Urban Heat Islands and Temperature Observations

Discussion in 'Environment' started by Toronado3800, Nov 28, 2009.

  1. Toronado3800
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    Toronado3800 VIP Member

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    Thought about this one the other night driving back from 60 miles outside of St. Louis where it was 4 degrees cooler.

    I think its accepted as fact urban areas are warmer than adjacent "natural" or rural areas. If I understand right this is because:
    1. Concrete structures holds heat.
    2. Human mechanical activity creates heat.

    Why is this never brought up in discussions for or against global warming? It could be considered:
    1. Proof human structures are raising world temperatures.
    2. A reason greenhouse gasses aren't the leading cause.

    I'm wondering what percentage of U.S. and world wide stations are in Urban areas. Any climates where city or developed areas are cooler than the prevailing landscape? Also any other angles I should take into consideration.

    Personally I'm a believer in the effects of greenhouse gasses, but hey, I'll even argue with myself.
     
  2. FactFinder
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    FactFinder VIP Member

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    The AGW priests choose to ignore the urban effect and actively embrace favoring urban areas in their data. Here is an anlysis of how data was used in Australia.

    http://www.warwickhughes.com/blog/?p=317

    Jones et al 1986 methodical insertion of warming bias
     
  3. FactFinder
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  4. Old Rocks
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    Old Rocks Diamond Member

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    Does Urban Heat Island effect exaggerate global warming trends?

    There has been a great deal of controversy about the accuracy of the temperature data, mainly the bias of temperature data due to urban heat island effect. This controversy has lead many to focus on rural temperature stations. In recent weeks, researchers have been visiting these temperature stations. What they noticed was that there are serious problems with the quality of these temperature stations. They noticed that many of these temperature stations were located next to concrete buildings, near hot exhausts of air conditioning units, attached to metal towers and poles, surrounded by driveways and above gravel.

    What the science says...
    While urban areas are undoubtedly warmer than surrounding rural areas, this has had little to no impact on warming trends.


    When compiling temperature records, NASA GISS go to great pains to remove any possible influence from Urban Heat Island Effect. They compare urban long term trends to nearby rural trends. They then adjust the urban trend so it matches the rural trend. The process is described in detail on the NASA website (Hansen 2001).

    They found in most cases, urban warming was small and fell within uncertainty ranges. Surprisingly, 42% of city trends are cooler relative to their country surroundings as weather stations are often sited in cool islands (eg - a park within the city). The point is they're aware of UHI and rigorously adjust for it when analysing temperature records.

    This confirms a peer review study by the NCDC (Peterson 2003) that did statistical analysis of urban and rural temperature anomalies and concluded "Contrary to generally accepted wisdom, no statistically significant impact of urbanization could be found in annual temperatures... Industrial sections of towns may well be significantly warmer than rural sites, but urban meteorological observations are more likely to be made within park cool islands than industrial regions
     
  5. Old Rocks
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    Old Rocks Diamond Member

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    Does Urban Heat Island effect add to the global warming trend?

    Does Urban Heat Island effect add to the global warming trend?
    It's well established that urban areas are warmer than surrounding rural areas. However, does Urban Heat Island (UHI) contribute to the global warming trend? Short answer, no. Two thirds of global temperature data comes from ocean records, free of UHI effect. For land records, urban trends are compared to nearby rural data - anomalous urban trends are homogenized to match rural records (Hansen 2001). However, in most cases, the urban temperature trend is observed to be little different to the rural trend. A new paper Urbanization effects in large-scale temperature records, with an emphasis on China (Jones et al 2008) looks at this in more detail.

    Comparing rural and urban sites in London and Vienna
    The paper begins by looking at 5 sites in and around London. Figure 1 shows absolute temperatures, clearly indicating a UHI influence on the urban sites at London Weather Centre (brown) and St. James Park (dark blue). The coolest record is the rural based Rothamsted (dark green). However, the excess urban warmth has no effect on the temperature trend - all sites show the same overall trend.
     
  6. code1211
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    code1211 Senior Member

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    Right around the most recent turn of the century, Dr. Hansen and crowd made corrections in the record of temperature to account for variations in the data. Result? The data from about 1965 was unchanged. All temperatures before 1965 were reduced and all temperatures after 1965 were increased.

