Think UHI doesn't affect the climate? Think again.

From AGU: More urban heat; less summer fog, on California coast

june-gloom-seal-beach

“June Gloom” – Seal Beach near Los Angeles, 2013

Larry O’Hanlon writes on the AGU blog Geospace:

The summer fog that shrouds coastal southern California – what locals call the June Gloom – is being driven up into the sky by urban sprawl, according to scientists who have studied 67 years of cloud heights and urban growth in the region. Less fog may, at first, seem like a good thing. But less fog is bad news for native plants in the coastal hills and mountains, which depend on the cool fog as their only source of water during the rainless summer months. So less fog means warmer, drier, less healthy hillsides and potentially more fires.

What Park Williams of Columbia University’s Lamont-Doherty Earth Observatory in New York and his colleagues find is that the urban heat island effect – caused by concrete and asphalt retaining heat during the day and warming up the nights – is pushing up the moist coastal cloud layer. That turns what was once misty fog into a cloud layer that does not touch the ground.

“Los Angeles and San Diego have the strongest trends for rising cloud-bases and urban warming since 1948,” said Williams, regarding the two most heavily urbanized areas of southern California. “The Channel Islands (which are remote and undeveloped) and other locations have less strong trends.” The new findings were accepted for publication in Geophysical Research Letters (GRL), a journal of the American Geophysical Union.

Suspecting that increasing urban warmth might be driving fog and clouds upward, Williams and his colleagues dug into detailed, often hourly, meteorological data from the region’s many airports back to 1948. The data was trimmed to include observation times that all airfields had in common – 7 a.m., 10 a.m., 1 p.m. and 4 p.m. This was necessary because while some airfields – like Los Angeles – have nearly perfect hourly records around the clock, smaller airports which haven’t always operated at night sometimes had only daylight observations.

The researchers also used census-based estimates of household density in  1950  to estimate urban density within a 10-kilometer (6 mile)  radius of the airports. For more recent years, they were able to use more accurate data from the National Land Cover Dataset. Since urban growth in much of southern California didn’t really take off until the latter half of the 20th century, there has been a lot of urbanization over those nearly seven decades.

What they found is that cloud-bottom heights have risen at airports where there was the most urban growth. The pattern is especially clear at  at night and early morning,  when fog is most common.

Full story here: http://blogs.agu.org/geospace/2015/03/05/urban-heat-less-summer-fog-california-coast/

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104 thoughts on “Think UHI doesn't affect the climate? Think again.

    • Wouldn’t the Sequoia be somewhat protected from the UHI affect being that they are 1) not necessarily in the urban areas and 2) located at higher elevations of the mountains surrounding the urban development?

      • Sorry – forgot the /sarc tag!
        Was in a bit of rush to get out the door for a 3.5 mile jog before the sun disappeared here in the Great NorthWet.

    • No Sequoia to speak of in So. Cal., though I know of a beautiful Big Tree that was planted at the former Nike Missile base at Barley Flat. The elevated fogs moisten the chaparral zone in the San Gabriels. The elevated fogs may delay the onset of fire season and increase available fuel when the fire season does come on. Mt Wilson is quite a sight jutting up out of the cloud deck.

      • Off topic, but I have heard that the rate of growth of some of the redwoods (the really old ones) has essentially exploded. CO2 is good stuff

  1. Nothing shocking here, seems like a reasonable piece. The two greatest impacts man has made on climate are through agriculture and cities.
    I suggest we must renounce both!

    • @Robert, Seeing that you are from Ottawa I suggest you start there, as far as I am concerned living and farming outside those two parameters I am Okay for now.

  2. Actually, UHI’s effect on “the climate” is miniscule, even if its local effects may be significant.

    • Bruce, you are only half right; UHI has a large distorting effect on measuring climate. You could say the cAGW scary narrative is all about how climate is measured (and money and control and politics etc.)..

      • Indeed, the affect of UHI is not miniscule when .10 degrees represents ten years of warming. When the number of stations is reduced almost 90%, and the remaining stations measurements are often not used, but the UHI stations are used, and that warmth is spread 1200 K, then the affect of UHI is greatly amplified.
        How much. I suggest this is a likely reason for the divergence of GISS from RSS, currently diverging at 1.2 degrees per century, and this is also the likely reason both satellite data sets show 2014 nowhere near as warm as 1998.

  3. Robert of Ottawa – Agree with Agriculture and Cities but add forestry and water basin management – either damming or removing water. Big effects. But “local” not global. Look at satellite photos of BC, northern Alberta, Ontario and Quebec forest changes. Now, some is additive and some is negative (CO2 absorption and biodiversity increased in logged of areas; higher reflectivity in logged areas versus unlogged in boreal forests, different in the tropics – many, many variables). Check out some of the big dams and resulting lake effects – James Bay, Williston Lake, Arrow Lakes, Kimano, Mica, Libby Dam, Grand Coulee Dam, Hoover Dam, Three Gorges … Huge local effects. (Not against hydro, just recognizing there are effects.)
    Look at a satellite photo of the urban lighting of the earth at night. There has to be some small effect. Small compared to the sun, but nevertheless, an effect.

