(Seoul the old capital has significant lower UHI than the other growing cities.)
|Frank replied||By Unknown on 18th January, 2011 at 11:18:59|
|You replied, "And then its BAFFLING that all continents actually show a UHI trend from this method that happends to fit rather well with population growth rates."
As noted earlier on this thread, you could be confusing the effects of infilling (1200km smoothing) for the effects of a growing population.
Also, if the population of a country is growing but they are growing in areas without urban development, then you are not seeing UHI.
|How to measure UHI or rather, changes in UHI:||By Frank Lansner on 18th January, 2011 at 09:27:34|
|(First: We have to fix it so not so many readers are "unknown"..!)
To measure the warming error of UHI, changes in UHI: You normaly compare a long row of average city temperatures with nearby rural areas. This accounts for the total warming pollution from the cities - even if UHI is related to population growth or related to more energy use or darker roads or any other city effect.
Like in gran Canyon vs Tuscon:
and then USA as a whole 1901-84:
Phil Jones did such compares for China over the years 1951-2004 and got around 0,53 K of related extra warming trend for China simply related to UHI. Or this is 0,1 K per decade.
We have to remember that the global warming as a whole is supposed t be around 0,7K for 100 years..
But its a fluffy affair.
But IF UHI is an important size in global temperatures, then the approach the above article simply has to work!
The UAH TLT is very little impacted by cities, very much impacted by rural areas (!) so UAH HAS to show a rather "rural result" thats the whole idea!
But GISS ground based is very often taken from smaller, medium, larger cities or airports - so GISS HAS to have som city trend! Unless corrected too much.
So a compare UAH vs GISS has a function to some degree to show the trend difference, rural vs urban. In fact (!) If there had NOT been a trend difference UAH - GISS i would have had to accept, that the UHI problem in temperature data was not as big as i thought.
.. Because I would not be able to explain that. If you cant measure a warmer city-groundbased temperature trend than the general mostly rural UAH trend, then its hard to argue for UHI as a significant problem or temperature data.
So not only is the UAH-GISS compare a kind oftest of UHI in temperature data, it also indicates an UPPER limit to UHI. And perhaps this upper limit for UHI is not as big as some sould have guessed.
So far results however are only so ROUGH that we can see a major match between UAH-GISS divergence on one hand and population growth on the other hand. This compare above mostly serve to conclude that we CANNOT rule out UHI as at least a part of the explanation of why GISS groundbased as more warming trend than UAH satellite data.
And then its BAFFLING that all continents actually show a UHI trend from this method that happends to fit rather well with population growth rates. If you check out many articles at Climate Audit, you will learn, that UHI should be a function of logatrithmic population growth.
And ... so far at least data from UAH-GISS compare actually confirms the theory allthough we only have rough data for now.
|Frank's reply||By Unknown on 18th January, 2011 at 04:52:32|
|You wrote, "What we look for is changes in UHI..."
And how do you plan to measure this? A city that has existed longer than TLT measurements can easily have an increase in UHI effect. Most cities use more electricity now than they did in the 1970s. Everyone has more electrical gadgets. There's more air conditioning. etc.
|Hi again Bob||By Frank Lansner on 18th January, 2011 at 00:34:52|
|You write: "Does UHI exist in the USA? Of course it does. Anyone who has walked from the west side of Manhattan to the east side on a summer day can tell you that"
Agree, no one denies the permanent UHI that makes cities warmer than surroundings, even alarmists and NASA agree on this.
What we look for is changes in UHI, Only changes in UHI will be a problem for temperature measurements over a period. And changes in UHI comes mostly from areas with the most explossive relative population growth. So to avoid more misunderstandings: When I (and many others) speak of UHI in temperature trends, its allways the CHANGE of UHI only. Permanent UHI as in London has no warming trend.
|Error In Frank’s reply:||By Unknown on 17th January, 2011 at 23:59:46|
|Frank replied, “And this time i agree, you did not say that there would be UHI in USA etc in your article.”
Wrong. You have once again misrepresented what I said. I said nothing about UHI in that post. It was never mentioned.
Does UHI exist in the USA? Of course it does. Anyone who has walked from the west side of Manhattan to the east side on a summer day can tell you that, with a westerly wind, the temperature change from west to east is easily 3 deg F.
A recent post at WUWT provided documentation of UHI in the USA:
The article stated, “Summer land surface temperature of cities in the Northeast were an average of 7 deg C to 9 deg C (13 deg F to 16 deg F) warmer than surrounding rural areas over a three year period, the new research shows. The complex phenomenon that drives up temperatures is called the urban heat island effect."
|Hi Bob! Thanks for commenting.||By Frank Lansner on 17th January, 2011 at 23:24:04|
|And this time i agree, you did not say that there would be UHI in USA etc in your article.
