Tired of build-a-volcano junior high science fair projects, my son and I tried to identify something he could easily do himself (well, mostly, you know how kids science projects are) but that would actually contribute a small bit to science. This year, he is doing a project on urban heat islands and urban biases on temperature measurement. The project has two parts: 1) drive across Phoenix taking temperature measurements at night, to see if there is a variation and 2) participate in the surfacestations.org survey of US Historical Climate Network temperature measurement sites, analyzing a couple of sites for urban heat biases.
The results of #1 are really cool (warm?) but I will save posting them until my son has his data in order. Here is a teaser: While the IPCC claims that urban heat islands have a negligible effect on surface temperature measurement, we found a nearly linear 5 degree F temperature gradient in the early evening between downtown Phoenix and the countryside 25 miles away. I can’t wait to try this for myself near a USHCN site, say from the Tucson site out to the countryside.
For #2, he has posted two USHCN temperature measurement site surveys here and here. The fun part for him is that his survey of the Miami, AZ site has already led to a post in response at Climate Audit. It turns out his survey adds data to an ongoing discussion there about GISS temperature "corrections."
Out-of-the-mouth-of-babes moment: My son says, "gee, dad, doesn’t that metal building reflect a lot of heat on the thermometer-thing." You can bet it does. This is so obvious even a 14-year-old can see it, but don’t tell the RealClimate folks who continue to argue that they can adjust the data for station quality without ever seeing the station.
This has been a very good science project, and I would encourage others to try it. There are lots of US temperature stations left to survey, particularly in the middle of the country. In a later post I will show you how we did the driving temperature transects of Phoenix.
Update: Here is the temperature history from this station, which moved from a more remote location away from buildings about 10 years ago. I am sure the recent uptick in temperatures has nothing to do with the nearby building and asphalt/black rock ground cover. It must be global warming.
Getting young people to do science is great, but please don’t mislead them about previous results. You say that the IPCC claims that urban heat islands have a negligible effect on surface temperature measurement, and then say you’ve found urban heat islands. Well, no-one, absolutely no-one claims that urban heat islands do not exist. What is well known is that while they exist, they do not bias the surface temperature record because their effect is corrected for.
The choice you give readers in situations like this is between believing that you simply haven’t read the literature, or believing that you are deliberately trying to mislead people.
For reference, here’s the IPCC’s summary, from page 237 of the report of WG1:
Urban heat island effects are real but local, and have not biased the large-scale trends. A number of recent studies indicate that effects of urbanisation and land use change on the land-based temperature record are negligible (0.006ºC per decade) as far as hemispheric- and continental-scale averages are concerned because the very real but local effects are avoided or accounted for in the data sets used. In any case, they are not present in the SST component of the record. Increasing
evidence suggests that urban heat island effects extend to changes in precipitation, clouds and DTR, with these detectable as a ‘weekend effect’ owing to lower pollution and other effects during weekends.
RW – The sentence you use as evidence for your point of view is exactly the point being contested (begging the question). Put simply, you say that UHI effects don’t matter in the meta-analysis because the data input is corrected for these. The point being made is that at least some, probably many, and quite possibly most, of the “rural” stations used to provide the “corrections” to the “urban” station measurements are themselves subject to microclimactic conditions that have upward biases as well.
The surfacesstations.org proect is designed to collect evidence of the siting of the stations in both rural and urban locations such that any systematic biases can be more appropriately measured.
Finally, in the published datasets, there is little documentation as to how the values of the correction factors are obtained. Without this information, it is impossible to judge if the data sets feeding into the models are themselves valid. The first principle of computer modeling sums this up nicely – “Garbage in, Garbage out”.
No, what was being claimed was that the IPCC denies that heat islands exist, and that the budding young scientist would disprove this by detecting a heat island. Well, the IPCC doesn’t say anything of the sort and nor does anyone else.
You say the point being made was about rural stations. Strange. I’m not from the US so I could be mistaken, but isn’t Phoenix a rather large city? If you drive across Phoenix taking temperature measurements at night, to see if there is a variation, it would be astonishing if there wasn’t a variation. It’s a nice little experiment to measure it, and if it is measured so clearly that’s good for the budding scientist, but it doesn’t tell us anything new.