    • Wayne, I don’t think Robert of Ottawa was referring to just his locale. Urban growth IS global, not local, when you look at it from that prospective. As for whether its total effect has global impact, well, if you are averaging the data across all land, you are affecting the global readings.
      And urban growth greatly effects the local weather beyond just the urban sprawl itself. Storms that would have moved in a straight line curve around the city, unable to penetrate the neat and humidity bubble, and when they move on, don’t necessarily drop their moisture – or malevolence- on the area beyond. Climate IS local, after all – wherever you are, there is climate, and when you “average” impact over a wider range, urban islands do very much affect the real as well as the relative.

    • The problem is where measurements are taken. Many rural thermometers were taken off the list, so the remainder are more heavily skewed to urban sites–and, of course, urban areas are growing, so that formerly rural sites near cities are now within the urban sprawl. Thus the averages are going to be more and more affected by sites dominated by UHI. Comparisons of rural sites with urban ones still show little or no warming in the former, but detectable warming in the latter. Thus, that 1% of land area accounts for a far larger proportion of the measurements and can skew results, such as giving rise to pronouncements of “unprecedented” warming.

  4. I went for a 2 hour fatbike ride today in Ottawa…it was sunny but -15C. The snow on the trail (rural) was perfect — something you would expect to see mid-winter. On my way back home I noticed that 1/2 the snow on the roads (urban) I’d ridden over 2 hours earlier had already melted.

        • Kevin Lohse

          At -15, would salt make much difference?

          The grit always helps traction. And, the temperature doesn’t stay at -15 forever. Some salt remains to help in later, during warmer days and nights.

      • No. It was dirty snow so I am sure the sunlight wasn’t being reflected like it was on the trail. But the pavement clearly makes a difference. But I am also seeing major melting of the very white snow on my lawns and the low temperature hasn’t exceeded -15C for 50 days. The snow on the trail is still piling up and it will last well into April. So in the space of 2 kilometers you can see winter conditions versus spring conditions thanks to a suburban heat island.

  5. JPP– The factors that contribute to UHI also operate in any inhabited area, and the world’s thermometers are located these inhabited area and/or airports, neither of which are representative of the vast expanse of the earth’s surface.

  6. Was trying to find the date of April 3rd in the 1980s where I worked about 20 miles north of Philadelphia, PA. It snowed about 3-4 inches, but for 3 days it was below freezing and there were roads closed because of major drifting. I remember the robins and other birds were assembled on the cleared roads as they didn’t like standing in the snow…This may happen this year – or maybe not – who knows…

  7. Who wrote this?

    The effect of urban heating on estimates of global average land surface temperature is studied by applying an urban-rural classification based on MODIS satellite data to the Berkeley Earth temperature dataset compilation of 36,869 sites from 15 different publicly available sources
    We observe the opposite of an urban heating effect over the period 1950 to 2010, with a slope of -0.10 ± 0.24°C/100yr (2σ error) in the Berkeley Earth global land temperature average. The confidence interval is consistent with a zero urban heating effect, and at most a small urban heating effect (less than 0.14°C/100yr, with 95% confidence) on the scale of the observed warming (1.9 ± 0.1°C/100 yr since 1950 in the land average from Figure 5A).
    http://scitechnol.com/2327-4581/2327-4581-1-104.pdf

    Here is a paper saying we should see more fog in San Francisco due to CAGW.
    http://adsabs.harvard.edu/abs/2009AGUFMGC33A0720G
    Here is a paper saying we should see less fog in San Francisco due to CAGW.
    http://dx.doi.org/10.1073/pnas.0915062107
    I bid you all a good night.

  8. Since the remote and undeveloped Channel Islands also have the same trend for rising cloud-bases, just not as strong, UHI apparently just contributes to the naturally occurring rise in cloud-bases.

    • Which reminds me of the teleconnection to Mars. Has there been a pause in the Martian polar ice cap melt? I just want to be sure I understand all the amazing powers AG CO2.

  9. Off topic but have a look at the new National Geographic, the headline ” War on science” of course moonlanding denial, vaccines and “climate change isnt true” lead the war on science. Nearly laughed out loud while standing at the checkout.

    • I used to LOVE National Geographic as a kid. That was back when people kept issues and considered them a real treasure. For example, we had the issue that covered the 1964 Great Alaskan Earthquake. I read that copy a million times.
      I haven’t looked at National Geographic for eons. But about a week or so ago a local engineer(!) shoved that article on the ‘war on science’ in my face, making out like I was one of ‘them’. I was so incredibly disheartened when I read the article. It is so pathetic at so many levels that the mind boggles.
      My respect for the magazine (and the engineer) has evaporated completely.
      It was a genuinely sad experience.

