UHI is alive and well

One of the most ridiculous claims recently related to Menne et al 2010 and my surfacestations project was a claim made by DeSmogBlog (and Huffington Post who carried the story also) is that the “Urban Heat Island Myth is Dead“.

To clarify for these folks: Elvis is dead, UHI is not.

For disbelievers, let’s look at a few cases showing UHI to be alive and well.


CASE 1: I’ve measured it myself, in the city of Reno for example:


The UHI signature of Reno, NV  – Click for larger image

Read the story of how I created this graph here The procedure and raw data is there if you want to check my work.

I chose Reno for two reasons. It was close to me, and it is the centerpiece of a NOAA training manual on how to site weather stations to avoid UHI effects.


CASE 2: NOAA shows their own measurements that mesh well with mine:

To back that up, the NOAA National Weather Service includes the UHI factor in one of it’s training course ( NOAA Professional Competency Unit 6 ) using Reno, NV.

In the PCU6 they were also kind enough to provide a photo essay of their own as well as a graph. You can click the aerial photo to get a Google Earth interactive view of the area. The ASOS USHCN station is right between the runways.

reno-nv-asos-relocation.jpg

This is NOAA’s graph showing the changes to the official climate record when they made station moves:

reno-nv-asos-station-moves-plot.png

Source for 24a and 24b: NOAA Internal Training manual, 2004-2007

Oops, moving the station south caused a cooling. Fixed now, all better.

What is striking about this is that here we have NOAA documenting the effects of an “urban heat bubble” something that DeSmog Blog says ” is dead”, plus we have NOAA documenting a USHCN site with known issues, held up as a bad example for training the operational folks, being used in a case study for the new USHCN2 system.

So if NOAA trains for UHI placement, I’m comfortable in saying that DesmogBlog claims of UHI being “dead” are pure rubbish. But let’s not stop there.


CASE 3: From an embattled scientist.

A paper in JGR that slipped in 2007 without much notice (but known now thanks to Warwick Hughes) is one from Phil Jones, the “former” director of the Hadley Climate Center in the UK. The paper is titled:  Urbanization effects in large-scale temperature records, with an emphasis on China

In it, Jones identifies an urban warming signal in China of 0.1 degrees C per decade.  Or, if you prefer, 1 degree C per century. Not negligible by any means. Here is the abstract:

Global surface temperature trends, based on land and marine data, show warming of about 0.8°C over the last 100 years. This rate of warming is sometimes questioned because of the existence of well-known Urban Heat Islands (UHIs). We show examples of the UHIs at London and Vienna, where city center sites are warmer than surrounding rural locations. Both of these UHIs however do not contribute to warming trends over the 20th century because the influences of the cities on surface temperatures have not changed over this time. In the main part of the paper, for China, we compare a new homogenized station data set with gridded temperature products and attempt to assess possible urban influences using sea surface temperature (SST) data sets for the area east of the Chinese mainland. We show that all the land-based data sets for China agree exceptionally well and that their residual warming compared to the SST series since 1951 is relatively small compared to the large-scale warming. Urban-related warming over China is shown to be about 0.1°C decade−1 over the period 1951–2004, with true climatic warming accounting for 0.81°C over this period.

Even though Jones tries to minimize the UHI effect elsewhere, saying the UHI trends don’t contribute to warming in London and Vienna, what is notable about the paper is that Jones has been minimizing the UHI issues for years and now does an about face on China.

Jones may have tried to hide CRU data, but he’s right about China.


CASE 4: From “The Dog ate My Data” who writes:

The Australian Bureau of Meteorology (BOM) blames Melbourne’s equal warmest overnight temperature of 30.6 degrees, on January 12 on the heat island effect. The previous time the city was that hot overnight was February 1, 1902.

The Age newspaper cites a meteorologist at the bureau, Harvey Stern,

Melbourne recorded its equal warmest overnight temperature, 30.6 degrees, on January 12. The previous time the city was that hot overnight was February 1, 1902.

A meteorologist at the bureau, Harvey Stern, said that Melbourne suffered from a heat island effect, in which a city is warmer than the surrounding countryside.

This was the case especially at night, because of heat stored in bricks and concrete and trapped between close-packed buildings.

I am stunned if that is correct firstly because BOM isn’t blaming Global Warming and secondly that the urban heat island effect directly receives the blame. With faults in the 2007 IPCC’s AR4 now pouring out I guess it is not suprising that attributions of weather events are now, shall we say, possibly becoming more circumspect.


CASE 5: Heatzilla stomps Tokyo

From the website “science of doom” who writes:

New Research from Japan

Detection of urban warming in recent temperature trends in Japan by Fumiaki Fujibe was published in the International Journal of Climatology (2009). It is a very interesting paper which I’ll comment on in this post.

The abstract reads:

The contribution of urban effects on recent temperature trends in Japan was analysed using data at 561 stations for 27 years (March 1979–February 2006). Stations were categorized according to the population density of surrounding few kilometres. There is a warming trend of 0.3–0.4 °C/decade even for stations with low population density (<100 people per square kilometre), indicating that the recent temperature increase is largely contributed by background climatic change. On the other hand, anomalous warming trend is detected for stations with larger population density. Even for only weakly populated sites with population density of 100–300/km2, there is an anomalous trend of 0.03–0.05 °C/decade. This fact suggests that urban warming is detectable not only at large cities but also at slightly urbanized sites in Japan. Copyright, 2008 Royal Meteorological Society.

Why the last 27 years?

The author first compares the temperature over 100 years as measured in Tokyo in the central business district with that in Hachijo Island, 300km south.

Tokyo –               3.1°C rise over 100 years (1906-2006)
Hachijo Island –  0.6°C over the same period

Tokyo vs Hachijo Island, 100 years

This certainly indicates a problem, but to do a thorough study over the last 100 years is impossible because most temperature stations with a long history are in urban areas.

However, at the end of the 1970’s, the Automated Meteorological Data Acquisition System (AMeDAS) was deployed around Japan providing hourly temperature data at 800 stations. The temperature data from these are the basis for the paper. The 27 years coincides with the large temperature rise (see above) of around 0.3-0.4°C globally.

And the IPCC (2007) summarized the northern hemisphere land-based temperature measurements from 1979- 2005 as 0.3°C per decade.

How was Urbanization measured?

The degree of urbanization around each site was calculated from grid data of population and land use, because city populations often used as an index of urban size (Oke, 1973; Karl et al., 1988; Fujibe, 1995) might not be representative of the thermal environment of a site located outside the central area of a city.

What were the Results?

Temperature anomaly against population density, JapanMean temperature anomaly vs population density, Japan

The x-axis, D3, is a measure of population density. T’mean is the change in the mean temperature per decade.

Tmean is the average of all of the hourly temperature measurements, it is not the average of Tmax and Tmin.

Notice the large scatter – this shows why having a large sample is necessary. However, in spite of that, there is a clear trend which demonstrates the UHI effect.

There is large scatter among stations, indicating the dominance of local factors’ characteristic to each station. Nevertheless, there is a positive correlation of 0.455 (Tmean = 0.071 logD3 + 0.262 °C), which is significant at the 1% level, between logD3 and Tmean.

Here’s the data summarized with T’mean as well as the T’max and T’min values. Note that D3 is population per km2 around the point of temperature measurement, and remember that the temperature values are changes per decade:

The effect of UHI demonstrated in various population densitiesThe effect of UHI demonstrated in various population densities

Note that, as observed by many researchers in other regions, especially Roger Pielke Sr, the Tmin values are the most problematic – demonstrating the largest UHI effect. Average temperatures for land-based stations globally are currently calculated from the average of Tmax and Tmin, and in many areas globally it is the Tmin which has shown the largest anomalies. But back to our topic under discussion..

And for those confused about how the Tmean can be lower than the Tmin value in each population category, it is because we are measuring anomalies from decade to decade.

And the graphs showing the temperature anomalies by category (population density):

Dependence of Tmean, Tmax and Tmin on population density for different regions in JapanDependence of Tmean, Tmax and Tmin on population density for different regions in Japan

Quantifying the UHI value

Now the author carries out an interesting step:

As an index of net urban trend, the departure of T from its average for surrounding non-urban stations was used on the assumption that regional warming was locally uniform.

That is, he calculates the temperature deviation in each station in category 3-6 with the locally relevant category 1 and 2 (rural) stations. (There were not enough category 1 stations to do it with just category 1). The calculation takes into account how far away the “rural” stations are, so that more weight is given to closer stations.

Estimate of actual UHI by referencing the closest rural stationsEstimate of actual UHI by referencing the closest rural stations – again categorized by population density

And the relevant table:

Temperature delta from nearby rural areas vs population density
Temperature delta from nearby rural areas vs population density

Conclusion

Here’s what the author has to say:

On the one hand, it indicates the presence of warming trend over 0.3 °C/decade in Japan, even at non-urban stations. This fact confirms that recent rapid warming at Japanese cities is largely attributable to background temperature rise on the large scale, rather than the development of urban heat islands.

..However, the analysis has also revealed the presence of significant urban anomaly. The anomalous trend for the category 6, with population density over 3000 km−2 or urban surface coverage over 50%, is about 0.1 °C/decade..

..This value may be small in comparison to the background warming trend in the last few decades, but they can have substantial magnitude when compared with the centennial global trend, which is estimated to be 0.74°C/century for 1906–2005 (IPCC, 2007). It therefore requires careful analysis to avoid urban influences in evaluating long-term temperature changes.

So, in this very thorough study, in Japan at least, the temperature rise that has been measured over the last few decades is a solid result. The temperature increase from 1979 – 2006 has been around 0.3°C/decade

However, in the larger cities the actual measurement will be overstated by 25%.

And in a time of lower temperature rise, the UHI may be swamping the real signal.

The degree of urbanization around each site was calculated from grid data of population and land use, because city populations often used as an index of urban size (Oke, 1973; Karl et al., 1988; Fujibe, 1995) might not be representative of the thermal environment of a site located outside the central area of a city.


Case 6: California Counties by population show a distinct UHI signature.

My friend Jim Goodridge, former California State Climatologist identified the statewide UHI signature issues way back in 1996. This graph had a profound effect on me, becuase it was the one that really made an impact on me, switching my views to being skeptical. Yes, I used to be a warmer, but that’s another story.

Goodridge, J.D. (1996) Comments on “Regional Simulations of Greenhouse Warming including Natural Variability” . Bull, Amer. Meteorological Society 77:1588-1599.

Goodrich (1996) showed the importance of urbanization to temperatures in his study of California counties in 1996. He found for counties with a million or more population the warming from 1910 to 1995 was 4F, for counties with 100,000 to 1 million it was 1F and for counties with less than 100,000 there was no change (0.1F).

He’s been quietly toiling away in his retirement on his computer for the last 15 years or so making all sort of data comparisons. One plot which he shared with me in 2003  is a 104 year plot map of California showing station trends after painstakingly hand entering data into an Excel spreadsheet and plotting slopes of the data to produce trend dots.

He used every good continuous piece of data he could get his hands on, no adjusted data like the climate modelers use, only raw from Cooperative Observing Stations, CDF stations, Weather Service Office’s and Municipal stations.

The results are quite interesting. Here it is:

ca_temp_trend_map.gif

I’ll have more interesting revelations from Jim Goodridge soon.


Case 7: NASA JPL’s climatologist says UHI is an issue

This press release from NASA Jet Propulsion Lab says that most of the increase in temperature has to do with ubanization:

[NASA’s JPL Bill] Patzert says global warming due to increasing greenhouse gases is responsible for some of the overall heating observed in Los Angeles and the rest of California. Most of the increase in heat days and length of heat waves, however, is due to a phenomenon called the “urban heat island effect.”

Heat island-induced heat waves are a growing concern for urban and suburban dwellers worldwide. According to the U.S. Environmental Protection Agency, studies around the world have shown that this effect makes urban areas from 2 to 10 degrees Fahrenheit (1 to 6 degrees Celsius) warmer than their surrounding rural areas.