How can urban heat islands be polluting the temperature record from sea surface temperatures, glacier recession, lake ice break-up and boreholes? And how can urban heat islands possibly be making the Arctic warm faster than anywhere else? This paper should put anyone’s mind to rest on urban heat islands, unless they’ve already decided that whatever happens they won’t believe in global warming.
And if you read pretty much any paper about the surface temperature record, it will tell you how they corrected for urban heat islands. Try this one, for example. Section 4.2.2 has the details. Actually, they even specifically mention that Phoenix causes a very strong urban heat island, so the claim that anyone’s ever said heat islands don’t exist is totally wrong.
Is there any way to look up the exact GISS correction factor used for this particular station?
RW – you are missing the point.
UHI is simply one of many factors which render the surface record highly suspect. The measurements of polar temperatures are based on extremely limited sets of data. The sea surface temperatures also have very poor coverage and have numerous ‘adjustments’ applied to deal with undocumented changes in the measuring technique. Pointing to glaciers as evidence of warming is a red herring since most of these glaciers have been melting for 200 years. More importantly, material disgorged at the end of these glaciers provides evidence that they receded further during the MWP.
When it comes to the GISS UHI adjustments I suggest you look at the latest example of data fudging: http://wattsupwiththat.wordpress.com/2008/02/17/cedarville-and-giss-adjustments/
As you can see, the wizards of GISS have taken a well sited rural site and ‘corrected’ the data to turn a cooling trend into a warming trend.
The problems with the GISS polar record can be made painfully obvious if one plots the data with a polar projection here:
http://www.climateaudit.org/?p=2721#comment-213085
One could walk a 10m circle around the poles and walk through 4 completely different climates! Why should anyone believe that the GISS polar temperatures have any connection to reality?
Frankly, I don’t see how anyone can defend a surface record which includes those kinds of fudges. We are lucky that Anthony was able to find some sites that demonstrate the manipulation extremely clearly. I suspect similar manipulation permeates the entire record but it is impossible to prove.
RW – From the very document you cite:
“The urban adjustment of Hansen et al.
[1999] consisted of a two-legged linear adjustment such that the linear trend of temperature before and after 1950
was the same as the mean trend of rural neighboring stations. In the new GISS analysis the hinge year is a variable
chosen to be that which allows the adjusted urban record to fit the mean of its neighbors most precisely.”
I am not arguing that UHI does not exist. What I am arguing is that the methods used to “correct”/”adjust”/”normalize”/”fudge” it out of the data input into models is at best suspect, and at worst outright fraudulent. If the trends at the “rural” neighboring stations, some of which have been found to be sited in asphalt parking lots, is not unbiased, then the whole UHI correction scheme is not worth a wheelbarrow of dead carp.
There is little in Hansen’s methodology that is at odds with the hypothesis that he is manipulating the data arbitrarily to provide the result he wishes to obtain.
No, the claim made was that the IPCC thinks that heat islands do not exist. You seem to be trying to second-guess what the author actually meant to say. Read the post.
Did you know that the extent and thickness of Arctic sea ice has been diminishing for thirty years? Did you know that the proportion of ice more than five years old in the Arctic has decreased by two thirds over the past twenty years? Did you know that glacier recession is currently accelerating? Are you aware of any published instrumental global temperature record which does not show warming? Do you think that every single scientist in the field is guilty of fraud?
RW, “While the IPCC claims that urban heat islands have a negligible effect on surface temperature measurement” != “The IPCC claims that urban heat islands don’t exist.”
You fail English. Again.
Adirian – you’re an idiot.
In the sentence While the IPCC claims that urban heat islands have a negligible effect on surface temperature measurement, we found a nearly linear 5 degree F temperature gradient in the early evening between downtown Phoenix and the countryside 25 miles away, how does the second part contradict the first? You could only think it did if you thought the IPCC said that heat islands don’t exist. Do you somehow think that the point of my post was not to say exactly what you’ve just said to me, as if it was some kind of clever insight on your part?