      • No question, science is under attack.
        But it’s under attack from some climate scientists, environmentalists and governments.
        It’s the sceptics who are fighting to defend the integrity of science.
        Chris

      • I also have experienced the same thing.
        Environmentalism has been hi-jacked by the Greenies; Science has been hi-jacked by the Grant-Seekers; and National Geographic has deteriorated to a rag. TV’s Nat Geo is just as bad. IMO

    • So you adjusted LA down .4 degrees for a century of warming due to UHI. How do you know that was not a large under adjustment?
      In talking about Peterson 2003 Steve McIntyre stated…
      In this data set that supposedly shows the following:
      “Contrary to generally accepted wisdom, no statistically significant impact of urbanization could be found in annual temperatures.” actual cities have a very substantial trend of over 2 deg C per century relative to the rural network – and this assumes that there are no problems with rural network – something that is obviously not true since there are undoubtedly microsite and other problems.
      Still well above your .4 adjustment to LA is this study done in South Korea.https://notalotofpeopleknowthat.wordpress.com/2015/02/14/uhi-in-south-korea-ignored-by-giss
      “the amount caused by urban warming is approximately 0.77 °C.
      GISS adjustments however were essentially zero. ” A crude average of the above adjustments is –0.05C, so, in net terms, no allowance has been made at all for UHI.”
      Surface T has risen much faster the radioscond… https://stevengoddard.files.wordpress.com/2014/12/screenhunter_5107-dec-10-21-45.gif
      Roy Spencer published this chart… https://stevengoddard.files.wordpress.com/2015/02/screenhunter_7153-feb-14-23-46.gif?w=640
      So when a significant under adjustment is done to an urban area, and that area is used to fill in rural areas up to 1200 K away, the downward adjustment is actually an upward adjustment to the record.
      rural urban UHI adjustment. rural not used urban spread final urban number
      5 7 -.4 6.6

      • formatting messed up at the end, so let me try this….
        rural measured is 5, Urban measured is 7 UHI adjustment is ,4 changing Urban to 6.6. Rural station is not used. Urban station of 6.6 is in-filled to the rural RAISING the rural 5 degree actual 1.4 degrees to 6.6. The downward UHI adjustment raised the actual measurement 1/4 degrees.

    • Since you endlessly repeat that “adjustments have no effect” and “best actually cools”, we are still left with why adjust? You have no independent way of verifying 99% of the adjustments, except of course expectations, so the data should be left untouched with realistic error bars. Automated processes will never be accurate, at any rate since the data and situations are too diverse. It depends on assuming the past data is both accurate and not-accurate. That some changes cannot be real, but everything else is largely correct. It is recognizing the uncertainty in the accuracy of past data, but assuming that you can fix it, without any kind of accurate accounting to see if changes are accurate. The data sucks, we all know that. But changing unknown accuracy data, into adjusted data simply multiplies the uncertainty not reduces it. Unless you have an “accurate” data source to compare against, your simply muddying the waters. Made 100 fold worse by pretending you are reducing uncertainties. Your not reducing any uncertainties, you are adding in new ones. And no amount of soapboxing is fooling anyone into thinking that adjusting a data set of unknown accuracy, is making it more accurate. The scientific method understands how to deal with uncertain data and this is not it. Needs to be said, over and over. Science needs a grounded and verifiable reason to adjust actual data, you can’t estimate an error and correct it, because your still estimating the error. Getting too wrapped up in what we “can” do instead of realistically asking if we should. You cannot introduce accuracy that is not in the data, unless you can adjust to secondary verified source. You can reduce noise, but not uncertainty without an outside source.

      • Brandon C,

        You have no independent way of verifying 99% of the adjustments, except of course expectations, so the data should be left untouched with realistic error bars.

        Lacking an independent method of verifying most of the adjustments, what makes you think that the calculated error would be any more “realistic”?

      • You inform your realistic error bars based on all of the possible instances of possible error identified. You can never do any better than that without an independent point of verification. Identifying a point of possible error does not give scientific accuracy or justification to “fix” the error, unless you have a more accurate independent data set you can cross reference your adjustments to. Identifying a error in recorded data only gives you justification to help inform the error range the data should be subjected to. You cannot, for example, identify a possible error like TOBS and then make an adjustment when you have no way of even identifying exactly when and how bad the error was. You can only identify its possible maximum effect. It is, to be kind, an estimate of the possible effect TOBS might have had and correcting for it, with no independent data to compare to and no way to know if your adjustments corrected an error that you don’t have an accurate accounting of to start with. When did science start working along the lines of “we have to be seen doing something” and left behind accurate accounting of uncertainties?

      • Brandon C,

        You inform your realistic error bars based on all of the possible instances of possible error identified.

        Limited, of course, by one’s ability to think of all possible instances of error. You’re still left with the problem of quantifying those errors after they’ve been identified. At some point along the way, somebody is going to have to start making assumptions, and they’re all but guaranteed to screw up something when they do. That can’t be avoided.

        You can never do any better than that without an independent point of verification.

