Spurious Warming in the Jones U.S. Temperatures Since 1973
by Roy W. Spencer, Ph. D.
INTRODUCTION
As I discussed in my last post, I’m exploring the International Surface Hourly (ISH) weather data archived by NOAA to see how a simple reanalysis of original weather station temperature data compares to the Jones CRUTem3 land-based temperature dataset.
While the Jones temperature analysis relies upon the GHCN network of ‘climate-approved’ stations whose number has been rapidly dwindling in recent years, I’m using original data from stations whose number has been actually growing over time. I use only stations operating over the entire period of record so there are no spurious temperature trends caused by stations coming and going over time. Also, while the Jones dataset is based upon daily maximum and minimum temperatures, I am computing an average of the 4 temperature measurements at the standard synoptic reporting times of 06, 12, 18, and 00 UTC.
U.S. TEMPERATURE TRENDS, 1973-2009
I compute average monthly temperatures in 5 deg. lat/lon grid squares, as Jones does, and then compare the two different versions over a selected geographic area. Here I will show results for the 5 deg. grids covering the United States for the period 1973 through 2009.
The following plot shows that the monthly U.S. temperature anomalies from the two datasets are very similar (anomalies in both datasets are relative to the 30-year base period from 1973 through 2002). But while the monthly variations are very similar, the warming trend in the Jones dataset is about 20% greater than the warming trend in my ISH data analysis.
This is a little curious since I have made no adjustments for increasing urban heat island (UHI) effects over time, which likely are causing a spurious warming effect, and yet the Jones dataset which IS (I believe) adjusted for UHI effects actually has somewhat greater warming than the ISH data.
A plot of the difference between the two datasets is shown next, which reveals some abrupt transitions. Most noteworthy is what appears to be a rather rapid spurious warming in the Jones dataset between 1988 and 1996, with an abrupt “reset” downward in 1997 and then another spurious warming trend after that.
While it might be a little premature to blame these spurious transitions on the Jones dataset, I use only those stations operating over the entire period of record, which Jones does not do. So, it is difficult to see how these effects could have been caused in my analysis. Also, the number of 5 deg grid squares used in this comparison remained the same throughout the 37 year period of record (23 grids).
The decadal temperature trends by calendar month are shown in the next plot. We see in the top panel that the greatest warming since 1973 has been in the months of January and February in both datasets. But the bottom panel suggests that the stronger warming in the Jones dataset seems to be a warm season, not winter, phenomenon.
THE NEED FOR NEW TEMPERATURE RENALYSES
I suspect it would be difficult to track down the precise reasons why the differences in the above datasets exist. The data used in the Jones analysis has undergone many changes over time, and the more complex and subjective the analysis methodology, the more difficult it is to ferret out the reasons for specific behaviors.
I am increasingly convinced that a much simpler, objective analysis of original weather station temperature data is necessary to better understand how spurious influences might have impacted global temperature trends computed by groups such as CRU and NASA/GISS. It seems to me that a simple and easily repeatable methodology should be the starting point. Then, if one can demonstrate that the simple temperature analysis has spurious temperature trends, an objective and easily repeatable adjustment methodology should be the first choice for an improved version of the analysis.
In my opinion, simplicity, objectivity, and repeatability should be of paramount importance. Once one starts making subjective adjustments of individual stations’ data, the ability to replicate work becomes almost impossible.
Therefore, more important than the recently reported “do-over” of a global temperature reanalysis proposed by the UK’s Met Office would be other, independent researchers doing their own global temperature analysis. In my experience, better methods of data analysis come from the ideas of individuals, not from the majority rule of a committee.
Of particular interest to me at this point is a simple and objective method for quantifying and removing the spurious warming arising from the urban heat island (UHI) effect. The recent paper by McKitrick and Michaels suggests that a substantial UHI influence continues to infect the GISS and CRU temperature datasets.