RW states, “Are you aware of any published instrumental global temperature record which does not show warming?” Of course. The far southern hemisphere (-70 to -60 latitude) which clearly shows a cooling trend over the past 29 years http://www.remss.com/pub/msu/monthly_time_series/RSS_Monthly_MSU_AMSU_Channel_TLT_Anomalies_Land_and_Ocean_v03_1.txt
Keith – that is not a global temperature record.
RW – Apologies. You are correct. I was simply trying to point out that although the Arctic has seen warming for the past several years (largely corrected by this cold winter), the Antarctic has actually seen cooling for the past 30 years and is currently above the 1979-2000 mean for ice cover. http://arctic.atmos.uiuc.edu/cryosphere/
RW,
You must have worthwhile things to address that don;t involve argueing against postions that you think others have. The post specificly says “While the IPCC claims that urban heat islands have a negligible effect on surface temperature measurement”. You turn this into assuming that one he must really mean that he believes the IPCC doesn’t believe that UHI’s exist. No skeptic believes that the IPCC denys the existence of UHI’s. We just think that they don’t correct adequately (or correctly) for their existence. So, let’s argue about that.
Oh, and the global satellite temperature data does show no warming for the past several years.
Again I quote: “This
implies that even though a few stations, such as Tokyo and Phoenix, have large urban warming, in the typical case,
the urban effect is less than the combination of regional variability of temperature trends, measurement errors, and
inhomogeneity of station records.”
My understanding of this sentence is that when you look at all of the other factors that influence temperature variability, in the great majority of cases, it is impossible by my methiod to determine the magnitude and direction of any UHI effects. Coyote Jr.’s experiment demonstrates that such effects can be readily measured by simple techniques. (In the words of one of my professors, “That’s what graduate students are for”)
It is perhaps unfortunate that Coyote happens to live in one of the cities where a UHI effect was discernable in Hansen’s data. The obvious follow on is to determine if similar patterns can be measured in urban areas where Hansen was not able to discern a trend.
Secondly, the surfacestations.org project is designed to determine if the criteria used to separate “urban” and “rural” is valid. As others have stated, it appears that there is a warming bias in the locations selected for even the “rural” stations. Since the “urban” stations are adjusted to match the “rural” trends, any effect on the microclimate at the “rural” stations caused by increasing population effects (more pavement, more buildings to interrupt wind flow, airconditioning vents, etc.) gets amplified in the final series when the assumption is that they are being dampened out.
Again I quote: “This
implies that even though a few stations, such as Tokyo and Phoenix, have large urban warming, in the typical case,
the urban effect is less than the combination of regional variability of temperature trends, measurement errors, and
inhomogeneity of station records.”
My understanding of this sentence is that when you look at all of the other factors that influence temperature variability, in the great majority of cases, it is impossible by my methiod to determine the magnitude and direction of any UHI effects. Coyote Jr.’s experiment demonstrates that such effects can be readily measured by simple techniques. (In the words of one of my professors, “That’s what graduate students are for”)
It is perhaps unfortunate that Coyote happens to live in one of the cities where a UHI effect was discernable in Hansen’s data. The obvious follow on is to determine if similar patterns can be measured in urban areas where Hansen was not able to discern a trend.
Secondly, the surfacestations.org project is designed to determine if the criteria used to separate “urban” and “rural” is valid. As others have stated, it appears that there is a warming bias in the locations selected for even the “rural” stations. Since the “urban” stations are adjusted to match the “rural” trends, any effect on the microclimate at the “rural” stations caused by increasing population effects (more pavement, more buildings to interrupt wind flow, airconditioning vents, etc.) gets amplified in the final series when the assumption is that they are being dampened out.
RW:
It is arguments and approaches that AGW Advocates have made and used that have prompted me to evolve from an Acceptor of AGW proclamations to a Skeptic.
In case there is any sincerity in your desire for clarification, I will try the following:
1. I know of no Skeptic who believes that the IPCC denies the existence of UHIs.
2. There appears to be legitimate questions on whether the providers of temperature trends adequately handle the issue of UHI, etc. (The builders of the Titanic were reported to have built an unsinkable ship, but a simple audit of the design would have revealed otherwise.) The ability of various skeptics to accept the reported temperature trends has been hampered by many factors; and one of those factors has been the lack of transparency on the adjustments. My kudos to you if you have been able to run and analyze the adjustment methodology used by GISS, but I have not been able to do so. I can see read the differences between raw data and adjusted data, but I cannot follow the algorithm for the adjustment, and the results are puzzling to say the least.