It is my impression - that your main argument against UAH-GISS differences as partly "UHI indicator" was that IF any UHI should have been indicated by this approach, THEN this should have been visible in USA, Europe etc much more than Africa etc. And because the UAH-GISS approach did not support this expectation, then you appeared not to believe in the possibility of UAH-GISS partly as an "UHI indicator".
Bob, I need not do more out of this, i just hope that we sceptics can continue having a good fruitful coorporation. Im aware than from your point of view, I have been very slow to agree with you on some things. But as a true sceptic i have to question things, hope you understand. Some alarmists have a hard time with me too .... !
|Reply to Unknown on 17th January 2010||By Unknown on 17th January, 2011 at 19:59:04|
|You wrote, “If Bob claims that UHI 1979-2009 should.. be USA, Canada, Europe, Sibria then HE should show that this is true!!!! And after the above article, i think Bobs gonna have a hard time doing so!!!!”
I did not make any claims about UHI effects in USA, Canada, Europe or Siberia. The author of this post, Frank Lansner, did.
In my post that Frank linked…
...I showed that the surface temperature and TLT linear trends for Central North America from 1979 to 2009 were similar (GISS slightly less):
and I showed that surface temperature and TLT linear trends for Northwest North America from 1979 to 2009 were similar (GISS slightly less):
and I showed that surface temperature and TLT linear trends for portion of Europe from 1979 to 2009 were similar (GISS slightly higher):
and I showed that surface temperature had a significantly higher trend than TLT linear trends for portion of Siberia:
Again, my post had nothing to do with UHI. I am not responsible for any assumptions that he makes about what the data does and does not show.
|If Bob claims that UHI 1979-2009 should..||By Unknown on 17th January, 2011 at 14:06:30|
|be USA, Canada, Europe, Sibria then HE should show that this is true!!!! And after the above article, i think Bobs gonna have a hard time doing so!!!!
|Hi unknown :-)||By Frank Lansner on 17th January, 2011 at 13:55:46|
|You write: "if giss is usiing 1200km smoothing in those regions then there are no weather stations. if there are no weather stations, are there cities? if there are no cities, how can there be urban heat islands?"
But the 1200 km smoothing comes from areas with smaller or bigger civilizations normally. It is not unusual for an African city to go from for example 50.000 people in 1979 to 250.000 people in 2010. In Europe cities only changes size in some % over those 30 years, therefore its hopelessly wrong to think UHI should come expecially from Europe 1979-2009.
This is important because this mistake is apparantly the main argument in some peoples argumentation agains UHI in global temperatures all together.
K.R. Frank Lansner
PS: Down under, thanks for comment!
|GISS 1200 km smoothing||By Unknown on 17th January, 2011 at 11:49:30|
|Many long timeseries even from areas in the world with smaller urbanisation, they taken from smaller or bigger towns. And especially in for example a smaller, medium town in Africa, the population has often exploded. Therefore specifically when we talk 1979-2009m the satellite years, we should no longer expect UHI to be most visible in the areas where urbanisation was already large in 1979.
GISS 1200 km smotthing is taken from places from a little civilization, normally towns, which in Africa has grown faster than other places.
GISS (GHCN) do not have their stations standing in the sand of Sahara :-) No , they represent a fast growing civilization/population.
So Tisdales opinion is based on a belief that UHI 1979 - 2009 should be in for example USA rather than Africa. But it is just wrong, and sometimes its the messenger who gets killed... !
|uhi or giss 1200 km smoothing||By Unknown on 17th January, 2011 at 11:11:58|
|i think bob tisdale's post showed that the grids with the biggest differences are where giss uses the 1200km smoothing. if giss is usiing 1200km smoothing in those regions then there are no weather stations. if there are no weather stations, are there cities? if there are no cities, how can there be urban heat islands?|
|Review of this article says OK for overall principle!||By Frank Lansner on 17th January, 2011 at 00:08:31|
|To our readers.
I have had the present article to review by a most important "sceptic" world wide, and the concept of this article appears to yet again be generally confirmed.
I here quote a central line from the review:
"The original Oke formulation of UHI was as a function of log(population) – a point made in a number of XXX posts i.e. UHI increase was proportional to the % change in population, not to population. "
And this is the point and procedure of the above article: Use relative population growth when estimating where UHI should be highest.
Hoever, i have not YET - used the most optimal Oke / log(population) which is however obviously rather close to the relative population growth i used above.
I will treat my reviewer anonymous as this is his policy. But to him i say: Thankyou of all my heart for review and valuable info.
|Hi Frank||By Unknown on 16th January, 2011 at 21:08:25|
|Correct me if im wrong, but is not UHI proven irrelevant??
Or at least now im not so sure, GReat Work UHI is bACK!!!!
- Down Under