In fact, the results for the U.S. I have presented above almost seem to suggest that the Jones CRUTem3 dataset has a UHI adjustment that is in the wrong direction. Coincidentally, this is also the conclusion of a recent post on Anthony Watts’ blog, discussing a new paper published by SPPI.
It is increasingly apparent that we do not even know how much the world has warmed in recent decades, let alone the reason(s) why. It seems to me we are back to square one.



Manfred,
the picture you linked shows the pattern of warming in the case that GHG are the primary driver of warming. So, you assume that IPCC is basically right in attribution of warming to GHG.
Second, dr Spencer in his analysis in this comment asserts that correctly calculated surface trend for the USA should be roughly equal to the currently reported UAH satellite trend. If this is so, then, according to your hypothesis, predicted tropospheric warming should be about 0.37 or 0.38 degrees K per decade (1.7 x surface), not 0.22, as reported by Spencer and Christy. Are you suggesting that dr Spencer actually wanted to say by this analysis that his own satellite data set UNDERESTIMATED the real tropospheric trend by almost a half?
‘mike roddy (09:14:21)
Even according to Spencer, it’s still warming, so what’s the point? Glaciers are melting, antarctic ice is calving, and birds and plants are migrating north. Humans are the cause.
Deal with it, wattsupwiththat readers, or risk becoming increasingly ridiculous’
I’m assuming that you are assuming that “CO2 Drives the Climate”?
Politicians couldn’t give a rats!
Sorry, it’s pointless, it’s just another tax until the revolution.
DaveE.
Stephen Wilde (08:13:07) :
“Or would satellite sensors do the job well enough ?”
Hey Stephen, should have mention you in there (on oceans). I agree, satellites would be the last choice.
I included satellites just to give a hypothetical system an alternate view if someone didn’t understand the one described on the ground. I wanted everyone to think of the theory, not a specific implementation. How is it best to measure this globes temperature? Is it even possible? If so, how. How with the least error so no adjustments needed.
I had to jump out of the box. Whole point of that was to have everyone stop and say, wait, what in the world are doing? We are going in circles! Or another way to say it is performing adjustments on top of adjustments. Crazy! This whole process has bothered me of late and I just had to come up with a possible alternative.
It’s not meant to be perfect. Add to it. Change it. It’s just a start so we don’t keep thinking of the same broken system with layers on layers of adjustments!
telecorder (09:04:23) :
Thanks. Appreciate that at least someone stopped and read it. Didn’t know if it was just a hair-brain idea or not, well, yes, I think its close. I enjoy theoretical physics, it is a design created this morning for the public to modify, and most of all, stop and think. It may never be physical but in theory it’s what we need to approach.
May I suggest a very simple way to avoid any Urban Heat Island effect ? it would be to exclude any urban station, and only focus on pure rural sites !
Perhaps too simple ?
daniel
Quite simply.
Temperature alone has NO relevance
Never has & never will!
My tuppence.
DaveE.
Daniel, you would have to control for climate zone affect. This can cause your “random” sample to be not random at all. One of the main pitfalls in data collection is to assure you are taking from a random sample. GPS address would become a key measure of randomness if you selected only rural stations. That would tell you if your data set is randomized for longitude, latitude, altitude, and proximity to local micro-climate parameters such as large bodies of water or mountain shadows. Not to mention proximity to homemade truck sized BBQ’s for roasting quarters on a spit.
Remember, sensor GPS address can attenuate or accentuate weather pattern variation drivers (such as greenhouse gases, humidity, clouds, El Nino/La Nina, Jet stream influences, pressure cells, topography, etc). So you must randomize through the climate zones and microclimates.
Daniel: “May I suggest a very simple way to avoid any Urban Heat Island effect ? it would be to exclude any urban station, and only focus on pure rural sites !
Perhaps too simple ?”