3. I know of no Skeptic who claims that overall global are not higher now than they were two or three hundred years ago. Glacial retreat started long before CO2 emissions were significant. If you need references from NASA and other sites to see this, I am sure we can help you find these sites.
4. Even if glacial retreat started earlier than significant CO2 emissions, AGW still could be a problem to address. To get a good handle on if it is a problem, we need data that is not suspicious. To view questions on data adjustments as heresy simply adds credence to the Skeptics and undermines the credibility of AGW proponents.
People seem to think that no-one would deny that heat islands are a well known effect. II’ll quote again: While the IPCC claims that urban heat islands have a negligible effect on surface temperature measurement, we found a nearly linear 5 degree F temperature gradient in the early evening between downtown Phoenix and the countryside 25 miles away. Why would you join these two statements in one sentence if you knew the IPCC is perfectly well aware of the existence of heat islands? You are all putting words into the mouth of the author of this blog, who is remaining conspicuously silent.
So, An Inquirer, this very post shows you that there is one sceptic who believes that the IPCC denies the existence of urban heat islands. In contrast, I know of no scientist who thinks that CO2 is the only thing controlling the climate (as you seem to imply). I also know of no plausible explanation of the current rapid warming that doesn’t involve the warming effect of 100ppm extra CO2 since 1850.
RW, so, let’s make this perfectly clear with big easy to read letters, since you seem to have trouble with comprehension:
FIVE DEGREES IS _NOT_ NEGLIGIBLE. THE SECOND SENTENCE DOES NOT CONTRADICT THE FIRST, IT ELABORATES UPON IT.
And persistence doesn’t make you any less the idiot; not knowing another explanation is not proof of the first. A thousand years ago nobody knew any other explanation for the origins of life than that of divine intervention.
RW – As loath as I am to continue to feed an apparent troll, I would like to answer one of your comments:
“I also know of no plausible explanation of the current rapid warming that doesn’t involve the warming effect of 100ppm extra CO2 since 1850.”
May I offer
1. Changes in solar irradiance
2. Changes in cosmic ray flux, which affect water droplet formation and cloud nucleation
3. Periodic or even chaotic shifts in ocean circulation patterns
4. Changes in land use patterns as forests are changed to grass and cropland, and in some cases back again
5. Natural methane emmissions from carbonate ices
Let’s also not lose sight of the fact that the true argument is not over whether the average temperature of the Earth will rise two degrees or 2.5 degrees. The argument is over what the costs of changing the trend are, and whether or not they exceed the benefits to be gained.
For example, If the cost of the food I eat goes up a dollar a day, I may notice it in some vague way, but it will not affect my life to any great
extent. However, to a large portion of the Earth’s human population, that dollar a day would mean the difference between sufficiency and hunger.
Warming deniers are so blinkered and stupid that they think anyone pointing out facts that don’t fit their beliefs is a troll? Well fine, you believe what you want to believe, and don’t let yourself be troubled by facts, but your five offers are all implausible. The last three are pure fiction, and the first two would work if a decline in solar irradiance and activity could somehow heat the world. Can you offer an explanation of how that would work?
Yes, you’re right about the true argument. The problem is that while it’s obvious that rapid warming is very bad (eg 35,000 death in Europe’s heatwave of 2003, increasing strength of hurricanes, disruption of water supply due to glaciers disappearing, etc etc etc), there are people who deny that any warming is taking place, who try to suggest that the IPCC doesn’t even know about urban heat islands and so can’t be trusted, who if they accept that any warming is taking place, deny humankind’s involvement, and who even say that actually warming will be good for us all. And on the evidence of this blog and most people posting here, there is not a single piece of evidence that will shake people from these views, which they have adopted for political reasons, not scientific.