Patzert says this effect is steadily warming Southern California, though more modestly than some larger urban areas around the world. “Dramatic urbanization has resulted in an extreme makeover for Southern California, with more homes, lawns, shopping centers, traffic, freeways and agriculture, all absorbing and retaining solar radiation, making our megalopolis warmer,” Patzert said.


CASE 8: You can see it from space. NASA (not the GISS division) measures it. Here’s a report they presented at the last AGU meeting in December 2009. Gee, that curve below looks like Reno, NV, doesn’t it?

profile illustration showing the heat island effect of an urban area

The urban heat island effect can raise temperatures within cities as much as 5 C higher than the surrounding countryside. New data suggests that the effect is more or less pronounced depending on the type of landscape — forest or desert — the city replaced. Credit: NASA
› Larger image


thermal images of suburban and urban Atlanta

NASA researchers studying urban landscapes have found that the intensity of the “heat island” created by a city depends on the ecosystem it replaced and on the regional climate. Urban areas developed in arid and semi-arid regions show far less heating compared with the surrounding countryside than cities built amid forested and temperate climates.

“The placement and structure of cities — and what was there before — really does matter,” said Marc Imhoff, biologist and remote sensing specialist at NASA’s Goddard Space Flight Center in Greenbelt, Md. “The amount of the heat differential between the city and the surrounding environment depends on how much of the ground is covered by trees and vegetation. Understanding urban heating will be important for building new cities and retrofitting existing ones.”

Goddard researchers including Imhoff, Lahouari Bounoua, Ping Zhang, and Robert Wolfe presented their findings on Dec. 16 in San Francisco at the Fall Meeting of the American Geophysical Union.

Satellite imagery of suburban (top) and urban Atlanta shows the differences in daytime heating, as caused by the urban heat island effect. Credit: NASA Goddard’s Scientific Visualization Studio
› Larger image (suburban)
› Larger image (urban)


Yep, UHI is alive and well. Anybody with an automobile dashboard thermometer who drives a commute from country to city can easily measure UHI, and you don’t have to be a climate scientist to prove it to yourself.

UPDATE: For a primer on how UHI is not dealt with by NOAA and CRU, have a look at this Climate Audit post:

Realclimate and Disinformation on UHI

172 thoughts on “UHI is alive and well

  1. Menne study is More Gooder because I remember they cherry picked 43% of the data while Mr Watts was dithering and had only evaluated 87% of the stations.

    Honestly Menne was a little obvious in trying to prematurely pull the trigger and knock down a study before it was complete. A Pre emptive strike.

  2. Given this data, and given that warming per capita falls off with increasing population density, I think its a fair conclusion that the suburbanization/sprawl trends of the late 20th century are generally to blame.

  3. I wish I could record my car thermometer driving into work / driving home. I live in a rural area outside Denver & work in downtown Denver (Colorado, USA, for non-US readers). I almost always see temps 5-10 deg warmer inside the UHI at the office than at home.

    UHI existence is a complete non-brainer for anyone who has had a chance to observe the transition (especially at night, when mixing is less pronounced) . It’s simple physics – all that concrete, asphalt, bricks, etc absorbs more heat than vegetated rural surfaces & re-radiates it, thus increasing the temperature.

    What an inconvenient fact!

    REPLY: Get one of these, get one of those cheap window mounts for flags that stick above the roof line a foot or so, attach it with a couple of nylon zip ties and drive happy:

    http://weathershop.com/USB2_temp-humidity_logger.htm

    Then download the data, and use the included software to plot it. So easy a caveman could do it. I’ll be happy to feature anyone’s UHI plots here. – Anthony

  4. I’m not even sure what this is controversial. I’ve felt this effect many time while driving at night while exiting big metropolitan centers…. with the window down an inch during october or in march/april….. as soon as the corn stalks start appearing you’ve gotta turn on the heat or roll up the window. It’s one reason so many raccoons are roadkill… they’re attracted to the warm asphalt…. the heat is released slowly over the night but they love it just the same…. and there’s a lot of asphalt in the city.

  5. If UHI is influential, why does land based temperature data show close agreement with Satellite data?

  6. The week after New Year, when Cheyenne was quite cold, I drove the city east-west then north-south, and finally all around the belt loop. Outside the city the temperature ranged from -3 to the east to -4 north, to -6 southwest and -2 to the south. Within the city proper temperatures varied from -1 to +1. No, no UHI here. The effect needs a study involving real measurements and not just a statistical regression of “matched” city pairs, or worse, a regression of two big sets homogenized ahead of time.

  7. re: Case 4 BoM blames the Melbourne record high minimum UHI.

    In an O/T comment on the previous WUWT post along with this story I mentioned another story out of BoM (link below). I dont really know who is who in BoM, CSIRO etc, but would love to know the politics right now.

    Here William Kininmonth (former Deputy Head of the Bureau of Meteorology and head of that body’s Climate Centre) highlights distortion of temp data:

    http://www.quadrant.org.au/blogs/doomed-planet/2010/01/the-ipcc-s-flawed-data

  8. You only have to look at the night sky with a infra red “heat” camera to see the “bubble” of heat radiating from towns in the distance, you cant refute hard evidence like this with stupid statistics or models, I have seen it with my own eyes on a clear night as will have any amercian abrams tank commander driving around in Iraq who uses the technology to see bodies hiding in the dark. Check out some of the abrams infrared night sight tank footage and you can see it yourself!

  9. I thought that at least some datasets were corrected routinely for UHI. Is that the case, and are they still correcting the data? How have they determined the extent to which they should adjust the data? These questions are very important because the problem is such an obvious one. Do people not listen to their local weather girl when she says, “Low of 20 tonight, but OUTLYING areas may get to 15″? This is just common sense to any of us living outside the city.

  10. There are heat bubbles even in rural communities. Best example can be found in the Hinkel et al. study of Barrow, AK. Barrow doubled in size over the satellite era, so I expect its heat bubble grew along with it. Given the GISS method of establishing trends in the Arctic, Barrow may have contributed significantly to the supposed remarkable warming of the Arctic.

  11. It isn’t just bricks and asphalt. Cities are situated differently than rural surroundings — sometimes a bit lower in elevation and along a stream or river. In the plains they have more trees–in forests they have fewer. The buildings provide a different view of the sky — hide it at night, and provide canyons with lots of surface area to absorb sunlight in the day. One important issue is the effect of heat dissipation from HVAC, industry, lighting, and so forth. The heat dissipation alone ought to amount to a watt per square meter, which is the order of the “greenhouse effect.” A lot of this dissipated heat has diffused deeply into the earth under cities. And time dependence is what is most important. It is a complicated matter whatever the pundits may say.

  12. Never worry about desmogblog . . . its a fools paradise front operation for David “Dr. Fruit Fly” Suzuki’s global warming hysteria organization. All fear mongering AGW hysteria hyping crap all the time.

    The dude that runs is a PR flak that makes his living shilling for the local socialist/progressive party.

    Always good for a few laughs round these parts.

  13. Kevin Kilty in your post above, what was the ambient air temp of Cheyenne by some other weather station? Also what time of day did you drive, and what were the winds?

  14. Would it be possible to accurately “correct” surface temperature readings using infra-red satellite pictures? Even if not totally accurate, would it likely be a better technique than the “corrections” that are currently used?

    How accurately can a surface temperature can be determined using such a source? Could such pictures be an even better way to collect surface temperatures than now used?

    Assuming NOAA knows exactly where the climate sites are – which is doubtful – such pictures might be useful as a management tool to detect changes in siting or surroundings causing higher readings.

  15. In the second graph you compare Tokyo with Hachijo Island. A nearby island, called Miyake Island being 180 km from Tokyo, exhibits almost no increase in temp at least for 1940-present, though the year-to-year oscillation pattern is the same as Tokyo.

  16. Your work is excellent. Thank you. No doubt, it was undertaken in the spirit of Orwell who said that in these times rational men have a duty to state the obvious.

    I cannot imagine someone actually denying the urban heat island effect. To prove it to yourself, all you have to do is drive from the city to the suburbs or vice-versa. Maybe people get confused among city, suburb, and exurb. To see the effect, you have to visit the city, that part of the metropolitan area that has all the older brick buildings that are jammed together. Driving from the suburbs, with their spacious lawns, to the exurbs, with their huge lawns and McMansions will not do the trick.

  17. the chinese are getting it:

    1 Feb: China Daily: Equal plan of emissions rights
    By Chen Longxiang
    The most crucial task for China in international climate talks is to seek an equal arrangement of emission rights that could guarantee its development interests and basic human rights, says Ding Zhongli, a renowned geologist and vice-president of the Chinese Academy of Sciences in an interview with China Daily.
    While in allocating emissions rights – or the quota of emissions – for different countries, the reduction proposals of the IPCC (United Nations’ Intergovernmental Panel on Climate Change), the G8 and the OECD (Organization of Economic Cooperation and Development) did not consider that the cumulative emissions per capita of developed countries throughout modern history (from 1900 to 2005) has been 7.54 times that of developing countries.
    They assigned developed countries 2.3-6.7 times the future emissions quota per capita more than developing countries, which would remarkably deprive the development and interests of poor countries…
    In his paper on the major proposals for carbon emissions reduction and some related issues, published on February issue of “Science in China”, Ding analyzed the trap hidden in the dialogue on emissions reduction.
    The “trap” consists of: First, demonstrating the high sensitivity of global temperatures to atmospheric CO2 concentration; second, emphasizing the catastrophic impacts of global warming on the biosphere and on humans; third, making the value judgment that the extent of temperature increases since the Industrial Revolution should be controlled under 2 C within this century; fourth, calculating that the atmospheric CO2 equivalent concentration should not exceed 450 parts per million by volume within the 2 C model; fifth, defining the responsibilities of developing countries in terms of long-term emissions reductions; sixth, fixing the quota of developing countries in long-term emissions reduction.
    The key point here is that once the concentration target of 450 ppmv is established, the permitted emissions from fossil fuel combustion and cement production from 2006 to 2050 are fixed accordingly.
    Even though the ocean and land continue to absorb 45 percent of carbon emissions, the total amount of emissions that people all over the world could discharge is at about 255.11 GtC. In the total amount of emissions, however, after developed countries determine their proportion of how much they should reduce, there is not much vacancy left for developing countries to exercise emissions freedom.
    Developing countries may not be fully aware of the “trap”. …

    http://www.chinadaily.com.cn/cndy/2010-02/01/content_9404623.htm

  18. This is a no-brainer. I live in the country ten miles from a small city of 25,000. It is perceptively warmer most of the time in town than it is out in the country. Even my wife comments on it and she has no interest in climate change at all other than politely listen to me on the rare occasions that I bring it up.

    Siting of the weather stations used for climate change predictions in urban areas and then inadequately compensating for the heat island impact is little more than scientific fraud.

  19. Any change in land usage will alter the temperature profile. So irrigating arid land will increase humidity and prevent low minima moving the average temperature higher. Growing trees may result in daytime transpiration of considerable volumes of water in hundreds of litres a day per tree leading to cooler temperature maxima.

    Shouldn’t planetary energy content be measured rather than transient heat in the atmosphere as it is on its way out to space?

  20. OK …. so urban areas, which are created by people, are getting warmer. If we average the UHI temps with the non-UHI temps we are warmer than if we had no urban areas. We really do have anthropogenic global warming; just not caused by greenhouse gases.

    Bob

  21. Thanks for including my blog post on the UHI in Japan! It’s great to see the work get a wider audience.

    Can I get a “most favored nation status” – a listing on your blogroll?

    REPLY: sure -A

  22. Anthony Watts – It was early evening and CYS, which is about halfway down the longest runway at the municipal airport to the east of the terminal, was reporting -1 as I left my home to start this trek and -3 by the time I returned just over an hour and a half later. I have no measurement of the offset between my thermocouple and the airport station, unfortunately. There is a lot of open runway and taxi-ways at the airport, which the military uses as much as anyone, but it is within the city. As I drove by the west end of the runways (about a mile to the west of CYS) I measured 0. When I got home both CYS and I were reading -3, but I am downwind on this evening from every source of heat.