    To re-state: Older temperatures were adjusted cooler while more recent temperatures were adjusted warmer.

    Assuming heat island effects, this would have been exactly reversed. It was not. Even with data scewed by ever widening heat island effects, NASA under the direction of James Hansen, chose to scew the data more dramatically.

    Below is a link to a graph that shows the original data and the revised data. Also below is the verbiage that accompanies the graph.

    Questions on the evolution of the GISS temperature product « Watts Up With That?

    Blink comparator of GISS USA temperature anomaly – h/t to Zapruder

    The last time I checked, the earth does not retroactively change it’s near surface temperature.
    True, all data sets go through some corrections, such as the recent change RSS made to improve the quality of the satellite record which consists of a number of satellite spliced together. However, in the case of the near surface temperature record, we have many long period stations than span the majority of the time period shown above, and they have already been adjusted for TOBS, SHAP, FILNET etc by NOAA prior to being distributed for use by organizations like GISS. These adjustments add mostly a positive bias.

    In the recent data replication fiasco, GISS blames NOAA for providing flawed data rather than their failure to catch the repeated data from September to October. In that case they are correct that the issue arose with NOAA, but in business when you are the supplier of a product, most savvy businessmen take a “the buck stops here” approach when it comes to correcting a product flaw, rather than blaming the supplier. GISS provides a product for public consumption worldwide, so it seems to me that they should pony up to taking responsibility for errors that appear in their own product.

    In the case above, what could be the explanation for the product changing?
     
  7. JenyEliza
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    JenyEliza Princess of Rhetoric

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    Well, no surprise here. Toronado thinks the whole of Australia is a desert! :rolleyes: :lol:

    Dumbass. Educate yourself....only parts of Australia are desert. Hell's bells in the mountains of NSW and VIC they have SNOW SKIING IN THE WINTER. Ski Reports, Snow Cams & Alpine Accommodation Guide - Australia - ski.com.au

    Stupidfuck!
     
  8. Toronado3800
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    Toronado3800 VIP Member

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    I'm impressed with your intelligence. Why next thing I might find out Mt Charleston is right next to Vegas lol.

    *************
    OK, so St. Louis is causing artificially heating in a 100 square mile area in eastern Missouri.

    If you take readings in St. Louis you'll find out its warmer in the past but be unable to determine why unless you compare them to readings taken maybe 20 miles outside of Columbia.

    None the less its warmer in St Louis......

    But if/since folks take temperature readings close to home you have a problem. A disproportionate percentage of weather stations are near urban or at least suburban areas not some spot 40 miles south of Winnemucca.

    I'm doing some more readings. Thanks for the links.
     
  9. CrusaderFrank
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    CrusaderFrank Diamond Member

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    The ManMade Global Warming Jihadists won't be happy until everything north of the Ohio River is back under 20 feet of solid ice
     
  10. Old Rocks
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    Hi, Stupid Bitch. What a nice way you have of addressing your fellow posters.

    No, Australia is not all desert, just mostly desert.

    File:Australia-climate-map MJC01.png - Wikipedia, the free encyclopedia

    By far the largest part of Australia is desert or semi-arid – 40% of the landmass is covered by sand dunes. Only the south-east and south-west corners have a temperate climate and moderately fertile soil. The northern part of the country has a tropical climate: part is tropical rainforests, part grasslands, and part desert.

    Rainfall is highly variable, with frequent droughts lasting several seasons thought to be caused in part by the El Niño-Southern Oscillation. Occasionally a dust storm will blanket a region or even several states and there are reports of the occasional large tornado. Rising levels of salinity and desertification in some areas is ravaging the landscape.

    Australia's tropical/subtropical location and cold waters off the western coast make most of western Australia a hot desert with aridity, a marked feature of the greater part of the continent. These cold waters produce little moisture needed on the mainland. A 2005 study by Australian and American researchers investigated the desertification of the interior, and suggested that one explanation was related to human settlers who arrived about 50,000 years ago. Regular burning by these settlers could have prevented monsoons from reaching interior Australia. The outback takes up 70 percent of the continent.
     
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