RW – You’re a troll because you have open contempt for the entire opposition. This is distinct from the open contempt, say, that I have for you. You don’t argue the facts, you don’t argue the evidence, you argue the language – this is troll behavior. And you do it persistently. You don’t admit when you’re wrong, you don’t back down, and you refuse to admit that there is anyone on your side who deserve the criticism they’re receiving.
Let’s take your points in one by one.
First, who here is denying that warming has taken place? There’s considerable debate about how much, and when, but nobody is claiming that climate is static.
Second, nobody, in spite of your fervent wishes, has claimed that the IPCC doesn’t know about UHI. We’ve been over this, and you seem to have a reading comprehension problem.
Third – hey, you’re grouping. Wildly and erratically. Which shouldn’t be surprising, since you’ve shown you aren’t that good at statistics. So let’s de-group, shall we?
You have the people who accept warming is taking place – everyone here, basically – who… deny human involvement? No, nobody has done that. They’ve debated the DEGREE of human involvement. I/e, if climate changes have happened in the past, and we don’t have the information on what caused them or to what extent any of the variables had – to what extent can we determine precisely how much of the current warming trends are attributable to human influence?
Then you have – a completely different group – those who say warming will be good. Actually, I don’t see them, what I see here are people who say that the economic damage resulting from interference will be worse than the heating which would otherwise take place.
And speaking of evidence that would shift people from their views – what, exactly, would shift you from yours? Say, conclusive proof that the temperature records for the past century are heavily biased? What about proof that the historic link between CO2 and temperature doesn’t have causality link that was assumed when the models you defend were developed? Or historic proof that high CO2 levels are not sufficient even to sustain high temperatures, much less produce them?
All this evidence exists. So what’s the magic piece of evidence that would make you realize – hey, there is good reason to be SKEPTICAL. To regard the claims as UNPROVEN. Nobody here denies AGW – the position is, as hard as this is for you to understand, THAT IT IS UNPROVEN. That IS the true argument taking place here, and until you wrap your head around at the very least the difference between skepticism and denial, you’ll just serve as amusement to the rest of us.
It’s easy to divorce political and scientific, incidentally – it’s just this easy: Cocaine hurts people. That’s the science question, and, unlike climate, it is pretty well proven. The political question is whether or not to ban it. And, you see, it’s a completely different question. The political and scientific questions here are also different, and it is your presumption that they are the same, not ours.
Adirian – you are not worth discussing anything with. Remember what the first thing you said to me was? I’ll remind you if you like. You said RW – you’re an idiot. I rather think that makes you a troll. So, no more feeding. I will ignore any further posts from you.
I find it bizarre that the author of the blog never ever responds to any comments left, but seems to have accrued a bunch of yapping supporters who have appointed themselves as interpreters and clarifiers of what he is trying to say. Rather than let idiots like adirian assume they know what he meant, maybe it would be really useful if he could explain what he thought the IPCC said, and how exactly his measurement of the very well known urban heat island effect caused by Phoenix ‘contributes a small bit to science’.
I remember quite well. Still hold that opinion, in point of fact. The difference between you and I is that I came to that conclusion based on your behavior towards other members of the forum, and you have come to that conclusion regarding everyone on this forum because they disagree with you. If you’ll also recall, I stepped in because of your trollish behavior towards another member of the forum; Raven, specifically. And whatever you think, you don’t hide your opinions any better than I do, in spite of the fact that I’m up front and honest about them.
“Troll,” incidentally, got its name from “trolling,” which is, loosely described, net fishing. Trolls are people who say inciteful things to start meaningless arguments and derail the main argument of a thread – the inciteful behavior being the net, with which they’re attempting to catch the thread, or the participants within it, whichever you prefer. My behavior is closer, in fact, to “flaming.” That is, attacking another forum member. You’re the troll, because you derail arguments with petty and meaningless linguistic debates. I’m the flamer, because I attack you afterwards. (This post, incidentally, might qualify as trolling – calling you an idiot certainly doesn’t.)
Lots of arguments about whether UHI exists, if it does exist then how large is it, how it can be or is being corrected. Lots of fancy words and quotes. So tell me, where is the published operating procedure that discusses the experiments that have been done and the proper algorithms to account for UHI? I would like to read some technical papers that discuss how this has been physically tested, and how the calculations for correction have been derived from those physical tests.