        Who says that your independent point of verification is any more reliable than what you’re comparing to? It’s a rhetorical question … this kind of stuff is being done:
        http://www2.meteo.uni-bonn.de/mitarbeiter/venema/themes/homogenisation/HOME/C3_Terragona_screen_intercomparison_large.JPG
        Controlled empirical experimentation always warms the soul, dunnit? Description of what’s going on in the photo here: http://variable-variability.blogspot.ch/2015/02/temperature-trend-bias-radiation-errors-screen.design.html

        Identifying a point of possible error does not give scientific accuracy or justification to “fix” the error, unless you have a more accurate independent data set you can cross reference your adjustments to.

        Circular again: how do you know what’s “more accurate”? Further note: we can’t go back and time and install modern instrumentation, “properly” sited and better-screened.

        Identifying a error in recorded data only gives you justification to help inform the error range the data should be subjected to.

        Again:
        1) How do you know there’s an error to begin with?
        2) If you can estimate the range of the error, why can you not estimate what a more correct value would be?

        You cannot, for example, identify a possible error like TOBS and then make an adjustment when you have no way of even identifying exactly when and how bad the error was.

        It’s my understanding that TOBS adjustments are done explicitly from station metadata. I don’t know if that’s true in all cases, if Zeke or Mosh are still following maybe they can jump in and answer. In the cases of TOBS being done from metadata, we do know when.

        You can only identify its possible maximum effect.

        Again your conclusion doesn’t follow from your premises of what is known or knowable. How can you claim to know the maximum error with confidence, but say that a corrected value cannot be determined with any confidence at all?

        When did science start working along the lines of “we have to be seen doing something” and left behind accurate accounting of uncertainties?

        To my knowledge on this topic, never: I see accountings of uncertainties all over the place. [1] Whether they’re “accurate” or not I cannot say — if I magically knew what the real value should be, the conversation about measurement error, estimate error and uncertainties in all the above would be moot.
        ——————
        [1] Here’s one place to look: http://www.cru.uea.ac.uk/cru/data/temperature/#faq8
        How accurate are the hemispheric and global averages?
        Uncertainty estimates are supplied with the same data given at the Met Office site: CRUTEM4, CRUTEM3, HadCRUT4, HadCRUT3.

        GISS: http://data.giss.nasa.gov/gistemp/ which refers to Hansen, et al. (2010), describing all sorts of how they address these issues: http://pubs.giss.nasa.gov/abs/ha00510u.html
        BEST: Rhode, Muller, et al. (2013): http://static.berkeleyearth.org/papers/Methods-GIGS-1-103.pdf

      • Most of your post kind of backs up my point, that the “best” we can do is identify a source of error, use experimentation and/or statistical calculation to “estimate” the “maximum” effect and use that to inform the error bars. That is not to say that this is 100% accurate, hence the “best we can do” and why scientists normally fill their papers with words of caution and caveats.
        I have no problem with BEST or GISS doing the scientific/intellectual exercise of calculating possible adjustments and presenting it as a “possible” historical record. But these are being presented as a corrected, more accurate, historical data to use for experimentation by other scientists. That is not proper science. The fact that many groups like GISS are adjusting their historical data monthly now, means that no paper that used last years GISS historical data is even comparable to one using this years GISS. When you look at the adjustment made to individual stations, it means, if we buy into the idea this data is corrected and more accurate, that any paper that used that raw data is completely wrong now. Even papers using data a few years old could now be significantly wrong. Should we throw out all old papers that use GISS data?
        Of course in reality, using data that has been adjusted so significantly without a more accurate independent data source (yes we all know the uncertainty there, you don’t need to point it out, you only increase data uncertainty with that line of reasoning), increases uncertainties as they multiply through the processes.
        Global average temp is a meaningless statistic, that cannot be measured or experinced, only calculated. And as Mosher points out, the adjustments have a small effect on that scale. But on the micro scale, the adjustments are huge. I don’t care what BEST does to global averages, it absolutely rewrites station data on the individual scale. How do we deal with the fact that their adjustments create a dichotomy, two completely at odds versions of the weather at a single station? Many of these stations have reams of other observational data to support extreme variations and shifts in local weather. I have experienced huge step changes in local weather during my lifetime, that were 100% real. Yes climate is relatively stable on the macro scale, but there is huge variation (and step variations) on the micro scale. Can we accurately adjust weather with automated processes that look for step changes and identifies them as errors? Yes it might work on a macro scale, but not on a micro scale.

      • Brandon C,

        That is not to say that this is 100% accurate, hence the “best we can do” and why scientists normally fill their papers with words of caution and caveats.

        I consider it a minor victory that we’ve come to agreement on that much.

        I have no problem with BEST or GISS doing the scientific/intellectual exercise of calculating possible adjustments and presenting it as a “possible” historical record. But these are being presented as a corrected, more accurate, historical data to use for experimentation by other scientists. That is not proper science.

        Perhaps not in your mind, but it is common practice. Why I am ok with it is because the methods are described, source codes for doing the adjustments are published and available for all to download, inspect, compile and execute. Plus the original data are retained for comparison. I call that transparency.

        The fact that many groups like GISS are adjusting their historical data monthly now, means that no paper that used last years GISS historical data is even comparable to one using this years GISS.