    Wind was out of the west-southwest and quite light as shown by steam clouds rising from the refinery southeast of town, and the Dyno-Nobel plant southwest of the city. The coldest place (-6), to the southwest is a low area along a local creek, and the warmest boundary region to the south of town is high ground along US 85 known locally as the Denver Hill. Interestingly the warmest region within the city was a low area on the north side of the city where US 85 intersects a drainage known as Dry Creek. It was +1 in here. The coldest place in the city proper was -4 in the southwest part of the city along US 30.

    I can probably find the NWS archive for the evening in question.

    REPLY: No need, just wanted to make sure you weren’t driving in 20mph winds. Mixing near the boundary layer negates the effect. -Anthony

  23. “Urban Heat Island Myth is Dead“.

    They should talk to James Hansen. He knows it’s alive and well. He uses it in his product.

  24. Anthony,

    If you read beyond the headline of the Desmogblog, you would see that “Urban Heat Island Myth is Dead“ was shorthand for the point that the urban heat island effects are not having a significant impact on the global temperature data sets that we are using to look at global warming.

    It was not a claim that urban heat islands do not exist.

    REPLY: Oh I understand, but you don’t get to read my email. Many Huffponians were convinced by the title alone. At least my title is accurate, and that the purpose is to show (for those folks that can’t read past the title) that UHI remains an issue.

    But then again, you gripe about most everything here. So I’m not surprised you’d gripe about this too. Oh, you might want to read this from McIntyre, as your scifi hereos don’t seem to correct for it:

    http://climateaudit.org/2009/01/20/realclimate-and-disinformation-on-uhi/

    – A

  25. I spend a lot of time wandering the northern nevada deserts day and night. Temperatures are always warmer, summer and winter at night in the city than out in the boondocks (even when the boondocks are significantly lower in elevation. Driving at night is always interesting,especially on windless nights. Temperatures vary extensively based on topography (rocky areas are always warmer). On still nights when you drop into low spots, it can get bone chilling, but when you rise in elevation out of the cold sinking air pool, its suddenly warm and pleasant…these transitions are always seemingly instantaneous. Near creaks and rivers, its always very noticeably colder. Topography, and geology have massive impacts. Transition zones between warm and cold are short, and in most cases utterly predictable if you know and watch the land. Mr watts would have a field day doing a night drive in my cruiser with his thermometers. The surface of one small valley can range in temperature by 20 degrees simultaneously, but we are supposed to believe they can calculate temperatures from 1200 miles away from somewhere with an altitude difference of over a mile.

  26. In the CASE 5: Heatzilla stomps Tokyo, the Japan author partly summarizes – ” On the one hand, it indicates the presence of warming trend over 0.3 °C/decade in Japan, even at non-urban stations. This fact confirms that recent rapid warming at Japanese cities is largely attributable to background temperature rise on the large scale, rather than the development of urban heat islands. ”

    This appears to me to be consistent with Anthony’s statement in the CASE 5 – ” And the IPCC (2007) summarized the northern hemisphere land-based temperature measurements from 1979- 2005 as 0.3°C per decade. ”

    So, I haven’t done homework about whether other independent (of IPCC AR4 )papers on northern hemisphere land masses show this consistency with the AR4. Sorry.

    BUT, has anyone here done homework about if the AR4 statement is consistent with other land masses, like it is with Japan?

    John

  27. I’m a first time contributor (FTC), long time reader (LTR).

    The R=0.455 value is not that good of a correlation. Were the temperature stations placed directly in the middle of the city and in which direction did temperature get measured from the city? Was it measured out over the ocean or in towards a desert? What I’m saying is that I highly doubt there is a convenient circular arrangement of stations around the “UHI” of interest to give a symmetrical arrangent of temperatures radiating farther out from the original station(s) within the city. What you could be measuring is the variance between multiple stations because of location such as latitude and altitude (more importantly) rather than the temperatures of what the city raises the avg temperature. This is not to eliminate the UHI effect but to suggest other experimental and procedural (as well as bias) errors are effecting the claim of where all attributable temperature increase comes from. A map of where the stations had their data collected from would be entirely relevant especially along with their altitude.

    Just an extra piece of skeptical reading from me is that the pressure systems could be altered significantly from many events such as the UHI or if there was localized melting of glacial patterns etc. Given this possibility where high or low temperatures may become altered relatively altering the flow from what used to be a high pressure system of air into a cooler one, where the flow of air is coming from each station could describe (depending on the location of the measuring station obviously) either an increase in the UHI temperatures or a decrease. So if you were to take for instance the night data as opposed to the day data you could find if there was a significant change in the mixing from wind factors and judge whether there exists a deviation of the temperatures but you could also check for a history of the high and low pressure systems of the areas and if they are altered in any significant way (per statistical analysis which i know you like to do).

  28. 4 billion (18:52:46) :

    “If UHI is influential, why does land based temperature data show close agreement with Satellite data?”

    With 70% of the earth’s surface covered by water what is the likelihood they would differ beyond the amount they DO differ?

  29. Anthony — When I said no UHI here I was joking. It was pretty obvious on this evening (7 Jan), the entire city except for low areas along US 30 at the city’s west edge, was at least 1F warmer than countryside.

    REPLY: Well if you want to do it for real with a datalogger, let me know and I’ll send you one. Might make an interesting student lab study. – Anthony

  30. I agree with Mervin that R=.455 is pretty sketchy for drawing any substantial conclusions. The plot doesn’t look to be much more than a cloud of points.

    I think the study needs to fine tuned a bit.

  31. Recent California climate variability: spatial and temporal patterns in temperature trends (CLIMATE RESEARCH, February 2007)

    Steve LaDochy, Richard Medina, and William Patzert

    “If we assume that global warming affects all regions of the state, then the small increases seen in rural stations can be an estimate of this general warming pattern over land. Larger increases must then be due to local or regional surface changes. Using climatic division data, the fastest rates of warming were recorded in the southern California divisions, where urbanization has been greatest. The least warming occurred in the Central Valley, with the more irrigated south (San Joaquin drainage) having greater warming than the less irrigated north (Sacramento drainage). The NE Interior Basins division had cooling over the period of record, although most stations in the northern divisions had insignificant rates of change.”

    “The largest temperature increases were seen in the state’s urban areas, led by Southern California and the San Francisco Bay area. . .”

    If the excess warming occured only in urban areas, I think we can conslude that UHI exists.

  32. The temp drops at least 5 degrees between Palmdale/Lancaster, CA and Rosamond…. Every morning on my drive to work

  33. A few years ago I attended a seminar for wx spotters. Those attending were ham radio people. The meteorologist giving part of the presentation said that it was believed that the reason that the city of Chicago had never been struck by a tornado was the city generated so much heat and the heat prevented it.

  34. For Marvin, I’m not much of a statistician I’m afraid. The significance levels are derived from how reliable the fit is – and they are mostly 99%, with a few at 95%.

    There is a lot of data with a lot of scatter – but still a significant trend. Confidence in the trend increases with number of points sampled (which is a lot).

    The high level of scatter is one of the most interesting points about the paper. Looking at just a few stations might easily send you off in the wrong direction. Micro-climate effects are very influential and maybe impossible to predict in advance.

    The other significant point about the paper was the verification of high “real” surface temperature warming over Japan for the period of the study.

    I didn’t understand your question “which direction did temperature get measured from the city?” These are stations measuring the temperature at specific locations throughout Japan. The researcher explored the temperatures recorded to the population density at that point (not in the center of the city).

    http://scienceofdoom.com

    CO2: An insignificant trace gas?

  35. Hey there Joel Shore, I remember you telling me you had nothing to do with Desmogblog when I asked you about the lies they posted about my father. What do you have to say about that now? Your credibility is in question.

  36. You don’t have to be a scientist to notice that it’s hotter in the middle of any town/city with bitumen streets, buildings and no trees, than it is in the surrounding countryside with trees, grass and only the occasional building. They must drive around in air conditioned cars and work in air conditioned offices to make statements such as that. UHI is alive and well !

  37. An article said that in Israel (I think that’s right) home owners are required to white-wash their roofs every year. Seems they realize UHI is very real and move to minimize it.

  38. Good post Anthony, UHI is alive and well at Canberra Airport too – 0.3 degrees C per decade, and has been fed for years into global trends. See my post on 12 Jan 2010

  39. I can say the Japanese study by Fujibe (Case Study) is an utter bogus, because the years since 1979 constitues the very period where dramatical urbanization took place all over Japan.
    Until 1960s where the Olympiad was held in Tokyo (1964), mostl parts of Japan were rural and cars were rarely seen in the countryside. At a number of stations keeping a long observation record, the temperatures exhibit no clear trend whatsoever from the 1880s up to 1960-70s, but show a remarkable rise thereafter, 1 to 2 degC for middle-sized cities and 0.5 to 1 degC even for small cities/towns.

  40. Case 7’s link to the JPL climate site seems to have been removed, or redirected?

    Thanks for the link to the temp/humidity data logger. I’ll be looking into one.

    REPLY: The link was orphaned and then redirected to the main page by NASA’s new climate website for some reason, alternate found, fixed. – Anthony

  41. Sal (20:55:34) : Correct Sal, but more importantly, it is affecting the averaging, especially when certain stations are used (urban) and others tossed out (rural). Their claim of “nothing to see here” is ignorant. I will decide for myself if there is nothing to the effect of UHI. I guess it is hard for me to fathom that there are people out there who would just accept their claim of irrelevance.

  42. http://www.ide.titech.ac.jp/~icuc7/extended…/362428-3-090430175623-002.pdf

    http://ams.confex.com/ams/pdfpapers/144519.pdf

    http://infoscience.epfl.ch/record/100035

    Anthony, Long ago when we were discussing the Parker paper I was begging everyone to take a look at the BUBBLE study. Have a look. a very detailed look at the problem

    lpas.epfl.ch/MOD/publi/rotachetal(05).pdf

    There is also a website somewhere.. arrg

    http://pages.unibas.ch/geo/mcr/Projects/BUBBLE/textpages/ov_frameset.en.htm

  43. If a city has had a stable population, land use extent, and energy use over the years then the fact that it is warmer than rural shouldn’t effect the RATE of increase in temperature.

    The Japanese and California studies, it seems to me, are primarily quantifing the rate of temperature increase due to energy use patterns and to some extent miss the possible effects of growing populations and city extent, which I would think would be more dominant factors. Both large/high density and small/low density city groups would have had some high and low growth sites in the groups. Though one might think that the high density/large city groups had on average more growth over time than smaller cities. This might explain why the graphs had such poor r values. ie. I think the studies are using size/density as a proxie for city extent/population growth rate and they are not especially good proxies.

    I would like to see a study that compared the rate of temperature increase for growing cities, both population and extent versus stable cities versus rural sites.

    I would bet that a much stronger correlation would turn up.

    Or how about a multivarate regression using population, land use extent, automobile usage, and time versus temperature for cities.

  44. Something that bugs me about UHI is that is shows up as increased nightime temps. I see it in a town of 3,500.
    The part that gets me is that the light domes seem to coincide with the heat domes, at rough glance. Any chance some of the UHI is due to light intensity trapping Longwave Radiation?
    A station that is heavily urbanized and has suffered a blackout for the night or two would be a test case.

