Note: See update below, new graph added.
There’s a new paper out by Dr. Edward Long that does some interesting comparisons to NCDC’s raw data (prior to adjustments) that compares rural and urban station data, both raw and adjusted in the CONUS.
The paper is titled Contiguous U.S. Temperature Trends Using NCDC Raw and Adjusted Data for One-Per-State Rural and Urban Station Sets. In it, Dr. Edward Long states:
“The problem would seem to be the methodologies engendered in treatment for a mix of urban and rural locations; that the ‘adjustment’ protocol appears to accent to a warming effect rather than eliminate it. This, if correct, leaves serious doubt for whether the rate of increase in temperature found from the adjusted data is due to natural warming trends or warming because of another reason, such as erroneous consideration of the effects of urban warming.”
Here is the comparison of raw rural and urban data:
And here is the comparison of adjusted rural and urban data:
Note that even adjusted urban data has as much as a 0.2 offset from adjusted rural data.
Dr. Long suggests that NCDC’s adjustments eradicated the difference between rural and urban environments, thus hiding urban heating. The consequence:
“…is a five-fold increase in the rural temperature rate of increase and a slight decrease in the rate of increase of the urban temperature.”
The analysis concludes that NCDC “…has taken liberty to alter the actual rural measured values”.
Thus the adjusted rural values are a systematic increase from the raw values, more and more back into time and a decrease for the more current years. At the same time the urban temperatures were little, or not, adjusted from their raw values. The results is an implication of warming that has not occurred in nature, but indeed has occurred in urban surroundings as people gathered more into cities and cities grew in size and became more industrial in nature. So, in recognizing this aspect, one has to say there has been warming due to man, but it is an urban warming. The temperatures due to nature itself, at least within the Contiguous U. S., have increased at a non-significant rate and do not appear to have any correspondence to the presence or lack of presence of carbon dioxide.
The paper’s summary reads:
Both raw and adjusted data from the NCDC has been examined for a selected Contiguous U. S. set of rural and urban stations, 48 each or one per State. The raw data provides 0.13 and 0.79 oC/century temperature increase for the rural and urban environments. The adjusted data provides 0.64 and 0.77 oC/century respectively. The rates for the raw data appear to correspond to the historical change of rural and urban U. S. populations and indicate warming is due to urban warming. Comparison of the adjusted data for the rural set to that of the raw data shows a systematic treatment that causes the rural adjusted set’s temperature rate of increase to be 5-fold more than that of the raw data. The adjusted urban data set’s and raw urban data set’s rates of temperature increase are the same. This suggests the consequence of the NCDC’s protocol for adjusting the data is to cause historical data to take on the time-line characteristics of urban data. The consequence intended or not, is to report a false rate of temperature increase for the Contiguous U. S.
The full paper may be found here: Contiguous U.S. Temperature Trends Using NCDC Raw and Adjusted Data for One-Per-State Rural and Urban Station Sets (PDF) and is freely available for viewing and distribution.
Dr. Long also recently wrote a column for The American Thinker titled: A Pending American Temperaturegate
As he points out in that column, Joe D’Aleo and I raised similar concerns in: Surface Temperature Records: Policy Driven Deception? (PDF)
UPDATE: A reader asked why divergence started in 1960. Urban growth could be one factor, but given that the paper is about NCDC adjustments, this graph from NOAA is likely germane:
http://www.ncdc.noaa.gov/img/climate/research/ushcn/ts.ushcn_anom25_diffs_urb-raw_pg.gif
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Steve Goddard (04:46:49) :
If you read the paper, you can see that station selection of the rural sites was from an evenly spaced grid.
NCDC and USHCN have always made access to the raw data as minimally transparent as possible.
>>>>
This statement is not true. There’s a station list of all 48 rural and 48 urban temperature sites used for the analysis and it’s clearly one from each state instead of one from each grid. By that method, there’s 10 stations in one single grid in New England, and the large western states are under represented.
There IS a map showing station densities of NCDC in the grid, but that’s part of NCDC’s methodology – not of Long’s.