        My view is that’s the problem that science is supposed to have: not being static or otherwise set in stone. No reason to do science in the first place if we’ve all decided what the truth is supposed to be.

        When you look at the adjustment made to individual stations, it means, if we buy into the idea this data is corrected and more accurate, that any paper that used that raw data is completely wrong now.

        Both data sets are wrong and always will be no matter what anyone does or does not do.

        Even papers using data a few years old could now be significantly wrong. Should we throw out all old papers that use GISS data?

        How should I know? I’d think it depends on the subject of the paper and the magnitude of the putative error(s). Do you think that arguing in hypotheticals is “scientific”? I call it rhetoric myself.

        Global average temp is a meaningless statistic, that cannot be measured or experienced, only calculated.

        Generally, global average temperature is not calculated. Here’s about as good a primer on why as I can think of: http://data.giss.nasa.gov/gistemp/abs_temp.html

        And as Mosher points out, the adjustments have a small effect on that scale.

        Perpetually prompting the “gotcha” question: then why adjust?

        But on the micro scale, the adjustments are huge.

        Ok. How do you define “huge”? How many stations have had “huge” adjustments? Is there any level of “non-huge” adjustment that you would be ok with?

        I don’t care what BEST does to global averages, it absolutely rewrites station data on the individual scale. How do we deal with the fact that their adjustments create a dichotomy, two completely at odds versions of the weather at a single station?

        If the nature of your research is to study temperature trends at a specific local, both data sets are available. The people doing it very probably know more issues than either of us have begun to scratch the surface of. As for myself, it’s trivial to write a database query and at least identify and rank stations by before/after difference.

        Can we accurately adjust weather with automated processes that look for step changes and identifies them as errors?

        I do think THAT is a fundamentally good question. Since you allege, but don’t specify, the reams of other data confirming your observation … why not put together a demonstration of some place familiar to you that the adjusted local data arguably diverges from reality because some homogenization algorithm muffed it. I think that would be an extremely interesting analysis, and quite scientifically useful, especially if it is novel.

        Yes it might work on a macro scale, but not on a micro scale.

        I’m pretty sure that serious researchers using these products know better than both of us which to use, when, if not both at the same time for many of the reasons you’ve pointed out. I’ve no way of knowing, of course, all climatologists really could be idiots and/or liars.

      • Since commenting is not common pastime for me, I have never learned the very visually appealing quote boxes you use, so bear with me.
        “Both data sets are wrong and always will be no matter what anyone does or does not do.”
        – Nice to see we can agree on that, now if only you could agree that unverifiable adjustments do not increase accuracy, they simple supply the existing uncertainties with possible added in adjustment uncertainties. This would not be an issue if the various groups didn’t present the adjusted data as proof of various narratives. How many times we do need to be subjected to the “it’s worse than we thought” PR campaign that accompanies a new revision of past data before real scientists call them on the BS? It’s no worse than they thought because they have not reduced the uncertainties on tiny bit, they have only presented a new version of the same data with no more realistic certainty than before.
        “Do you think that arguing in hypotheticals is “scientific”?”
        – yes and so do you apparently. Since what we are really talking about it taking known problematic data and adding in adjustments that are really just assuming that “hypothetically” if this error has this much effect, it would hypothetically change the temps this much. All of this is hypothetical until you can produce hard science experimentation to verify. I’m sure you already know this and Are just being facetious for your own amusement.
        “Generally, global average temperature is not calculated. Here’s about as good a primer on why as I can think of: http://data.giss.nasa.gov/gistemp/abs_temp.html
        – do we need to go through the pretending that anomalies are not based on calculating global temps? Basing your output on a “base period”, does not change that you need to do overall calculations. Stop being obtuse.
        “Perpetually prompting the “gotcha” question: then why adjust?”
        – if you present that excuse as to why people should not object to the adjustments, how is it not a valid question?
        “How do you define “huge”? How many stations have had “huge” adjustments? Is there any level of “non-huge” adjustment that you would be ok with?”
        – I would define huge as the output is no longer identifiable as the original data. This is not about how many stations or how much, it is about proper data practices. I have already said I think the data should be left untouched and using the various adjustment practices to better inform error bars. Perhaps you forgot I already expressed my opinion on that.
        “Since you allege, but don’t specify, the reams of other data confirming your observation … why not put together a demonstration of some place familiar to you that the adjusted local data arguably diverges from reality because some homogenization algorithm muffed it.”
        – Again the “since you haven’t written a paper, I can’t acknowledge your point”. I am not getting paid to do this and I have enough paid work and bills that do not have the time…. OR… the “pay me to do it and I will response”. These are tired excuses on both sides, you have no problem postulating from your point of view, and others will do the same, deal with it. Although even the time I have spent on this comment thread is already reaching critical, so not entirely false. If I had unlimited time I would indulge my curiosity and do just that, so I also agree with your point. Perhaps the lottery will come through this week. But the question of step changes and automation still stand. Step changes are not uncommon on a local scale even with no station changes.
        “I’m pretty sure that serious researchers using these products know better than both of us which to use, when, if not both at the same time for many of the reasons you’ve pointed out.”
        – since serious researchers have arrived at different answers on many of these historical data adjustments, I am not convinced to follow blindly, even if you are. I have already said I have no issue with creating temp series like BEST and GISS, I just take issue with presenting them as “improved data” for research. They are a research product, not a data source. Although I agree that any researcher worth their grant would use the raw data instead of the “value added”. But on the other hand, honestly how many papers do just that? I have read a lot of climate papers over the years and that is rare in my experience. I also find it questionable how many local effect papers use regional or even hemisphere data for temp/effect correlation, instead of local data. It isn’t universal, so spare me the few links showing where a paper did it right.
        But since all temp series start on a local level for adjusting, they all basically agree that it is a micro level issue. It is a progression from micro to macro: start with station data, then regional, then hemispherical, then global. It may not change much on a global scale, but global scale changes are also lost in the noise of local variation. You would not change a global average by -4 degrees, but not think twice about adjusting a local station that much, but adjust a local station too much and a warming trend becomes cooling, a cooling becomes warming. Changes like that need verification to be considered anything other than speculation.
        Again, this is not a problem until the output of your research is presented as more accurate “data” to use for research. It is not data, it is unverified research. Not an issue if it presented to researchers and the public with honest accountings of the realities. But how many “worse than we thought” press releases actually do that? How many temp series actually admit that the adjustments do not increase accuracy and instead can often increase it? This is like kicking a dead horse because it has been happening for so long and is so prevalent, it has become the new norm. But I still remember my university stat classes and we have not progressed to a new level of enlightenment that allows us to move on from the rules. It is worth noting that not a single statistician that I know has any confidence in current climate science, but belief amongst social science majors if near 100%. Odd for a largely statistical based branch of science. Yes this is again my own personal experience that I have not wrote a paper on, so now produce a statistician that believes, and we can both move on happy with out lives.
        P.S. I am sure I missed a few points, sorry but doing to many things at once right now to continue for tonight. I understand that what either of us says isn’t important to each other or the greater issue at large. We are simply enjoying the ability to “buy an argument …..and nothing else”. Although comment boards are closer to “abuse the next door down”. Hope enough people get the reference for a laugh, and we all stop taking it quite so seriously.
        Cheers

