The Hockey Stick

difference-between-rural-and-urban2

Via WUWT, Jeff Id takes a look at the GHCN temperature data base, specifically comparing warming in urban vs. rural locations.  As found in a number of other studies, about half of 20th century warming int he surface temperature record may be due to uncorrected urban biases.

Some past takes on the same subject:

  • alf

    Is the global temp. that important if the ocean heat content has been increasing?
    http://climateprogress.org/2009/10/10/skeptical-science-global-warming-not-cooling-is-still-happening-ocean-heat-content/
    —or is this another misrepresentation??
    Confused!

  • lws

    I got interested in Urban Heat Island Effects. How big is it and is it compensated for in the surface station record.

    This is not a rigorous Peer reviewed study but it gave me hands on knowledge of the phenomenon.
    I do not expect anyone to believe my analysis over a peer reviewed study, but I know the truth and Professor XYZ cannot fool me.

    My Answers

    1) It is large

    2) It appears not to be compensated for correctly.

    I bought a temperature logging thermometer which takes temperature samples every 1 minute and downloads the data to a PC, which draws a graph.

    I started in Downtown Dallas at sundown on a very hot sunny day. [93 0 F]
    Went to a park by city hall [91 o F]
    Drove at 60 MPH to about 35 Miles North of Dallas. [86 0 C]

    I repeated the exercise on a Sunday early before dawn. [My control experiment]

    1 Degree warmer in Dallas than in the country.

    I think 7 degrees difference is substantial. don’t you.

    I don’t know if you could accurately adjust that much variation out accurately even if you wanted to.
    [More on this point next post]

    That is why Dr Hansen insists on keeping the surface stations mixed in with the satellite readings, because the satellite only indexes show no significant warming in 11 years or more.

    I am a scientist at heart and a skeptic. I never take some one else’s word if I can check it for myself.

  • lws

    Question:How well is the Urban Heat Island Effect compensated for ?

    I went to the GISS website and downloaded the temperature record for two locations I know a little about.

    Here is the link

    http://data.giss.nasa.gov/gistemp/station_data/
    The two data sets I downloaded were
    Hensley Field [ a Naval air station which started in 1923 and is substantially unchanged]

    DFW airport was a cow pasture 1/2 way between Dallas and Ft Worth prior to 1977 when a massive airport was built.

    Since they are about 15 miles apart they should have the same temperature differences.
    No raw data is available but the least “corrected” data had “USHCN corrections” applied.

    DFW airport pattern makes a big “U” with the upturn starting in …..You guessed it 1977.
    Who would think Jets and runways etc would have an effect on temperature ?

    The Hensley fields pattern was an “L”. there was no uptick after 1977.

    The “Fully Adjusted data for both don’t change the pattern at all.

    Conclusion THE ADJUSTMENTS DON’T REMOVE THE PHONY WARMING FROM THE DFW RECORD..

    Since this is the main station for the DFW area the whole area is misrepresented.

    This is in the USA with the most accurate surface station records in the world ?

    What must Asia be like ?

    This is a non peer reviewed study although I have given enough data it can easily be replicated in 20 minutes.

    I hate taking even the skeptics assertions at face value.

  • boballab

    If you want to look at an in depth study of how the computer code that GISS uses works, how they “infill” for missing stations, How GHCN doesn’t use data from inconvient locations there is no better place then here:

    http://chiefio.wordpress.com/gistemp/

    “NOAA / NCDC have Fudged and Corrupted the Input Data Series
    A sidebar on data corruption from thermometer deletions:

    The GHCN input data to GIStemp “has issues” (they -NOAA/NCDC- deleted 90% or so of the thermometers between about 1990 and 2009…) with those deletions focused on cold places. This is the second set of reports most folks ought to read. We explore that here:”
    http://chiefio.wordpress.com/2009/11/03/ghcn-the-global-analysis/

  • ADiff

    Here are a few comments on the subject of Ocean Heat in this context that might be one entre’:

    http://wattsupwiththat.com/2009/05/06/the-global-warming-hypothesis-and-ocean-heat/

    http://wattsupwiththat.com/2009/10/09/ocean-heat-content-dropping/

    Note, Ocean Heat was introduced to excuse the failure of temperature observations to match AGW model predictions. Now, since Ocean Heat data fails to match the predictions required to support its validity to excuse model predictive failures, AGW proponents are resorting to recursive levels of ‘explanations’ (which seem increasingly speculative) to explain failures in the Ocean Heat predictions. Of special interest is the tendency of AGW proponents to blame the results rather than the model. Instead of assuming their models might be flawed, they search for any possible flaws that might be plausible in the results, including some that seem both far-fetched and impossibly nebulous (i.e. ‘If the heat’s missing, it simply MUST be going ‘somewhere’…because we know our model’s right….).

  • hunter

    Your kid can show that land use affects temperatures. He can’t show that this introduces bias into the temperature record. His retarded father doesn’t understand that these things are different, doesn’t understand that urban warming can’t melt mountain glaciers or warm the oceans, is entirely ignorant of the fact that the greatest warming is seen in the least populated places in the world. I fear for the kid. The world would be better if people as stupid as his father weren’t allowed to raise children.

  • Anonymous

    Fear, indeed. The kid will grow up knowing that bad incentives can make people fool themselves and others regardless of whether they are called politicians, scientists or something else. As an added bonus, the kid will learn to tell a legitimate argument from a spit left by a virtiolic troll by a mile.

  • I found it interesting that in the last week with the cold weather throughout the northern hemisphere, the concept of natural variability was discovered. So what is natural variability? It is so simple that even a 68 year old fart with a spreadsheet can do it. I go into details on how to do it on my web site:

    http://www.socratesparadox.com.

    Now that natural variability is out in the open, it is interesting to note that all of the years, from 1880 to 2008 fall within plus or minus 3 standard deviations.

  • Cloneof

    Wait… You have two blogs?

  • ADiff

    Leaving aside the emotional kindergarten vitriol indicative of matters of personal faith rather than objective analysis, one ‘hunter’ says “urban warming can’t melt glaciers or warm oceans”. But it certainly does, at least to the same extent that CO2 can be shown to do these things. Observable ocean warming appears uncorrelated to either phenomenon, to the extent it’s occuring, and glacial melting preceeds both clearly demonstrating it’s been caused by something other than either.

    The same ‘hunter’ says “the greatest warming is seen in the least populated places”, which is patently untrue sui generis, and in those isolated case where it might be arguable, perhaps he’s really looking at cases like this: http://www.climate-skeptic.com/2010/01/station-adjustments.html or perhaps http://www.climate-skeptic.com/2009/12/russians-accuse-cru-of-cherry-picking-station-data.html ?