  45. For me I don’t need a scientist to tell me a city is warmer than rural.I would expect any scientist trying to average temperatures over a long period of time would take into account the UHI effect.
    Marvin
    You have just proven my opinion which is,no scientist should state anything with certainty.
    They should just say,my research shows blah blah blah,but bear in mind that my research is based on factors that I have allowed for,but there could be a heap of factors I didn’t allow for.
    As a member of the unwashed masses,I don’t want to know what some scientists who may have missed a whole heap of factors,tell me what the future is in 50 years.I would rather them be concentrating on real issues,such as figuring out how to predict earthquakes.I would be happy to see real money thrown at that problem,I am not happy to see money thrown at a problem invented by science.
    I accepted what the scientists said about AGW,I had a quiet laugh about the thought of the nations of the world being in complete agreement and saying”better think of our people in 50 years”I knew there would never be universal agreement.
    It didn’t bother me because if it is going to happen, then it will.
    But then I found out just exactly what was being asked of my children,and future generations to try and fix a problem (that may exist)when there was no hope of fixing that problem.
    Why didn’t the IPPC simply say
    We may have a problem.
    We cannot impede progress(that leads to a bigger problem)
    Let’s set up a fund,funding science,not a big amount
    Let’s set up a war chest.
    Let’s invest that money with the world bank(who has control of said money)
    Let’s deal with each problem as they arise.
    let’s use that money to make sure that when corrupt governments accept payment from other countries allowing them to mine their resources,that the mining is done as cleanly as possible.
    There is so much good the UN could do,but it is swamped by the hysteria over AGW.
    Nobody is forcing the UN to do good,the leaders are too busy trying to use AGW as an extra tax grab.
    There is no doubt in my mind that the UN has become corrupt,and is a colossal failure,yet my government wants me to keep on contributing to that failure.

  46. 4 billion (18:52:46) :

    If UHI is influential, why does land based temperature data show close agreement with Satellite data?

    Because the “Team” couldn’t adjust the Satellite data.

  47. Well, Susan Solomon is still a Warmist, though she may be moving gradually towards Luke Warmist:

    “She [Solomon] would not comment on the mistake in the IPCC report — which was published in a separate section on likely impacts — or on calls for Rajendra Pachauri, the IPCC chairman, to step down.”

    Sounds like a loyal true believer, still gargling the Kool-Aid?

    “What I will say, is that this [new study] shows there are climate scientists round the world who are trying very hard to understand and to explain to people openly and honestly what has happened over the last decade.”

    Do, or do not. There is no try.

  48. Doug in Seattle (20:09:16) : :”I agree with Mervin that R=.455 is pretty sketchy for drawing any substantial conclusions. The plot doesn’t look to be much more than a cloud of points…”

    Doug, this is climate science, where a dildoclimatology sample size of a dozen +/- is considered to give significant results, but not to be so significant that they have to include the sample size itself in the article. It’s like ancient astrology–they’re lucky to get the decimal place right. R = 0.455 is fairly strong, considering the field.

  49. Those guys can’t still figure out what a 6th grader can figure out ( http://wattsupwiththat.com/?s=6th+grader )… UHI is real and anyone with the smallest sense of observation can feel it on any sunny day.

    In a way this is good. Before they were ignoring the counter arguments to AGW now we have an apparent discussion/argument going on… still aggressive though but I guess old habits die hard.

  50. I live in Reno and have a cheapo weather station setup in the backyard. The sensor is sited such that it actually gives a good relative reading, and I’ve calibrated it.

    What is so amusing is the evening weather report, where I’m seeing temps on the news that are typically 5-7 degrees warmer than mine for the “current” evening reading at 6-7 pm.

    When I first drove a car with a built in thermometer through Carson City, I noticed a sharp 2-3 degree increase in temp while driving through town, then it went back down. Going both directions, winter and summer, regardless of time of day.

  51. The UHI effect is similar to the photochemical smog effect. The smog happens in densely car populated areas (city downtowns) and almost none existing outside cities. In fact, UHI and photochemical smog are related.

  52. I’m a little confused…

    The end of Jones’ abstract says “Urban-related warming over China is shown to be about 0.1°C decade−1 over the period 1951–2004, with true climatic warming accounting for 0.81°C over this period.”

    So the period was 53 years, which meant the “Urban-related warming” attributed .5C of that .81C or was it in addition to the “true climatic warming making a total of 1.3C for that period?

  53. Apparently it is controversial when the author that no less than “Nature” has annointed as “brilliantly” debunking all those nasty climate denialists says it obviously doesn’t exist and is just part of the conspiracy.

  54. A little OT but I was checking over at RC where they were discussing the Glaciergate when I ran across this comment with Gavin’s reply

    Not only is the IPCC fallible, but NASA is as well, and even more so.

    http://climate.nasa.gov/evidence/

    Had almost the same error, just a little worse.

    “Mountain glaciers and snow cover have declined on average in both hemispheres, and may disappear altogether in certain regions of our planet, such as the Himalayas, by 2030″

    Note the 2030 figure, not the 2035 figure. I assume NASA must have used another source.

    The comment has been silently vanished today, but you can still read it in the Google cache.

    If there are any NASA employees here, can they perhaps comment on why NASA published an incorrect statement, and then silently removed it without any comment on their error – unlike the IPCC.

    Will NASA take some steps to remedy the false information that has been read by many of their web viewers? Perhaps by a statement, or even a link on the offending web page pointing out their previous error?

    [Response: That’s a joke right? They fix an error, and now you want them to track down and apologise to everyone who may have read it? If something is wrong, it gets fixed. You should be happy. – gavin]

    I think Ill submit this to Wiki as a definition of “hubris”

  55. Is DeSmogBlog saying that there is no UHI or that its impact is negligible? Either way I will put my life on the fact that there is a significant temperature difference (3-7C) (or more) especially at night between where I live now, close to the city centre, and used to live 10km away, in suburbia. The airport where the local weather data is gathered is about 2km from my present and definitely part of my local UHI. I can supply relevant details – city, country, population, terrain, if necessary. The climate of the area is Southern Hemisphere coastal temperate. (never seen snow or ice – yet)

  56. Any chance someone could fix the style sheet at Steve McIntyre’s site? The old one printed beautifully but the new wordpress one is hopeless in Firefox and IE8. I’m trying to increase my carbon footprint and prefer to read from dead trees!

  57. UHI is an effect noted since Roman Times and was the reason
    many notables escaped the city during the summer. Mitigating the effect was why Nero was asked to ‘build streets narrow and buildings high’ following the great fire, where he allegedly fiddled whilst Rome burnt.

    Undoubtedly UHI is real and undoubtedly it is understated in the IPCC figures.

    In some cities-particularly cooler Northern latitude ones-it is likely to be a benefit in keeping the local environment warmer than it would otherwise be . In some naturally warmer cities the additional heat created by man may need mitigation.

    However, what I wanted to ask relates to this post;

    “stumpy (18:56:26) :

    You only have to look at the night sky with a infra red “heat” camera to see the “bubble” of heat radiating from towns in the distance, you cant refute hard evidence like this with stupid statistics or models, I have seen it with my own eyes on a clear night as will have any amercian abrams tank commander driving around in Iraq who uses the technology to see bodies hiding in the dark. Check out some of the abrams infrared night sight tank footage and you can see it yourself!”

    It beggars the question as to what effect UHI has at different heights where data may be compiled. For example, in crude terms, buildings leak heat from their roofs, whilst tarmac reflects heat stored from the day at ground level.

    What is the temperature profle of the UHI effect from the tarmac level itself, to the height of the standard measurement for weather stations, a car thermometer (typically higher than from a land station) plus from the height that satellites measure at.

    Most specifically, how far into the atmosphere would those ‘bubbles’ of heat rise before they become absorbed into the surrounding air or will they become ‘trapped?’

    Tonyb

  58. @Bob Buchanan (19:31:20) :

    “OK …. so urban areas, which are created by people, are getting warmer. If we average the UHI temps with the non-UHI temps we are warmer than if we had no urban areas. We really do have anthropogenic global warming; just not caused by greenhouse gases.”

    What percentage of the total of earth’s surface area is inhabited by humans? My understanding is it’s about 3%. In terms of man affecting the other 97%, it’s the tail wagging the dog, in my view. Man is perhaps causing a few 1/100 of a degree warming globally, but no more.
    A better question to ask is what percentage of the total global temperature monitoring stations are located close enough to this 3% area to be affected by man’s activities, i.e. release of heat? (I’m not referring to greenhouse gases here)

  59. “We show examples of the UHIs at London and Vienna, where city center sites are warmer than surrounding rural locations. Both of these UHIs however do not contribute to warming trends over the 20th century because the influences of the cities on surface temperatures have not changed over this time.”

    I don’t have the data but I suspect that if you look at the growth in the number of vehicles and the increase in electricity consumption over the 20th century in London, then all of that heat generated has to go somewhere. The cars will warm the tarmac, especially as they now crawl along and all the growth in electrical appliances will be massive. For example environmentalists moan about the growth of energy wasteful 4x4s in London, so how can he say there is no change over time, surely that statement shoots destroys his credibility.

  60. 4 billion (18:52:46) :
    If UHI is influential, why does land based temperature data show close agreement with Satellite data?

    Because SST record, covering bigger part of the Earth dilutes UHI affected ground thermometers.
    MSU vs CRU global, 1979-2003: CRU rising 36% steeper
    MSU vs CRU land only, 1979-2003: CRU rising 69% steeper

  61. ” 4 billion (18:52:46) :

    If UHI is influential, why does land based temperature data show close agreement with Satellite data?

    It doesn’t, that is why GISS and Had/Cru show much more warming over the past 30 years than does UAH (satellite). GISS and HAd /cru have a warm bias due to increased urbanisation over 30 years pushing up the temps at many of their urban ground based weather stations. UAH does not show this, check recent articles from this site about the divergence of GISS (land) from UAH (satellite).

  62. This is coming from the other end of the scale of academic depth and accuracy, ie a lay observer, but here goes. I’ve noticed on more than one occasion, but particularly in this recent cold spell, that the in-car temperature gauge very often shows an increase of 0.5 degrees (its accuracy limit) when I leave a main road and join a busy motorway (in northern England), suggesting a “strip heating” effect of the motorway traffic.

    I also remember that, in the bad old days of lower quality diesel engines, if travelling on a long, straight stretch of motorway on a warm, still day, you could see a dark column of dirty air directly over, and for the full width of the motorway.

    Just thought I’d mention it.

  63. If it were just that UHI exists, that would not matter. The problem is that UHI has not been consistent and uniform over the period of measurement. So you will frequently find on warmist sites, for instance Tamino, the claim that if you compare the anomalies over short periods from urban and rural sites, there is little difference. This is true over short periods. But if over long periods, the urban sites have become urbanized and gotten warmer, then it imparts an upward bias.

    The problem is not the existence of an urban warm bias.

    The problem is the existence of an increasing urban warm bias through the measurement period.

  64. These guys aren’t a bit smug are they?

    WHO WE ARE:
    “The DeSmogBlog Project began in January 2006 and quickly became the world’s NUMBER ONE SOURCE [emphasis mine] for accurate, fact based information regarding Global Warming misinformation campaigns.”

    “The DeSmogBlog team is led by Jim Hoggan, founder of James Hoggan & Associates, one of Canada’s leading public relations firms. By training a lawyer,[snip]”

    A lawyer! That’s all I needed to know. As soon as I read this after perusing the DeSmogBlog, the phrase “indicting a hamburger” popped into my mind.

    My accelerator pedal is working just fine :-)

  65. The existence of UHIs is obvious even to most alarmists. The battlefield is clearly going to be one of amounts and how these should be calculated.

    It is an inconvenient truth that UHI adjustments are insufficient in almost all official temperature statistics.

    It is a great pity the sceptics don’t have just 10% of the financial resources of the alarmists for climate research, as the science of global warming and its supposed relation to changing atmospheric carbon dioxide levels would now be in complete and undeniable tatters.

  66. I wonder what an analysis of historical temperature change on significant public holidays might yield? For example on Christmas Day in Sydney the city is very quiet. I wonder if this analysis might reveal a statistically significant anomaly between a “busy” city day and a non-busy city day. This anomaly would provide evidence of local activity influencing urban temperature collection and would also provide a guide to how much urban change affects temperatures. Since I’d hazard to guess that Sydney in the ’70s would be close to Sydney at Xmas in 2009.
    For Sydney in general there is a noticeable drop in activity on all public holidays and most of the period between Xmas and New Year.

  67. Anybody who has ever ridden a motorbike reasonably quickly through the city limits at will be well aware of the sudden drop in temperature one experiences one gets as one leaves the urbanised area for the countryside.