Or perhaps too dangerous for so many vested interests in climate science industry…
Hello Everyone,
This is my first time posting at WUWT. I live in Montreal, and have been an “avid lurker” on WUWT for a long time (since the NorCal days, actually). I’ve sometimes had the urge to submit a comment, but someone else has always said more or less what I would have, and without much delay, so there was generally no need. I greatly appreciate the existence of this blog and the work that it does. In some sense, I feel that I already “know” some of you, and I find myself looking forward to posts from various individuals. That would make a fairly long list. In particular, though, I have liked almost everything written by Willis Eschenbach, including his recent semi-rants regarding Drs. Ravetz and Curry, and I religiously “click” all of Smokey’s links. 🙂 I am greatly impressed by the thought processes exhibited by many of the contributors, to say nothing of their concern for the integrity of Science. The only mild criticism I might make is that people sometimes spend way too much time feeding trolls, but I suppose that’s rooted in good intentions. (It would also be nice if we could search the site for more than the words contained in post titles, but I seem to remember that Anthony is somewhat at the mercy of other parties in that regard, so I won’t enter a full-blown complaint.)
OK then, introductions done, I am responding to the request by Carsten Arnholm, Norway (04:36:34) regarding the proper way of finding an average temperature. Before doing that, I would like to say that I’m a physicist, and I am thus not entirely comfortable with the notion of finding an average temperature for anything beyond one thermometer at one location. Everybody seems to be doing it anyway, however, and I’ve been known to say things like “It’s been hot today.”, which is tantamount to making a comment on the temperature across a non-infinitesimal region, so if you want to define such a thing and calculate it, here is my take on how it should be done (for that one thermometer).
::
The Lagrange Approach:
To calculate the mean value of any quantity over some interval, the ideal situation is to have a continuous function, which would be integrated over the full interval and divided by its “length”. For daily temperatures, that would mean integrating over 24 hours and dividing by 24. In practice, if only a finite number of equally-spaced readings are available, the integration then becomes a weighted sum of the individual values, a form of numerical quadrature, as it is called.
– The weights are determined by the number of points available and the function used to represent the entire set of values for that day. If we use a polynomial fit, the order of the polynomial can be anything up to one less than the number of measurements used. We can fit a straight line to two points, a parabola to three, and so on. This leads to well-known results such as the Trapezoidal Rule, Simpson’s Rule, etc.
– In Dr. Spencer’s case, there are readings every six hours, starting at Midnight, which effectively gives 5 points per day (or 4 intervals) since the two Midnights would define the start and end of the data set for an individual day. In this case, a quartic (4th order) polynomial can be used. The procedure for doing this is to find the coefficients of the Lagrange Polynomial that exactly reproduces the original five values. There are many ways to do this, some more efficient than others.
– This polynomial is then used in place of the actual continuous function that would give the temperature at any instant, but because it (the polynomial) is an explicit function, it can be integrated over the whole day, and the weights that should be assigned to each of the five readings can be found. If we use Dr. Spencer’s every-six-hours approach, the weighting formula (starting at 00hrs and going to 24hrs in steps of 6hrs) works out to:
T(avg) = {7T(00) + 32T(06) + 12T(12) + 32T(18) + 7T(24)}/90
::
The Chebyshev Approach:
The Lagrange procedure described above is perfectly workable and sound. There is, however, another method that allows for simple arithmetical averaging of the temperature values, and which gives equally valid results. In this case, however, the weighting is accomplished by taking the readings at non-equally-spaced times within the 24-hour period. In other words, instead of unequal weights, we use unequal intervals, but it accomplishes the same thing.
– The time-values at which the readings should be taken are found from the roots of a group of functions called Chebyshev Polynomials (or variant spellings). With four readings, the 4th-order polynomial is appropriate, and is given by f(x) = x^4 – (2/3)x^2 + (1/45). Note that this function is not intended to represent the temperature itself, but rather its roots are used to determine the times at which measurements should be made. As given, it is defined on an interval from x = -1 to +1, so adapting it to a 24-hour time-period would put t = 0 at Noon, and the end-points at -12 and +12hrs, thus covering a “self-contained” day centered on Noon. Note that there would be no reading at Midnight. All four readings would be made “inside of the day”.