        [The mods recommend using the html codes “blockquote” (before the quoted text) and “/blockquote” after the quoted text. Use the angle brackets rather than the ” “quotation marks of course. Italics are “I” and “/I”, bold is “B” and “/B” .mod]

      • The mods recommend using the html codes

        Seeing If I got this right, thanks for the help mods.
        [Yes, that sentence is properly blockquoted. A word apparently not accepted by the spellchecker either. .mod]

  10. Well I’ll be, Imagine that. On the great coast of Maine sailors all know that the fog often clears on the lee side of islands….er…. Island Heat Island? If you put your yacht on a trailer and tow a couple of miles inland there is no fog either. Go figure!!!? I wonder if the presence of a sailboat favoring the lee side of an island heat island can be blamed for anything. I need some guilt! Thank God i can still shiver with climate guilt while I eat my vegetables. Imagine all the critters the garden must have displaced over the years. Not to mention the number of wood chucks that fell to a small lead pellet traveling at high velocity. oh I am so tired of this excrement. Do I need to indicate sarcasm?

  11. Heat is produced whenever electricity is generated and used, irrespective of where it comes from. The use of computers generates heat, lights generate heat, electric motors generate heat, etc., etc., etc.. Heat is also generated by humans as they refrigerate, cook and then metabolism food and drink, with the result that air conditioners are deployed to cool building interiors by exhausting hot air into the atmosphere. Another feature of cities is the ubiquity of cars and trucks with engines that generate heat. Cities have at least one airport and the constant procession of planes coming and going also generates heat from engines, particularly on take-off.
    Since cities are characterized by high population densities, high electricity usage, a multitude of vehicles and busy air traffic, the urban heat island effect should come as no surprise, though attributing the cause to just sun-soaked concrete and asphalt might be a bit simplistic. Where is Paul R. Ehrlich when you need him?

    • “Where is Paul Ehrlich when you need him?
      Probably lost in a 420 haze like most of his Liberal ilk.

  12. So, let’s see see, humans can’t affect the climate with their CO2. But apparently they can with their cities?

    • The number of cities over 1,000,000 has gone from 1 about 200 years ago to over 500 today. What percentage change is that? Not only are night time temperatures higher in cities but so are day time and I can attest to not only the presence of the heat given of by man made structures but also the strength of that heat. I think UHI as a term confines the attention to urban areas, but extra heat is given off by farmland also when the ground is exposed to the sun and it has good drainage.
      I do not think man made structures are bad but it would be foolish to ignore this effect simply because it gets in the way of the more simplistic AGW theme, which appears to be tied to addressing a future greivance. ‘UHI’ even in it’s limited form of Urbanization, doesn’t allow that because urbanization and agriculture are core to all peoples so there is no clear ‘culprit’.