  68. @Ray (22:20:46) :

    “Those guys can’t still figure out what a 6th grader can figure out ( http://wattsupwiththat.com/?s=6th+grader )… UHI is real and anyone with the smallest sense of observation can feel it on any sunny day.

    In a way this is good. Before they were ignoring the counter arguments to AGW now we have an apparent discussion/argument going on… still aggressive though but I guess old habits die hard.”

    Yes, this IS good, we are swiftly moving from step 3 to step 4.

    “First they ignore you, then they ridicule you, then they fight you, then you win.”
    – Mahatma Gandhi

    My accelerator pedal is working just fine :-)

  69. Every generation seems to have to learn the same stuff as the previous generation, over and over. When I was in high school in the early fifties in NZ, our Form Four (year ten) science teacher made it very clear that big cities generated their own weather pattern because of the heat trapped by bricks and concrete during the day and given off during the hours of darkness as ambient temps fell. He urged us to watch the native falcons use thermals over our town to soar to great heights, proof of hot air rising from what we now know as UHI effects. He made the prediction that, as urbanisation increased, so would the problem of urban weather. He was promoting the notion, even then, that, if the public were to recieve accurate climate data, it should be measured out in the rural hinterland , and that data from urban areas should only be used for interest.

  70. How anyone can claim with a straight face that the Uraban Heat Island effect is a “myth” is beyond me. It flies in the face of reason and common sense. I mean, who among us hasn’t at some time personally experienced first hand the relative coolness of the countryside compared with the relative warmth of the City on the same night?
    As has been said previously – it really is a no-brainer.

  71. The weather reports we get here in the UK almost always cite temperature predictions for major urban areas – and then remind us that the temperature will be “one or two degrees cooler” (degress C) in rural areas.

    If UHI didn’t exist then why woud they do this and why would it be true?

    And it stands to reason that if a previously rural area becomes urbanised then the temperature record for that area will show a marked increase.

    As most of us AGW sceptics don’t deny that the world has warmed up over the last 150 years or so (and are mostly glad it did!) and yet most of the AGW proponents spend half their time trying to deny the existence of proven, established climate records (such as the MWP, LIA and UHI) it makes me wonder who should be labelled “deniers”.

  72. Even though Jones tries to minimize the UHI effect elsewhere, saying the UHI trends don’t contribute to warming in London,

    They do according to ex mayor Ken Livingstone.

    Plans to tackle the ‘urban heat island’ phenomenon – which sees London’s temperatures soaring compared to neighbouring areas – are explored in the study launched by the Mayor of London today (Tuesday 10th October).

    London can be up to nine degrees Celsius hotter than the green belt around it, particularly at night. Climate change means that temperatures are now reaching levels that could have serious health impacts and this summer was one of the warmest on record.

    http://cgch.lshtm.ac.uk/Protecting%20Londoners%20as%20the%20capital%20warms%20up%20-%20Press%20Release.htm

  73. Explanations of the UHI effect usually center on man made alterations of the surface. But what is the impact of multiple engines producing exhaust gases at 1200degF? And is body heat about to be placed on the proscription list right next to cattle flatus by the AGW fascists?

  74. I think I saw quite a good demo of UHI when travelling just before Christmas. The snow that covered much of the Uk had been lying for almost a week, so the cover was probably quite sensitive to average local temperatures.
    The South Downs and the land to the north were well covered by snow (it looked very pretty). But as we approached the London suburbs the snow cover started to get noticeably thinner. By the time we were in London proper there was virtually no snow at all.

    Of course, the IPCC dismisses UHI for the obvious reason. I believe it relies on a study by Parker based on observations of wind. It seems quite bizarre to rely on such an indirect method when, as Anthony pointed out, it’s very easy to measure UHI directly.

    It seems to me that if there is a large scale wind it would reduce the UHI effect, as it would constantly bring in cooler air from the surrounding region. But simply using the local wind value would not give a reliable check, as Parker may have done. It is well documented that UHI can create weather systems centred on cities. In other words, the measured wind might itself be created by UHI! In this case the circulation pattern created by UHI would simply move the air around the city and would not have a cooling effect.

    Some of you may have watched the BBC Climate Wars series. It is quite ironic that the presenter, who was clearly an AGW believer, gave an excellent demonstration of UHI at Las Vegas. He simply did what Anthony did – and what the IPCC seems incapable of doing – by measuring the temperature at the edge of the city and in its centre. He showed several degrees of warming. Even in a BBC program devoted to discrediting the sceptics (it failed) UHI was alive and well!
    Chris

  75. Driving from a rural peninsular 50 K out of Melbourne after a hot day, once I leave the farm land for the freeway, the UHI effect up and hits you. But then, I drive with an open window and the air conditioner off. Some people rarely experience out side weather effects these days, let alone the real life sounds of nature! How do they know about UHI?
    OT: attended Lord MoncKton’s Lecture in Melbourne tonight. A virtuoso but evidence based performance, lots of jokes mixed in with the math, to an enthuisiastic, thousand strong audience:-)

  76. So now it appears we have Urban Heat Island effect denialists. Are they now going to rewrite all the elementary meteorology textbooks to exclude this concept as well?

  77. Anthony, I think you are wrong in the interpretation of Jones statement about London and Vienna. I think what he means is that London and Vienna have not grown much the last century and have always been heat islands so the amount of heat island effect in the total temperature rise measured hasn’t changed. That would be true if the effect is mainly due to heat of the sun being trapped in bricks and pavement (and not dependant on traffic, airco’s and energy use in general. In China however the cities are growing fast and so there is more growth in the UHI signal itself.

  78. I live in SE Ottawa Canada. It is the largest city in Canada measured by geography. Since we live in a rural part of the city and SE of the official site for the city temperature (the airport) we experience the UHI every day we drive the 24km to and from work. The variation in the temperature from our home to the city centre can vary from as high as 9 degrees C to as little as 1 degree C. This is all measured by our “highly accurate” car themometer. As the residential sprawl nears the airport and beyond the UHI effect will be more pronounced The question I have is: how do you normalize for this effect when the effect varies so dramatically from day to day?

  79. Obviously, anyone knows that there is a substantial UHI effect surrounding major connobations. This is apparent every day when seeing the evenning weather forcast for the local area. I cannot believe that any serious scientist would dispute this. It is clear that there is a significant risk that this well known effect has poluted the global temperature reconstructions.
    It would appear obvious that the ‘global’ temperature record needs to be reworked from scratch using exclusively only such sites where it would be reasonable to use raw data with no adjustments. These sites will probably be rural stations and the ones which have the longest uninterupted record. It may of course be the case that some global warming is truly being caused by man’s use of land but if so, notwithstanding that urban heat effect may be as high as 4-8C given that 4/5ths of the globe is water and that urbanisation of land is probably at most 4-8%, the global effect will not be substantial. The important point is that if rising temperatures are truly a problem then different solutions would be required such as painting all buildings white, painting the roads and tarmac areas white etc.

  80. guidoLaMoto (03:25:14) :

    Explanations of the UHI effect usually center on man made alterations of the surface. But what is the impact of multiple engines producing exhaust gases at 1200degF? And is body heat about to be placed on the proscription list right next to cattle flatus by the AGW fascists?

    Going off at a mild tangent I have wondered something similar about power stations with cooling towers. Is the energy put into the atmosphere by those negligble?

  81. In Japan, the deterioration of the meteorological stations is known, thanks to the examination of Dr. J. Kondo, Prof. Emeritus, Tohoku Univ. Although he has not published this result in peer-reviewed journals, his work is well recognized.

    He has shown that only three stations are good enough (Suttsu in Hokkaido Isl., Miyako in Tohoku area and Murotomisaki in Shikoku Isl.). The other stations have a problem similar to that Anthony has pointed out; that is, changes in their microclimate.

    Unfortunately Dr. Fumiaki Fujibe seems to have neglected this. In fact, the temperature data of Hachijo Isl. cited above shows only little increases recently.

  82. Gerard (04:18:30)
    I think what he means is that London and Vienna have not grown much the last century and have always been heat islands so the amount of heat island effect in the total temperature rise measured hasn’t changed.

    I disagree Gerard. My Parents were born in 1915 in Peckham in South London and my mother spoke of open country and farmland not far away. There was an enormous amount of development in the 30s (which is the same in most towns in the UK), and this farmland disappeared under the suburbs. In recent years there has been the tendency to pave over front gardens, and with the amount of house extensions this has also changed the way the surface heats up. In addition less rain makes it into the ground. And, car ownership has increased dramatically so that with the exception of those roads with off road parking a road can be lined on both sides with parked cars. On a hot day a car’s bare metal can burn. Where does this heat go? I do not have the figures but London has something like 12,000 miles of road and 11,000 miles of cars.

    I grew up in Bournemouth which back then had a population or around 150,000. Development has been continuous so that open areas I played in as a child have nearly all been developed, and that includes my old school’s sports fields. The UK has lost something like 20,000 sports fields. In addition I remember the trees coming out in leaf as much as 2 weeks before surrounding areas back in the 70s.

    I take issue with the idea that London hasn’t grown much and I also think the term ‘Heat Island’ is mistaken. Although it is possible for a person to be stranded on an island if you have no boat or plane, heat is not confined by urbanisation. It goes up and into the atmosphere. It’s what glider pilots look for.

  83. I wondered why night storage heaters had become obsolete and this explains it!
    Heating blocks of concrete with cheap electricity overnight and releasing that stored heat during the day was a figment of my imagination and the warmth I felt was illusory.
    I never wore shoes as a child, they were paper bags, and it wasn’t a house I lived in, it was a cardboard box!
    I will never be able to thank Desmoblog enough for for correcting my failing memory.
    Ain’t science a wonderful thing?

  84. “becuase it was the one” you might want to fix that. It’s so easy to do when you are concentrating on the topic.

  85. “painstakingly hand entering data into an Excel spreadsheet ”

    The best is to enter or import that data into Access. Then you can run all kinds of SQL queries, including doing standard deviations, averages, maximum, minimum, first and last of grouped records. You can even do Cross Tab Queries which is a field value as a column with another field as a row comparing to a third field as the intersect. The resulting recordset can be copied and pasted into Excel for the plots. Doing it this way allows you far more flexibility and speed to the analysis.

  86. Anthony,

    Here is apoint lost in this debate. A small Rural, say even 5,000 or even as low as 1,000, which we have many out in the plains, too is much warmer than out in country where I farm. Many times our local radio staion will be 5 degrees warmer than the out in the country. Small towns and cities are still comprised of buildings, concrete and blactop. So in reality to acount for UHI effect you can not just compare a small town with a large city. You need to compare sites out in the country side with any sized city……..If all, I mean all UHI is accounted for warming in the past century could be close to nothing. Remember, 100 years ago the was not much concrete and blacktop and even the small towns were much less condensed and populated…….Sincerely, John…

  87. They’re lack of understanding is legion, they don’t even understand the difference between microsite issues and UHI.

    One thought I had a while back was that we have one event that might quantify some of the differences between airport sited stations like ASOS and rural stations. Post 911 was probably the only time that there was no air traffic at any of the nations airports. I had started looking for data and a methodology to see if there was a noticeable difference in temperatures but other things got in the way and I dropped it. I’d love to see someone take a look. I would expect the effect to show up in the peak traffic times at a particular airport. Since ASOS records data all through the day you should be able to see a change in the pattern if it exists.

  88. Hey Anthony and co

    a little off topic and please excuse my grammar etc as I’m typing this on my iPhone

    It would appear than NIWA in NZ is now admitting that it has no idea how or why they modified the national temp records…..HA!!

    http://www.scoop.co.nz/stories/SC1002/S00004.htm

    more info at climateconversation or pc.blogspot

    NIWA says they ‘lost’ the computer code??!!!

  89. @ scienceofdoom (20:26:06) :

    Thankyou I wrote this as I just woke up after reading the article because I had to go somewhere. Hence the horribly obscure writing and it didn’t actually make sense, apologies. I actually misread what the table was saying. I thought the D3 value was to do with distance from the site not the population density per square km (yes i did not read the sentence explaining the table either). Clarrification is a beautiful thing! Note to self, do not make silly posts unless I have had coffee and been able to read the post thoroughly.