Steveta_uk (00:38:35) :
I also noticed if you turn the graph upside down it appears to be leveling. This might explain the divergence in the Southern Hemisphere.
It may be already written previously,
but may we say?
NCDC-Gate?
Just as we thought: raw rural data shows no increase since 1940. Urban shows a one degree rise, presumably due to heat island effects, siting issues etc.
Key question: what percentage of the earth is urban right now? Shouldn’t the warming formula on land be:
x*urban warming + (1-x)*rural warming where x is the % of urban land mass.
Am I being naif here??
MB (06:58:14) :
The raw rural data shows no drift in temperature over the whole period. Sure, you can put a line through all of those points and it will have a slight positive gradient, but that depends on where you put the endpoints of the line.
The data has an undulation, the amplitude and duration of that undulation is perhaps an interesting feature in that data. But to measure a “linear drift” in the temperature you will need to measure for several cycles of the undulation. I.e. the dataset needs to be at least 3 to 4 times as long before you can start talking about a trend – especially one as small as 0.13C/century.
I any case, what is all the fuss about? I mean, are you kidding? 0.13C/Century. Is that a joke? Am I supposed to be worried about 0.13C/Century? When I look at the temperature record, that is not significant.
>>>>>
It is said that the US isn’t experiencing much warming, but the rest of the world is. Not that you should believe them on that claim. The 0.13 C trend in the US isn’t the thrust of the paper since it cannot be applied globally, but it is interesting in seeing how UHI is being handled.
Also the only reason for removing UHI is to eliminate human land use and heat pollution effects so scientists can blame carbon dioxide as the cause. If we’re just talking about how humans can change the climate then UHI should not be eliminated as it captures the effects of human infrastructure. The scientists will have to model the temperature gradients surrounding a city and really know what UHI is all about instead of their current feigned ignorance.
John Hooper (01:15:12) :
Sounds very convincing, but what about Roy Spencer’s recent satellite analysis?
http://wattsupwiththat.com/2010/02/20/spencer-developing-a-new-satellite-based-surface-temperature-set/
Kind of nullifies everything doesn’t it?
Lastly satellites are making daily life unbearable for all “settled” De la belle epoque scientists. There are only three solutions left:
One: To destroy all those inconvenient satellites at once.
Two: To surrender to facts.
Three:To keep on repeating the mantra how “surprising and unexplainable” is reality for their “flintstones’ universe” model.
@bushy (02:47:50) :
re. Hee HAw, Catlin expedition 2010 soon underway.
——————
I told it already to my father,
“Daddy, food supply on it’s way.”
Best Regards
Ice Bear Junior
Ah! Ha! Mann made warming found! and it’s worse then we thought. CO2 has been found NOT to be the cause! Only computers could be the cause of this warming, as nothing else could be the cause of this. The warming follows the progression and density of computer use. ;?)
Interesting that the upslope of the urban wrt the rural stations starts around 1965, rather than post-war. Studying potential explanations for that might prove interesting.
Jason Lewis (06:05:32) :
Yes it has been done & reported before on here.
I fail to see why this is more revealing than this graph, known for years, and obviously ludicrous when the only adjustment should be down to compensate for UHI.
http://i42.tinypic.com/2luqma8.jpg
Exactly why the raw data is not used. There is absolutely no significant temperature change over the indicated period. All within the norm.
Richard Lawson (00:46:42) :
Not so much a smoking gun but an exhaust trail left by an ICBM!
***********************************************
Yes, that would be the International Climate Bullcrap Machine.
I suppose it is way late to make mention of this but Robinson @ur momisugly 2:03:16 links to a part of the Arctic shelf broke off which is a report about Antarctica. I don’t see that anyone corrected this – most readers here will mentally substitute one for the other as the size, shape, and context indicate. But words matter and when the wrong one is used it frequently molders, muddles, muddies, scrambles, confounds, or confuses the meaning.
It seems Dr. Spencer used more and different “thermometers” but similar methodologies. So it should not be surprising that his results are similar to CRU’s.