Seems like this kid and his dad are doing more real science than Hansen does. Playstation Climate Modeling is one thing, but going out and getting your hands dirty is where it all starts. No data points, no models.
Janice:
A. Both the anti-AGW and pro-AGW blogs have cited several UHI papers.
B. You can also do an internet search or go to the library.
C. Read the Hansen papers and see what they cite in the footnotes as seminal studies.
D. CS refers to a paper that he looked at to design the transect study.
E. Please drop the tone of needing everything spoonfed to you and being upset that it wasn’t done yesterday. It makes us skeptics (I r one) look bad.
Is it so hard to split the sites Urban/rural then plot them individually, that should indicate a bias or not.
Steve McIntyre of climateaudit has done this see link below.
http://aycu26.webshots.com/image/48825/2003305333281076257_rs.jpg
Both plots level out at or around 1998.
Most of the sites are now Urban and have been for the last 10 years or so therefore the ground temps for those last 10 years and all future years should not have a warming UHI bias.
We may see over the coming years little or no temperature increase if the UHI effect was real.
Reference urban/rural,
sorry link did not work.
http://aycu26.webshots.com/image/48825/2003305333281076257_rs.jpg
try this link.
http://www.climateaudit.org/?p=1859
RW says,
Urban heat island effects are real but local, and have not biased the large-scale trends. A number of recent studies indicate that effects of urbanisation and land use change on the land-based temperature record are negligible (0.006ºC per decade) as far as hemispheric- and continental-scale averages are concerned,
I believe that there are NO weather stations in the deserts, deserts cover 14% of the planets land mass, there were NO weather stations in the oceans that is until recently, other than the odd sailor throwing a bucket over the side of a ship, Oceans cover 70% of the planet, his means only 16% of the planet has been covered by weather stations since the early 1900`s and most of these were and still are in the western hemisphere. The US covers 2% of that 16%, that`s quite large, Brazil I believe has less than a dozen, that`s not many for its size.
Every study that has looked at individual city stations and their immediate rural stations sees an urban bias of up to 2 degrees C, its only the likes of Jones and Peters that discount this as trivial.
What appears clear to me is that from around 1900 to 1998 there has been a rise in temperatures seen by the ground stations, this rise in temps has been caused I believe by the steady conversion of the predominantly rural stations (cool stations) around 1900 to predominantly URBAN (warm stations)in 1998. I believe this accounts for at least 0.4 of the rise seen over that time and that rise is NOT associated with CO2.
I also believe that the UHI effect even though it is real will no longer effect global temps as already said the vast majority of these stations are now URBAN,(they are all in high temperature areas and measure only the immediate surrounds of where the station is situated) the few rural stations left will have NO impact on the overall trend.
Agw has occurred but was caused NOT by CO2 but by the misinterpretation of the ground station data by misguided individuals such as Hanson,Jones and Mann. The only impact UHI can now have on global temps is through India and China who are still in the process of urbanisation. Do the same team that fiddle the ground data fiddle the satellite date, hasn`t the satellite data been aligned with the dodgy ground temps.
Example: Is massive UHI warming in China distorting Jones et al gridded T data ?
http://www.warwickhughes.com/blog/?p=45
The Jones et al 1990 Letter to Nature: a rebuttal of some key points.
http://www.warwickhughes.com/papers/90lettnat.htm
Urban warming effects in China by Ren:
Abstract:
Temporal change in urbanization-induced warming at two national basic meteorological stations of China and its contribution to the overall warming are analyzed. Annual and seasonal mean surface air temperature for time periods of 1961~2000 and 1981~2000 at the two stations of “Beijing and Wuhan Cities and their nearby rural stations all significantly increase. Annual and seasonal urbanization-induced warming for the two periods at Beijing and Wuhan stations is also generally significant, with the annual urban warming accounting for about 65~80% of the overall warming in 1961~2000 and about 40~61% of the overall warming in 1981~2000. This result along with the previous researches indicates a need to pay more attention to the urbanization-induced bias probably existing in the current surface air temperature records of the national basic stations”.
http://climatesci.org/2007/03/16/two-papers-on-the-urban-heat-island-effect-on-temperatures/