    Anyhow, also to do with the R=0.455 value it is still a weak value as it implies a low to moderate correlation it doesn’t matter the significance level is 95% and 99%. The way to read it is that they find it significant that its a weak linear correlation.In other words you cannot substantiate a linear relationship as it is influenced by one or all of the following, i.e. measurement problems of temperature, it is not a linear relationship or other variables are left out which would otherwise correct the relationship. In my opinion it is unconvincing data.

  90. I don’t know, but it sure seems like we need a Global Heat Island Tax. People in these metro areas have been getting a free ride for far too long.

    Either that, or –using my favorite Metro area as a great example– good old NYC needs to knock down a lot of concrete and brick and build about 80 new Central Parks.

    I remain convinced that there’s a fungus or litchen out there somewhere that we could spray on everything from buildings, to roads, to trains, planes, and automobiles, that would offset the effect and cool things down too.

    When it comes to UHI, I think the warmists have some great ideas. Though I’m not that fond of their “Solient Green” breakfast-lunch-dinner drink. Or that “Fahrenheit 451″ thing they keep shouting about.

    Only time and temperature will tell… right?

  91. Anthony PS to the above 6:22:03 post,

    I live next to Interstate Hyw. I-90. Every so far are Met stations that read temp and wind speed. It would be interesting to compare these readings to the official high and low temps through-out the grid. Most of these Met Stations placed along the I-90 hwy. system are well away from the hyw. near the out-side of the right-away. There maybe a small heat island effect still but the buffer is large enough from the concrete of the hwy. that it would be quite small. I would venture to guess that these Met stations (placed to monitor weather out in the country side to warn against dangerous road conditions) would show that there is a Heat island effect even in smal towns where the official temps are taken and used for the official record….John.

  92. It seems clear that the Desmog guys don’t know the difference between proper siting of a surface station and UHI. These are different issues. Urban Heat Islands have nothing to do with how far away the nearest building is from the stevenson Screen. As your map of Reno shows, there is a macro effect across a city, as well as a local effect in the immediate vicinity of the surface station.

  93. JonesII (04:50:35) :

    [that wasn’t in bad taste as much as no taste, and no, I’m not fat. ~ ctm
    Is that a confession? ☺, I just wanted to mention the anthropogenic long wave radiation which contributes to the UHI phenomenon.

  94. I have a copy of study, which attributes 25% of warming trend observed in Prague Clementinum Observatory to UHI. This happen despite fact, that the Observatory is in the centre of Prague and the level of urbanization around is not changing. Authors say increased energy consumption and traffic increase the natural trend, especially in the winter period.
    So if the urbanization spreads around the rural station, summer and night temperatures tend to increase, but in such special case winter temperatures are affected more.

  95. Gerard (04:18:30) :

    Anthony, I think you are wrong in the interpretation of Jones statement about London and Vienna. I think what he means is that London and Vienna have not grown much the last century and have always been heat islands so the amount of heat island effect in the total temperature rise measured hasn’t changed.
    ++++

    Interesting point right there. Tho it would depend on thermometer siting as well. Presumably even the metro of London has been growing, even if the core city has been a UHI for over 100 years. My impression is a lot of temp collecting sites were chosen many years ago in part to avoid the well-known and well-understood UHI, and time/growth has overtaken that effort to ameleriorate the impact of the effect. . .and that is where the UHI signal would be strongest. But still, an excellent point when “trend” is the major concern. What’s important is not just what UHI is adding. . . it’s what UHI is adding more than it did 100 years ago or 30 years ago or whatever.

  96. I’ve said it before and I’ll say it again:

    What is the calibration procedure for the temperature sensors?
    Where are the calibration certificates kept and for how long?
    Against what instrument are these sensors calibrated, and how is that instrument calibrated?
    What is the accuracy of the sensors used?
    Are all sensor measurements performed consistently?
    How is demonstrated that there is a consistency of measurement?

    It appears that the actual values measured at the various locations are taken as gospel with no question on the accuracy of the measurement. It may well be true that some (all or none) of them are ‘accurate’, but without some benchmark it’s like trying to demonstrate that a BigMac is better than a Whopper.

    To that end demonstrating that the urban heat island is a myth is not a scientific study but a ‘statistical study’ (there was no mention of ‘calibration’ or ‘calibrate’ in the peer reviewed article) – “how can we demonstrate using statistics that…”. To that end, any peer review of such a study can indeed be quite supportive of any statistical study, as long as standard statistical processes are used. No amount of statistical manipulation can make up for flawed data.

    Regardless, stating that an urban heat island is a myth is like saying that there cannot be any murders because murder is illegal. I’m sure anyone will tell you it is hotter in a city than it is out in the country. While anecdotal, there is most often a common sense reasoning behind all anecdotes.

  97. A few questions and observations:

    1) Is the equipment used designed to be mounted on moving vehicles? I have no specific knowledge to that point, but I’ve only ever seen them used at stationary locations.

    2) Is there some reason to believe that your vehicle is not acting as a heat source?

    3) I couldn’t find any elevation data regarding your transect. Was temperature variation as a function of elevation/topography/geography accounted for?

    4) I’m time contrained so I just eyeballed temperatures for the “rural” portion of the transect. It appears to average out to about 49 degrees. The average of the temperatures you posted for the airport is 49.5 degrees. Has there been a more quantitiave analysis in that regard?

    5) In my Climatology 101 course as an undergraduate, we learned that UHI effects are most pronounced on cloudless evenings during the winter. The argument could be made that the data collected here approach a “worst-case” scenario.

  98. OT, but interesting and rather funny news from Sweden. In Stockholm the temperature has not been above freezing point at any time during the whole month of January and this has not happened since 1829 (Yes 1829) and SMHI (That is NOAA in Sweden) describs this event as a “sensation”.

  99. 4 billion (18:52:46) :

    “If UHI is influential, why does land based temperature data show close agreement with Satellite data?”

    The question isn’t whether or not the earth warmed in the last 30 years. The questions is did it warm in an ‘unprecedented fashion’.

    If we look at the US record, the difference between 1934 and 1998 is 1/10th of a degree. Easily explained away by any number of ‘non greenhouse’ causes…such as UHI, poor station siting etc etc etc.

    If we compare the satellite records to the surface records then the surface records show slightly more warming the the satellite records.
    .17 degrees per decade for satellite compared to .20 degrees per decade for the surface. 3 decades of comparison gives us a 1/10th of a degree difference. The same difference as between the US 1934 temperature and the US 1998 temperature.

    If the warming that occurred in the 1930’s and 1940’s is statistically no different then the 1980’s and 1990’s then there is no reason to be alarmed.

  100. Surely,the siting of the surface station is as important as population densities.
    A thermometer next to an a-c unit etc will read high even if it outside the only house for 50 miles, and no UHI correction ( assuming they are even made) will be performed. The siting survey needs to done for every station in the world for any accuracy to be achieved!

  101. @Gerard (04:18:30) :

    Many things have changed in the last century in all cities, including London and Vienna.

    Before the 1960’s, most houses didn’t have central heating and most fires died in the evening. There was no AC. Many of the streets weren’t paved.

    In Amsterdam, where I live, all the shops used to be closed on Sunday; the effect of that was measurable in the next Monday.

    All of these things have changed over the last 100 years.

    We should not only count the bodies in cities, but also the energy consumption.

  102. Morgan T said (07:24:56) :

    “OT, but interesting and rather funny news from Sweden. In Stockholm the temperature has not been above freezing point at any time during the whole month of January and this has not happened since 1829 (Yes 1829) and SMHI (That is NOAA in Sweden) describs this event as a “sensation”.”

    Can you please cite your source and provide a link as that is completely contrary to the information here on other areas of Sweden-also follow the links. Is this an extreme example of UHI?

    http://www.thelocal.se/24210/20100105/

    tonyb

  103. Phil M (07:19:26) says:

    A few questions and observations:

    1) Is the equipment used designed to be mounted on moving vehicles? I have no specific knowledge to that point, but I’ve only ever seen them used at stationary locations.

    2) Is there some reason to believe that your vehicle is not acting as a heat source?

    I think the dashboard thermometer in my car is designed to be mounted on a vehicle.

    However, with respect to your second point, by god, I think they have discovered that cars react to UHI! Who would have thought that they produce more heat in urban areas than other areas.

    (Of course, it’s possible that the shape of the city on the transects used by people is such that more power is required going in and less is required going out. That too could explain the temperature profile after subtracting out the bias caused by the nearby heat source that is the car’s motor.)

  104. It’s common sense that removing vegetation & replacing it w/concrete, asphalt, etc, raises temps. Vegetation is a finely-tuned “evaporation machine” that maintains itself around ~70F (21C) during the day by opening/closing the leaves’ stomata (they close at night). This has to have a very significant effect over large, vegetated areas — increasing humidity and limiting daytime highs.

    For desert cities, the effect would be less because the existing land was mostly dry stone/sand/rock anyway, tho buildings increase the sun-absorbing surface area of the dry, heat-retaining materials.

  105. Re
    Morgan T (07:24:56) :

    OT, but interesting and rather funny news from Sweden. In Stockholm the temperature has not been above freezing point at any time during the whole month of January and this has not happened since 1829 (Yes 1829) and SMHI (That is NOAA in Sweden) describs this event as a “sensation”.

    But it is only Weather though.
    Sarcasm off.

  106. The effect of the UHI on Trends is also going to be totally dependant on the rate of change of Building and Population Expansion over the years.
    Now that really would be hard to factor in when using a Rural Site that gets gobbled up by expansion to become an Urban one.

  107. Hey Arianna: UHI is real. Even the folks at CRU know it:

    From: “Jenkins, Geoff”
    To: “Phil Jones”
    Subject: London UHI
    Date: Wed, 24 Sep 2008 15:37:34 +0100
    Cc: “Wilby, Robert”

    Hi Phil
    Thanks for the comments on the Briefing report. You say “There is no evidence with London
    of any change in the amount of the UHI over the last 40 years. The UHI is clear, but it’s
    not getting any worse” and sent a paper to show this. By coincidence I also got recently a
    paper from Rob which says “London’s UHI has indeed become more intense since the 1960s esp
    during spring and summer”. Its not something I need to sort out for UKCIP08, but I thought
    you both might like to be aware of each others findings. I didn’t keep a copy of Rob’s PDF
    after I printed it off but I am sure you can swap papers. I don’t need to be copied in to
    any discussion.

    Cheers
    Geoff

  108. Harry (07:35:58) :

    If the warming that occurred in the 1930’s and 1940’s is statistically no different then the 1980’s and 1990’s then there is no reason to be alarmed.
    ++++

    Y’know, I’ve never believed that conclusion to be true, even if the predicate is granted. I’ve always felt that one of the great tragedies of this whole AGW furball was the proponents insisting on the “unprecedented” bit and all that went with that, and the (regrettably necessary, but better to have been avoided in the first place) skeptics righteous resistance of the diddling of the historic record.

    But all of that doesn’t really matter, in the end, to my way of thinking. That the warming *could* be natural doesn’t mean it *is* natural. That the warming *could* be from C02 doesn’t mean it *is* from C02. Arguments over the historic record can’t really prove that one way or the other, and have been a whole a tremendous lot of wasted time better spent on trying to figure out the real basic questions on feedback sensitivities, energy budgets, and basic processes.

    I hold the warmists responsible for this, as they chose that “unprecedented” battleground, and once chosen the rest was inevitable.

  109. The desmogblog article was poorly worded, but let’s not lose sight of the big picture.

    UHI isn’t dead; it never was. There are of course individual stations where you can see a UHI; oftentimes the UHI causes a fairly constant offset so it doesn’t matter to the trend; sometimes (Reno) the trend is affected as well.

    But why highlight Reno, without discussing what adjustments are made at Reno? Reno was in fact highlighted in Menne et al (2009), BAMS 90: 993-1007. See Figure 8. Have a look.