      • OK Stephen, say that you took the temperature of those 500 cities for the 200 years that you mention, AND only those temperatures were used to determine the global temperature. UHI would result in a huge increase in global temperatures. That is what the skeptics are concerned about. The Alarmists downplay UHI even it affects the temperature record, and shows global warming when there is none [or very little].

  13. I was born in Upland, CA. As a kid and young man, I remember fogs so dense in May-June that it was a treacherous drive over to Pomona or wherever in the early AM (my grandfather once totaled a car on his way to work – and he was no speed demon). However, I have lived off and on in the Bay Area for about the last 40 years (still own property there). The fog there comes in about 500 feet off the ground, borne on chilling, clear 50-degree air, and mainly remains up there. I have a couple of incredible photos of the fog swirling around the Bank of America building’s top extremities, taken one day I was walking around in SF.

    • “The fog there comes in about 500 feet off the ground, borne on chilling, clear 50-degree air..”
      It must not have been one of those “heat trapping, positive feed back” low hanging clouds.

  14. Well of course.
    Cities change the weather around them, then city dwellers insist climate change is real.
    And build the city bigger.
    Self reinforcing delusion?
    I have noticed that persons who live and work in the outdoors do not generally fall for the unprecedented nonsense.
    Only a person raised in an enclosed city scurrying from air-conditioned/central heated home to shopping mall and office could imagine mans mighty hand tipping the climate into ???
    Extreme weather???
    Um is that a storm, a incoming weather system or what?
    Funny how being outside at the mercy of the weather seems to remind one just how insignificant we be.
    Humility is not an emotion these “progressive busybodies ” seem comfortable with.

    • “……..fall for the unprecedented nonsense.”
      I don’t know about out west, but here in Ohio this winter has been like the ones I grew up with in the 50’s and 60’s and I bet next winter will be about the same. Time to break down and buy a snow blower this spring.

    • Right. Unless you’re a earth-size giant, nothing/nobody experiences “global” climate. Global climate/weather is just a mathematical construct of local effects.

  15. Wow! “cloud-bottom heights have risen at airports”. What a marvelous boon to us air travelers! Fewer fog/low cloud delays. Count me in favor!

  16. Man made warming at and around AIRPORTS and where are the modern recordings of temperature officially collected ? AIRPORTS Em……….. Wonder why the Official record points to continued warming as AIRPORTS and their surrounds are being covered over with buildings and pavement? pg

    • At a large airport, I think the concrete wins that one. It’s a tossup in large city centers and (sub)urban sprawl where exhaust particulates may or may not come into play depending on whether prevailing winds favor the formation of inversion layers.
      In the grand scheme of things, combustion heat itself is a rounding error. The planet absorbs in one hour about as much solar energy as human activities consume in an entire year.

      • And the effect of prevailing winds winding around the buildings, reducing air flow and cooling.

      • Yes. And at both the airport and inner city, pavement also has the effect of carrying away precipitation, leaving relatively less moisture to soak into the soils as in agricultural areas. Thus, paved areas get far less evaporative cooling.

  17. Southern California coast has never had much fog. Occasionally in winter it has true ground-level fog, visibility less than 100 feet, not really in summer.
    I’m old enough to recall a few facts. “Sexy” bathing suits were a hit in SoCal before anywhere else. Catalina started making bathing suits in LA in the 1920s, as did Cole of California. You don’t wear bathing suits in cold foggy conditions. This is why LA beaches have people sunbathing and dipping, while SF beaches have people in long pants and sweaters strolling in June.
    Surfing was transplanted to Cali before WWII. In the 50’s surfing took off from Malibu to San Diego. Hobie Alter built his first surfboard in 1950. “Gidget, the Little Girl with Ideas” was written in 1957. The thing is you can’t surf in fog. You need to spot waves 200-400 meters out to position yourself, turn shoreward and paddle. In fog, you’re engulfed in foam before you can even turn around.
    In 1961-63, I flew 3 times in early June from LA to Monterey with a stop in Santa Barbara. Once we flew above the clouds, twice under. I don’t know what the ceiling was, but it was high enough to fly with good visibility to the ground, 500 ft? 1000 ft? 1500 ft? I dunno but we weren’t skirting the white caps.
    LA beaches had late-night/early morning stratus cover in the early 60s, which is to say, up at about 1000-4000 ft in the San Gabriels, there was true fog, but below, it was called overcast. Spending a few summers in Salinas, the sky was overcast, with sunlight breaking in the afternoon some days other days not, 8 miles from the Pacific, in June and July. Some light true misty light fog was to be had in Carmel, although 10 miles inland, in the village Carmel Valley, starry nights, very late at night and morning some overcast and sunny warm afternoons prevailed in June . LA beaches in June in the 50’s and 60’s had overnight overcast, stratus, not ground fog at the beaches and some miles inland, coming in from the sea after sunset, clearing in late morning to around noon in most mid-Junes.
    The Southern California Bight slows and swirls the Japan Current inshore, near the SoCal coast. The inshore underwater landscape is generally shallow, so sunlight heats it up. In mid-June beaches from Redondo southward to San diego had water temps 59-64 most years in the 50’s and 60’s. Winds flowed onshore as air heatd and rose inland starting in mid morning and going until near sunset, as hot air rose in the desert and sucked ocean air in. Warm water caused fog to evaporate. By the wee house of the morning, the winds blew offshore. This was dry air. So at the coast, this dry warm air absorbed water droplets and vaporized them at lower elevations. This is why coastal SoCal in June didn’t have the true fog of Northern/Central Coastal California in June.
    BTW, I spent a week in Redwood Country last August from Humboldt County to southern Mendocino. There was fog in the morning, and sometimes all day. The redwoods were spectacularly healthy. In 2011, I drove through the Santa Cruz Mountains. The redwoods were thick.
    Dr. A. Park Williams, BS UC Irvine; MS,PhD UC Santa Barbara, appears to be a young formerly mediocre student, who is demonstrating that yes, there is room for third-rate “climate experts” on the federal-government-funded climate-fear-mongering gravy train.
    California is undergoing a drought right now.But you should have seen the falls in Yosemite in summer ’11. They were fantastic. A water system that was designed to meet the needs of 25 million people and expand agriculture to the West Valley (a pretty much desert, but green able with water), is insufficient with 40 million people, and luddites convincing judges that reservoir-stored water must be free-flowing through the Golden Gate instead of being diverted to feed people, to save delta smelt, and no more dams can be built, because they are “unnatural”. For 1/10th the cost, the environmentalists could support building a delta smelt hatchery and transplant program. It worked for rainbow trout, in California, and as far east as Missouri, which didn’t have rainbow trout before hatcheries.