“Similar to the Jones methodology, I then averaged all station month anomalies in 5 deg. grid squares, and then area-weighted those grids having good data over the Northern Hemisphere. I also recomputed the Jones NH anomalies for the same base period for a more apples-to-apples comparison.”
…
“Of course, an increasing urban heat island effect could still be contaminating both datasets, resulting in a spurious warming trend. Also, when I include years before 1986 in the analysis, the warming trends might start to diverge.”
Re: John Hooper,
Spencer’s analysis is from 1989-present.
The divergence between rural and urban in the graph here starts around 1965 (well, the 11-year average does), and it already quite substantial by 1989. Eye-balling the chart above, it looks like rural and urban change by about the same amount from 1989-present, too.
So Spencer’s analysis doesn’t “nullify” much of anything. It may “nullify” 1989-present, but so does that above chart.
Spencer’s analysis could be used to claim that the drop-off in station numbers around 1990 has no substantial difference, but this analysis suggests a strong warming bias was introduced to the surface record in the 60s in the urban stations and that adjusting rural stations by this benchmark further skews the issue.
All urban weather stations (i.e. towns with pop > 15,000) should be removed from the raw average temperature data sets. Remember, these are local weather stations, that were never intended to be used for estimating world climate. By employing stations located in “hot spots”, we are not measuring climate change at all. Future climate monitoring should be based on satelite measurements of atmospheric heat levels directly – after all, we actually want to know: “is it getting hotter!
Steveta_uk (00:38:35) :
The primary fact to remember is that “global warming” is a social phenomenon…
Interesting point. The real point of recognizing UHI is the fact that even though humankind is capable of changing the climate, CO2 is not the primary driver of climate change.
As noted by Dr Pielke many times, land use has a tremendous effect on the warming of the globe, and we have to isolate the urban heat islands to analyze what is really going on. If the NCDC has been diddling the data and hiding the real effects of mankind’s huddling masses in urban areas, it is scientific (and social) fraud.
Your social consequences probably revolve around the huge collectives of humans living in restricted spaces.
Geo, I also was interested in the way the urban-rural split started after the 1960’s. To me it suggests that the warmer urban temperatures may be due mostly to air conditioning, which started to become widespread about then. As we all know, air conditioners work by taking heat from inside buildings and transferring it outside — plus all that waste heat from the extra electricity being used. If you look at an old and classic film like rear-window, set I believe in the 1950’s, notice how everyone keeps their windows wide open because no one has air-conditioning. People who grew up in the 1950’s remember going to department stores or movie theaters just to enjoy their air conditioning during hot days. By the 1960’s most people had home air conditioning and air-conditioned cars, so it was no longer a draw.
rc (04:14:19) :
If the first graph correctly shows the UHI effects in urban vs rural stations, why does it begin in around 1965?
Just puzzled why it wasn’t showing up earlier or why it happens all at once.
How old are you? I’m old enough that 1965 is about the time I graduated from high school (1964 to be exact). I grew up on the west coast, but every other year my folks would take the family back “home” to Arkansas, usually during the summer time, for a couple of weeks. We’d visit grandparents, aunts and uncles, and other relatives. Even as late as the mid 1960’s, I do not recall any of them even having window air conditioners, let alone whole house central air and heat. I remember some “swamp coolers,” and sleeping with windows open at night. All of that began to change in the 1970’s. New homes were being built with central air and heat. Older homes began to have window air conditioners, and so forth.
I doubt that the experience in Arkansas was much different than in many other places. In growing up on the west coast (California until 1964, when I graduated from high school, and then 10 more years in Oregon, before migrating back to Arkansas), I never lived in a home that had air conditioning. While I’ve not been back to the west coast, except to visit a few times, I cannot imagine any new homes not being “climate controlled” these days.