    The desmogblog aside, the real point is whether UHI effects are causing some significant impact in national or global means, after adjustments are made. This has been quantitatively analysed many different ways (comparisons of rural vs urban, rural vs overall, windy vs calm nights, etc), and the answer appears to be no. Highlighting the raw data from individual stations with a spurious warming trend (which matters) or stations with a fairly constant warm offset (which doesn’t matter) doesn’t affect that finding; you have to go a step further to see what difference it makes.

  110. Dr.T G Watkins(Wales) (07:37:32) :

    “Surely,the siting of the surface station is as important as population densities. A thermometer next to an a-c unit etc will read high even if it outside the only house for 50 miles, and no UHI correction ( assuming they are even made) will be performed. The siting survey needs to done for every station in the world for any accuracy to be achieved!”

    Your sentiment is echoed on this website frequently. Would you have less, more, or the same amount of confidence in a thermometer mounted on a moving automobile?

  111. Joel Shore (19:45:26) :
    Anthony,

    “If you read beyond the headline of the Desmogblog, you would see that “Urban Heat Island Myth is Dead“ was shorthand for the point that the urban heat island effects are not having a significant impact on the global temperature data sets that we are using to look at global warming.”

    Joel,

    How could menne’s study which is focused on US stations, and recall that the US is a pitifully small portion of the globe, say anything of note about the situation of UHI in the ROW. Let’s recall that when NASA got the US temps wrong, that people rightly pointed out that the US was a small portion of the globe. WRT Menne’s study Since I know it works from the wrong data set I would not even read it so I can’t see how someone can even claim a myth is busted, when the myth busting paper used the wrong data.

  112. jknapp (21:26:52) :
    “If a city has had a stable population, land use extent, and energy use over the years then the fact that it is warmer than rural shouldn’t effect the RATE of increase in temperature.”

    I would like to see a study done comparing global warming to economies, housing development, urban sprawl, etc.

    I’m certain most, if not all, of global warming can be attributed to that.

  113. Roger (05:59:22) :

    I wondered why night storage heaters had become obsolete and this explains it!
    Heating blocks of concrete with cheap electricity overnight and releasing that stored heat during the day was a figment of my imagination and the warmth I felt was illusory.

    Likewise, in the 60’s and 70’s when the “back to nature” people were actually trying it, various somewhat effective historical heating arrangements were described where heat was captured in the awake time by brick and stone, which would then decrease the in-house temp. drop overnight. However, having failed and with their further seperation from reality, now the people who obsess on and on about “sustainability” only want the Gov’t to wave a magic wand to make it “all better” – whatever “all better” means. These are very troubled people, imo, and are easily recruited by cynical or deluded “leaders”. But instead, each of them need to figure out and look at what is bothering them to begin with, if possible but often not, I’m afraid.

  114. Phil M (08:49:27) said:

    Dr.T G Watkins(Wales) (07:37:32) :

    “Surely,the siting of the surface station is as important as population densities. A thermometer next to an a-c unit etc will read high even if it outside the only house for 50 miles, and no UHI correction ( assuming they are even made) will be performed. The siting survey needs to done for every station in the world for any accuracy to be achieved!”

    Your sentiment is echoed on this website frequently. Would you have less, more, or the same amount of confidence in a thermometer mounted on a moving automobile?

    You are being dishonest again. No one proposes using thermometers mounted on cars for determining the average temperature of the world. However, you can get a clear indication of the extent of the UHI effect using them when driving through a city.

  115. Joel Shore

    I was just lamenting yesterday that I hadn’t seen you or Scott Mandia posting for a long time. Nice to see you back again. However your post wasn’t one of your best-there is no doubt that IPCC and Real Climate- amongst many others- try to downplay the problem.

    Why not try and redeem yourself by answering my question( TonyB (00:22:53) concerning temperature profiles :)

    Tonyb

  116. The car thermometer certianly shows UHI!
    During the recent, nay ongoing!, cold spell here in the UK, when I leave home to drive into the nearest town, some 15 miles away and another 40,000 people, then the thermometer rises by between 1-2 Centigrade. This is usually a trip done in the evening/night, so no rising sun to warm things up and the engine’s up to temperature within a few miles, so no confounding heat sources.
    The comments that London & Vienna stopped “heating” in 1900 are dubious.
    Wouldn,t the passing of clean air legislation and the reduction of smog that produced have any effect on ground temperatures?

  117. Btw, Anthony/Evan–

    Will you guys in your paper be proposing any way to improve the classification system currently in use to be more useful in grouping sites? From what Evan has been hinting at, obviously the “1s” at airports are flawed from what one would expect from a “1”. . .and thus classification improvements would seem to be in order to better group expected accuracy of results.

  118. Stan (03:20:22) :

    “…As most of us AGW sceptics don’t deny that the world has warmed up over the last 150 years or so (and are mostly glad it did!) and yet most of the AGW proponents spend half their time trying to deny the existence of proven, established climate records (such as the MWP, LIA and UHI) it makes me wonder who should be labelled “deniers”.”

    Stan, I learned the hard way that liars, thieves and conman always accuse the person telling the truth of the charges they are guilty of. If you find someone in your group is stealing, he is generally the one who is very quick to point the finger at someone else. I have seen this happen in several cases over my rather long life time. It is one of the reasons I doubted AGW.

  119. Richard Wakefield (06:13:18) :

    “painstakingly hand entering data into an Excel spreadsheet ”

    The best is to enter or import that data into Access.

    AHHhh but was the data on a computer or was it hard copy? Young folks keep forgeting much of the older original raw data is on paper not on computers.

  120. D. Patterson (22:57:25)
    See:

    http://www.cnrm.meteo.fr/gmme/Pages_perso/page_perso_masson_oct2009.html

    Note the photograph (ROFL) and the discussion of Urabn Climate and Climate Change.

    As an avid bicyclist, one issue that immediately caught my eye in the photograph of the bicycle mounted thermometer is its location. It should be placed in front of the bicyclist, not directly behind him. It is well known that there is a vortex of heat and evaporating sweat being drawn off the bicyclist’s body as the bicycle moves forward. That they would place a sensitive thermometer inside that vortex area suggests that the study designers were more concerned with aesthetics than controlling for confounding variables.

  121. Well there’s one aspect of these UHIs that is seldom mentioned. Those tar and concrete structures, that absorb solar radiation readily and rise to hotter temperatures; are also better radiators of LWIR thermal radiation which is a cooling effect.

    I have often observed that a hot tar parking lot quickly cools within just a few minutes after sunset.

    So personally, I don’t see that UHIs are a problem. They heat rapidly to higher temperatures, and then radiate faster to return LWIR to outer space, and then they cool rapidly after sunset.

    The problem in my view, is that the modellers do not account for UHIs the way Gaia does. Gaia properly integrates all the gosintas and the gosoutas, for UHIs and swimming pools, and lawns and shrubbery, and comes up with a correct temperature to set for the average.

    But the modellers seem to think it is ok to use that UHI measured temperature to represent the temperature of some totally different place that may be 1200 km away from the UHI.

    Yes I know they do that for “anomalies”, but if the sampling strategy is inadequate for mapping absolute temperatures; then the baseline mean that anomalies are referred to is prone to errors

    The tropical dry deserts are the ultimate in heat islands; and they also are the most efficient radiators, responsible for the strongest cooling during the noonday high temperatures.

    On a related issue; can anybody point to any data relating to the difference between surface temperatures with high wispy clouds (which some insist are a warming influence), and the same location with the exact same water vapor profile; but lacking only those high wispy clouds.

    In other words; how does one separate the surface warming due to atmospheric water vapor (a well known GHG) and the warming due to just the cloud, that still lets in a lot of sunlight, but somehow blocks a lot of outgoing LWIR.

    There must be screeds of peer reviewed data on that subject, since all the text books claim that high clouds heat the surface, and the higher the clouds, the more they heat the surface. How to you take out the water vapor effect from the cloud effect ?

  122. Was the locating of a temp sensor between two airport runways done deliberately to catch the extra heat from airliners taking off with full jet exhaust blowing horizontally while accelerating along the runway before heading upward? Or was it designed to respond also to the big volume of hot gases emanating right at ground level from the jets when the thrust reversers are blowing full-blast along the runway upon landing? Will we now see an effect of global cooling if the recession causes a reduction in takeoffs and landings?

    REPLY: it was designed to measure the conditions on the runway, not climate. Even NOAA’s own meteorologists admit to this. See this video:

    “ASOS…placed for aviation purposes…not necessarily for climate purposes.”

  123. geo (08:37:30) :

    “…. Arguments over the historic record can’t really prove that one way or the other, and have been a whole a tremendous lot of wasted time better spent on trying to figure out the real basic questions on feedback sensitivities, energy budgets, and basic processes.

    I hold the warmists responsible for this, as they chose that “unprecedented” battleground, and once chosen the rest was inevitable.”

    The “unprecedented” warming was very necessary to stampede the unthinking human herd into agreeing to be fleeced by the World Bank. The leaked draft agreement called the “Danish Text” that had “Developing countries react furiously” shows this was the ultimate goal. http://www.guardian.co.uk/environment/2009/dec/08/copenhagen-climate-summit-disarray-danish-text

    AGW never had anything to do with real science. It was a Con Game from start to finish and only now are the real facts surrounding that Con coming to light.

  124. “AHHhh but was the data on a computer or was it hard copy? Young folks keep forgeting much of the older original raw data is on paper not on computers.”

    That’s what OCR is for. And I’m not young, just 20 years of programming experience.

  125. From George E. Smith 10:22:43:

    The tropical dry deserts are the ultimate in heat islands; and they also are the most efficient radiators, responsible for the strongest cooling during the noonday high temperatures.

    <<<<<<<<<<<<<<<<<<<<<<>>>>>>>>>>>>>>>>

    The imbalance between heat radiation in and out is apparent when walking on the hot sand at noon, especially if barefoot. Of course, re-radiation out to space at night restores any remaining imbalance.

    But the analogy is still questionable because tropical dry deserts remain relatively fixed over a period of several decades, whereas the growth nature of UHIs, that keep spreading outwards over a period of decades, is quite different.

    It is the growth factor of UHIs spreading out into the suburbs that can create the appearance of a rising global temperature over time. I believe this is why satellite temperature measurements, being unaffected by UHIs, show virtually no global warming over 40 years, whereas ground-based measuremants apparently do.

    While population of our large cities is fairly constant, population rise in the surrounding suburbs has been rapid. I have wondered if increases in regional population over time could serve as a proxy for the UHI effect over time. More people means more houses with roofs, furnaces and electric power consumption/dissipation, more driveways, more roads, more schools, more shopping centers, bigger airports, etc., etc.

    Bob

  126. Jim Goodridge’s diagram showing long-term temperature trends in California is a powerful piece of evidence.

    I look forward to his future revelations.

  127. “Assessment of Urban versus Rural in Situ Surface Temperatures in the Contiguous United States: No Difference Found” (2003 – Journal of Climate)
    Thomas C. Peterson, NCDC

    In Part 1(c), Previous Research into UHI, he dismisses dozens of studies showing significant UHI effects because… their data was not first homogenized or adjusted.

    Peer reviewed by Hansen and Jones?

  128. I was unfortunate in having to live in Central London for a couple years and I know the UHI effect is very real there.

    It doesn’t seem to effect the maximum temperature much, rather it’s the warmer nights which are noticeable, particularly in the winter.

    There have been many changes in London over the last 50 years, most of which serve to amplify the UHI. The Clean Air Act and loss of heavy industry around the centre of London have also had a big warming effect.