    • The term “fog” here is being used to depict what we coastal Californios typically call fog. Namely, coastal stratus. Not Tule / inland fog. That is for hoedads.

      • And the Japanese Current comes nowhere near California. You may be confusing it with The California Current which comes down here from the southern Gulf of Alaska.

      • James, Old Fart may be just using an antiquated name for the current because “Japan” and “California” are both names of sections of the same Pacific gyre. So in that sense the Japan current does finally reach the California coast under the name California current. The nit you are picking is sort of like saying the Gulf stream doesn’t get near Africa. An interesting question would be what has the precipitation been in the Coast Range north of Monterey on the Ocean side. When I lived there it was something like sixty inches a year due to fog, rain, and overcast. You know Mark Twain’s: “coldest winter I ever spent was summer in San Francisco”

  18. Anyone got access to the original paper? Speaking as a VFR pilot I’ve got to say the measured cloud base height leaves a lot to be desired. Nowadays its measured automatically with a fixed vertical radar. I’m not sure how it was measured before that, it may have been a combination of pilot reports and visual estimates. You can also estimate the base height from the dew point spread in some conditions. I’m curious if the paper crosses any methodology changes.

    • They used projected light to do it. That was probably more accurate than radar methods.

  19. Despite what even simple school kids’ experiments clearly show, CRU’s Dr Jones claims UHI doesn’t exist: “Jones et al. (1990) and Easterling et al. (1997) that urban effects on 20th century globally and hemispherically averaged land air temperature time-series do not exceed about 0.05°C over the period 1900 to 1990 “

  20. Not buying it. Apparently nobody understands the difference between weather and climate, unless of course we are going to continue to partition climate areas down to 100×100 meter blocks. UHI certainly impacts local weather, but we are a long way of knowing whether it impacts the regional climate, partly because there is no consistent standard for what constitutes a “climate”. We don’t have near enough data to determine whether a few decades of changing UHI can change a climate, which has an unknown variable cyclicity measured in what – decades, centuries, aeons? You can make a case for UHI altering micro-climates, but we are a very long way from determining whether UHI affects continental climate zones.

  21. When a survey asks the question, ‘are man’s actions affecting the climate?’, the answer, as this post shows, is yes. Just don’t go conflating that to mean CO₂ is to blame and we’re all going to hell in an hand cart.

  22. This is from the pretty obvious dept; Microclimates are everywhere, but their effect on climate is nil. So many surface stations measuring microclimate by those who should and do know better and then claim to be measuring climate. My home affects the microclimate of my property where I can grow some plant materials on different sides of the house depending on specific conditions. Place the wrong plant or shrub in the wrong spot and it won’t do well or survive, but placed exactly in the right spot it may live long and prosper.

  23. Perhaps someone has already raised it above but just in case I will ask anyway: has anyone bothered to reconstruct a land-based temperature time series corrected for the UHI effect? Historical data on population growth (if that is an appropriate proxy) must be readily available for most (all?) urban temp recording sites… Would be very interesting to see what the UHI effect-adjusted trends look like. Apology if im way behind the 8 ball and Willis or someone else has covered this already.

  24. So finally, real evidence of man-made climate change! Really important study so thanks for highlighting Anthony. Whats the bet the cagw cultists and their co-conspirators in the MSM report the findings as evidence of man-made climate change – without explaining the absence of a greenhouse gas link…?

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