And then there is the rise of office towers in the cities. In the 1960’s, few metro areas had all the tall office towers we see today. When I went to school at Oregon’s Portland State College in the mid-1960’s, I don’t recall any really tall towers, maybe no buildings in town with more than 12 stories. As in:
http://en.wikipedia.org/wiki/Wells_Fargo_Building
Most of the skyline you see today:
http://upload.wikimedia.org/wikipedia/commons/thumb/0/08/Portland_Night_panorama.jpg/1000px-Portland_Night_panorama.jpg
was built after 1970.
And that was probably the case in many metro areas throughout the country. When I came to Little Rock in the mid 1970’s, the only “tall building” was the Worthen Bank building, built in 1968. All the taller buildings that now mark the city’s skyline were built after 1970.
This has been repeated over and over throughout all of the mid-sized metropolises of the US. The modern skylines of those cities date from the 1960’s on. Couple that with the change in home (and apartment) construction to central air (and heat), and it is not surprising at all that we’d see this kind of divergence beginning in the mid 1960’s.
DavidM (05:36:12) :
As David points out, I’ve never quite understood why you’d want to sample thousands of sites to show a warming a trend. A notable change in temperature will have to show in single sites when applying appropriate smoothing when analysing a 100 year record. To get a global trend it definitely has to exist in the individual sites contributing to it. If you take a handful in a certain region to rule out local effects I would hope the long term trends would match quite well between nearby sites. One of the clearest indicators for ‘unprecedented’ warming to me would be a site unchanged over a long period of time that showed a notable trend over 100-150 years. From my cursory looks I don’t really anything of significance over the notable 1930’s/40’s peak. More smaller studies such as this, you need to define your sample set well, and others like the surface stations project provide a good summary of historical temperature trends.
This, if confirmed, is going to have major implications, not only for AGW crowd, but for some people on “our side” as well, for example Spencer and Christy. Their satellite record show the warming of 0.22 degrees C per decade since 1979 for the USA 48. If this paper is correct, the rural stations in the USA 48 would have at least 3 times lower warming rate than that of UAH! What confidence we can have in the UAH data set after that? I suppose that rural trend is as close as possible to the real climatic trend. It is somewhat ironic and very worrisome in the same time, that UAH satellite data, allegedly free of any non-climatic bias, are much, much closer to the USA urban and rural-adjusted data, than to the real, unadjusted rural record!
So, as a country’s urban centers increase so does UHIE. I wounder what the first graph would like like for different countries around the world, because not every country has grown at the same rate.
One more issue to think about. Apart from ground stations and the like…what about the scientists in charge?, it seems that nothing changes. Are there not honest scientists any more? …All this is just crazy: Biased ground stations, adjusted records, satellites adjusted to adjusted and biased ground stations…a feedback of lies everywhere. It seems that the best you can do now it’s just go outside suck your finger in your mouth and raise it above your head to feel how the weather is…LOL
Several people here have called attention to the recent satellite-based temperature data. Going from the data produced by the satellite radiation sensors to an estimate of the earth’s atmosphere and surface temperatures is an “ill-posed” mathematical problem. This means that small random errors in the satellite sensor measurements — and these sorts of errors are always present, they can’t be avoided — lead to big, odd-looking, and obviously wrong temperature estimates unless the computer program estimating these temperatures makes some assumptions about what the satellite sensors are really looking at. These assumptions could be that the actual temperatures are not too far from the climate average expected for the place on the earth and the time of year where the satellite is taking data, or that temperatures close together in the atmosphere or at the surface cannot be different by more than a certain amount, and so on. Then, always insisting that these assumptions are satisfied, the computer programs attempt to find the temperatures that do the best job of matching the radiation measurements. Change those assumptions and the programs will produce different temperatures for the same radiation data coming down from the satellite. People who run these large and complicated programs do not like doing this, because it’s all too easy to introduce bugs that result in no temperature estimates at all being produced, but I would not be surprised to find that under the right sort of outside “encouragement” the programmer would be told to make the effort. All the data coming from the satellite systems is highly digitized, making it easy to produce cool graphics and so on, but given the ill-posed nature of the mathematical problem they are solving I would be wary of treating that temperature data as gospel. What skeptics should really be looking at is the raw radiation sensor data coming from the satellites.