  129. Lots of interesting discussion on this topic. I have made my point about the UHI effect probably being greater in emerging cities then in existing big cities. Another point are the surroundings. The UHI effect seems bigger – relative to the surroundings – when the surroundings are desert like and without much trees. That is probably because cooling at night will be much greater at these “bald surfaces”. In my country, the Netherlands I can see temperatures dropping at night much further at these open areas then there were there are much trees or of course cities. What is not often or maybe never taken into account is that trees grow and that in some areas of the world surfaces have become more wooded in the last century. To see how even rural areas might change I include this link with pictures of Dolmen in the province of Drenthe with picture of the landscape now and 90 years ago.

    http://www.hunebed.com/index_multimedia.html

    (click on the numbers of the dolmen d1 to d50, it is good fun)

  130. I lived for 28 years in Hong Kong and can testify to the abrupt changes in temperature when moving from urban/semi-urban areas to some of the few rural areas left in that crowded area.
    I lived in a place called Tai Mei Tuk, a rural area (my garden was frequently visited by porcupines and wild pigs) and I worked in a place called Ta Kwu Ling on what was then the Sino-British Border. Today (01/02/2010 at 21:50 UK Time) the minimum temperatures are, according to the HK Observatory, 17.1C and 18.4C. Just a few miles further south in southern Kowloon the present temperature is 19.9C. The maximum temperatures were 19.5C for Tai Mei Tuk, 18.4 for Ta Kwu Ling and southern Kowloon is 20.8C.
    QED

    UHI lives!

  131. If I understand correctly, those who are trying to justify the drastic reduction of the number of monitoring sites, while using those which are more predominantly in or near more developed or urbanized areas (which already have demonstrated disproportionate “warming”), have rationalized that they are only interested in the magnitude of the “anomaly” (delta). This is a fallacy. In the last couple of decades, we have experienced a massive increase in home, automobile and workplace automatic temperature control which automatically puts out much more heat into our environment, whenever our ambient temperature goes above or below “optimum”. Thus, wherever people live, work or play, measured temperature tends to rise!

    We already know that even in the United States, different regions have radically different characteristics:
    A. Population densities (urban as well as rural)
    B. Personal responses to hot and cold weather or climate (e.g. inclination to suffer and sweat or bundle up vs. turn on air conditioning or heat.)
    C. Availability of air conditioning or heat when they want it (or can afford it)
    D. Predominant types of architecture (e.g. High thermal mass structures accumulate heat.)
    E. Geography/Geology

    Internationally, differences in culture, architecture, and stage of economic development have even greater impacts on urban vs. rural heat effect per capita and city sizes. Thus, it appears to me that “Urban Heat Islands” cannot be categorized or factored by population size. We must have the maximum number and diversity of locations of well designed temperature monitoring stations that utilize platinum resistance sensing elements or equivalent, that are insensitive to radiation heating,.and only measure air temperature. Ideally they will be placed in areas well removed from direct effects of human activity. Only then can we begin to know whether there is significant, unnatural “global warming”.

  132. Incidentally in that satellite image of the UK under snow the other week, you can actually see the major cities in a slightly darker grey. Birmingham, Stoke, Manchester, Leeds / Bradford all visible, and I think also Hull and Aberdeen.

  133. What would it take to get Google to put a thermometer on their street-view vans as they drive around? Each measurement would have a time stamp and be geolocated. The UHI would be quite obvious after a short time!

  134. >>I think what he means is that London and Vienna have not
    >>grown much the last century and have always been heat islands

    Firstly, London has grown considerably. The population has increased, from about 5m in 1900 to about 7m in 1990.

    http://data.london.gov.uk/datastore/package/historic-census-population

    Secondly, the density has increased dramatically, as this graphic shows.

    http://spatialanalysis.co.uk/2010/01/12/london-population-density-1801-2001/

    Thirdly, the amount of energy each person used has probably doubled or trebled. The amount of energy we feed into London, be that oil, gas or electricity, must have a bearing on the resultant temperature. (UHI temperature increase is not simply the result of buildings capturing incident light better than fields and being drier).

    .

  135. “”” bob paglee (10:30:51) :

    Was the locating of a temp sensor between two airport runways done deliberately to catch the extra heat from airliners taking off with full jet exhaust blowing horizontally while accelerating along the runway before heading upward? Or was it designed to respond also to the big volume of hot gases emanating right at ground level from the jets when the thrust reversers are blowing full-blast along the runway upon landing? Will we now see an effect of global cooling if the recession causes a reduction in takeoffs and landings? “””

    When I get on a twin engined 757 or the like to fly out of SFO to say Auckland; fully laden with fossil fuel, and luggage and passengers; I care not a jot for Dr James Hansen’s masticated GISStemp ravings. What matters to me is the density altitude of that bleeping runway; So I know; or at least the flight crew knows whether it is quite safe to perform the ONLY optional part of any commercial airline flight; which is commonly referred to as “The Take-off”.

    They can blast all the jet exhaust they like into that runway Owl box, for all I care so, long as the temperature sensor gets it right.

  136. Richard Sharpe (09:05:41) :

    “You are being dishonest again. No one proposes using thermometers mounted on cars for determining the average temperature of the world. However, you can get a clear indication of the extent of the UHI effect using them when driving through a city.”

    Could you point out which sentence was dishonest or misleading? I admit I try to ask thought-provoking questions, but I try very hard to communicate clearly and without guile. I believe you and I have had a similar, more cordial exchange on a different thread. All of the uncertainties I mentioned then still apply here, in my opinion.

  137. Richard Sharpe (08:02:38) :

    “I think the dashboard thermometer in my car is designed to be mounted on a vehicle.

    However, with respect to your second point, by god, I think they have discovered that cars react to UHI! Who would have thought that they produce more heat in urban areas than other areas.

    (Of course, it’s possible that the shape of the city on the transects used by people is such that more power is required going in and less is required going out. That too could explain the temperature profile after subtracting out the bias caused by the nearby heat source that is the car’s motor.)”

    I’m find some of the language you use there a little unclear, so let’s set aside points #1 and #2 for a moment. Perhaps the other uncertainties I raised (#3 and #4) are the more salient questions?

    Or if you find my alternative view point particularly offensive, I would think #5 would set the tone for an interesting, more amicable dialogue.

  138. @Allen (04:36:29) :

    “The question I have is: how do you normalize for this effect when the effect varies so dramatically from day to day?”

    The short answer is you can’t. For UHI corrections, there is simply too much noise in both the UHI values and the values you are attempting to reference to, thus the correction factor is in reality, a wildly swinging random variable.
    One intelligent guess does not equal scientific datum, and two intelligent guesses does not equal scientific data.
    Assumptions and guesses are made everyday by scientists, engineers, and mathematicians. When an otherwise well intentioned scientific project results in failure or a non sequitur occurs, it is almost always caused by (a) faulty assumption(s) or guess(es). However, assumptions and guesses (not to be confused with a hypothesis) are not science and math, at best they are in the realm of art (if skillful), and at worst hacking (i.e. “to damage or injure by crude, harsh, or insensitive treatment; mutilate; mangle”). The field of Medicine is considered an art, thus “The Art of Climatology” has a certain ring to it IMO.

  139. toyotawhizguy (00:09:37) :

    “When an otherwise well intentioned scientific project results in failure or a non sequitur occurs, it is almost always caused by (a) faulty assumption(s) or guess(es).”

    On what are you basing this statement?

  140. This Python quote is for Joel Shore, from the minstral’s song; “when danger reared it’s ugly head, he bravely turned his tail and fled”.

  141. I looked at the report by Menne, but without the raw data, it is not very informative. Is the raw data available somewhere?
    The findings by Menne are so counterintuitive that I am reasonably certain that something is fishy. The idea that UHI is not a factor and that poorly sited stations are just as good as well sited ones is really hard to believe. Asphalt hot, grass cool. Quantum mechanics is counterintuitive, UHI should not be.


  142. George E. Smith (10:22:43) :
    Well there’s one aspect of these UHIs that is seldom mentioned. Those tar and concrete structures, that absorb solar radiation readily and rise to hotter temperatures; are also better radiators of LWIR thermal radiation which is a cooling effect.

    I have often observed that a hot tar parking lot quickly cools within just a few minutes after sunset.

    I’d like to see some experimental/observation data to support that assertion …

    The ONLY area I have seen cool ‘minutes after sunset’ are vegetative areas devoid of the constructs of man …

    (Perhaps your experiences were with thinly laid asphalt, with very little underlayment – not a load-bearing road surface or airport runway/taxiway).
    .
    .


  143. George E. Smith (10:22:43) :

    In other words; how does one separate the surface warming due to atmospheric water vapor (a well known GHG) and the warming due to just the cloud, that still lets in a lot of sunlight, but somehow blocks a lot of outgoing LWIR.

    Observationally it was apparent that thin clouds do little to block LWIR; during tests with the former mother company (TI) aboard their Convair 380 doing FLIR testing/demo-ing it was easy to see and note surface features (roads, traffic, buildings) through light overcast whereas optically (with eyeballs) one could not see those same features – but of course not so with heavier cloud cover … yet another reason A/C are equipped with FLIR (its not just for night vision) in a ‘war zone’.

    Proof: Recall the ‘optical window’ in the 10 um area bordered either side by WV and CO2. This is also roughly the Planck curve spectral peak for 288 K earth.
    .
    .

  144. “”” _Jim (08:08:38) :

    George E. Smith (10:22:43) :
    Well there’s one aspect of these UHIs that is seldom mentioned. Those tar and concrete structures, that absorb solar radiation readily and rise to hotter temperatures; are also better radiators of LWIR thermal radiation which is a cooling effect.

    I have often observed that a hot tar parking lot quickly cools within just a few minutes after sunset.

    I’d like to see some experimental/observation data to support that assertion …

    The ONLY area I have seen cool ‘minutes after sunset’ are vegetative areas devoid of the constructs of man …

    (Perhaps your experiences were with thinly laid asphalt, with very little underlayment – not a load-bearing road surface or airport runway/taxiway). “””

    Well now that you mention it, it actually was a tar (blacktop) road surface, that I noticed cooled rapidly when the sun went down. And as a matter of fact, it actually had cooled before actual sunset, but the sun was blocked from that road surface area by houses and trees.

    Are you suggesting that that the concept of blackbody radiation is wrong, and a higher temperature black surgface will NOT radiate energy at a higher rate than a cool one. Because that was my point; that it is the earth’s hottest surfaces that are responsible for most of the cooling radiation; in fact the hottest surfaces can be radiating at more than ten times the rate of the coldest surfaces; and that could all be happening at the same time; on some northern summer day, while Antarctica is in its winter midnight.

    As to the high thin clouds business; it is asserted by climatologists, that high thin clouds warm the earth by blocking LWIR, so that such clouds are a POSITIVE feedback warming effect. On the other hand low dense clouds are a cooling negative feedback effect, by blocking sunlight from the surface.
    Someone cited a standard climate textbook graph; that I have squirrelled away somewhere, that has plots of earth surface temperature versus cloud cover percentage, as a function of cloud height. And those graphs claim that the higher the clouds, the warmer they heat the surface by blocking LWIR from escape.

    Well you know what they say about scientific experiment; you can’t ever prove anything is true with any finite amount of experimental evidence; but you can prove it false with but a single negative result.

    So we can assert immediately, that those graphs of cloud cover and height, and surface temperature; cannot be correct, since nowhere on those graphs, is there any evidence that the humidity of the intervening atmosphere has any effect on the surface temperature/cloud cover relationship. According to those graphs; you can have zero relative humidity right up to where those high altitude clouds form, and you get exactly the same surface temperature, as you would if the humidity was 99% all the way up to those clouds. Those textbook graphs show no evidence that the amount of water vapor in the atmosphere has any effect on the warming caused by clouds.

    Yet it is claimed that water vapor is a greenhouse gas; in fact the most important one.

    So those climate textbook graphs have to be pure nonsense.

    The Planck curve may place the spectral peak at 10.1 microns for a 288 K radiating surface, but it can be as low as 8.7 microns for a +60 deg C hot desert surface, or as long as 15.9 microns for the ultimate cold of about -90C at Vostok, and such places.

    And lets not forget that ozone dip at around 9-10 microns, in the middle of that atmospheric window.

    Personally, I am of the belief that it is the surface temperatures, and the atmospheric humidity conditions, that are the CAUSE of those high wispy clouds; not the RESULT of those clouds. But the textbooks conveniently leave out the water vapor GH effect, when they credit those high wispy clouds with positive feedback warming of the surface.

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