– The roots of this polynomial are approximately: +/- 0.18759 and +/- 0.79465, which when translated into time-values would result in the following optimal choices for observation times:
(2:28AM, 9:45AM, 2:15PM, and 9:32PM) or (02:28, 09:45, 14:15, and 21:32)
Readings taken at these times can simply be averaged (just add them up and divide by 4), and would give the best accuracy available with four readings per day. Whether it might be practical to obtain readings on such a precise schedule is, of course, another matter.
::
Try It At Home:
If you want to check the accuracy of these procedures, you can make up functions yourself and try them out. Both will give exact results if the actual function is a polynomial of order lower than five. They can also be used as approximations for any funtion you like, including non-symmetric transcendental ones, as long they aren’t “pathologically wiggly” or contain singularities. If you pick something that can be integrated exactly by some analytical method, you can compare the three outcomes, and you will find that they give very similar results.
Example: Find the average value of f(x) = exp(x) + cos(x) on the interval (-1,1).
2.0166706 – Chebyshev Method
2.0166722 – Analytical Result
2.0166745 – Lagrange Method
::
Final Comment:
I would not personally consider such calculations to be valid with fewer than four readings per day because of the Nyquist sampling/aliasing issues that have been previously pointed out by E.M. Smith, “jordan”, and others. And, of course, “if I were God”, I would ban the “two-readings max/min thing” to oblivion. But that’s just me. 🙂
dr.bill
PS: To 10 decimals, the roots of the Chebyshev 4th order polynomial are: +/- 0.1875924741 and +/- 0.7946544723. Any standard textbook on Numerical Analysis intended for physicists, engineers, chemists, or geologists will have full explanations of these methods. Look in the Interpolation and Numerical Quadrature sections. Several other sets of special polynomials (Legendre, Hermite, Laguerre, …) can also be used for such purposes, and they are sometimes collectively referred to as Gaussian Quadrature methods.
” vigilantfish (12:39:39) :
Why would you want to further comlicate things?”
Forget about global average temperature and focus on average temperature changes for the global population of measuring sites.
I’m trying to simplify as I sure it’s probably possible to find enough site characteristics so that some could argue that each site is unique which would get us nowhere.
May I suggest that if a site is rural now it be classed as always been rural and worldwide the number of such sites would be large enough to calculate a reasonably accurate average warming/cooling trend for these sites (forget about grid squares).
Say one then found that rural sites averaged small increase, transition sites were steepest and always urban averaged between the other 2 then I believe it reasonable that UHI has been demonstrated, measured and characterised and most importantly such an average measure of rural temperature change would give a reasonable bound on anthropic CO2 warming. Of course other results might be found and need to be explained but what odds would you give me that rural weren’t lowest growth?
If a site is urban now then it would be known if it used to be rural at some point and if so it’s a transition site.
If a site is known to have always been urban then class it as urban.
By averaging each class seperately you’d get 3 measurable comparative behaviours.
Of course one could just look at sites that are currently rural as Daniel (14:45:17) : suggests which I’d be happy as a yardstick for AGW growth. But I’d suggest the urban evidence is needed to help fully explain results currently provided by UEA, GISS etc etc.
And I ask again, Who is denying access to such raw data, as certainly some seems to be available judging from
http://wattsupwiththat.com/2010/02/26/a-new-paper-comparing-ncdc-rural-and-urban-us-surface-temperature-data/
Amino – “There’s a problem with his math—-in 10 minutes from now USA, not Canada, must win the gold today”
Hmmm, looks like The Team may be onto something here eh? Torture, toture, ah, there…
Sorry, we won!
dr.bill (15:56:52) :
Excellent! Excellent! You just cleared up a problem I have had for a long time concerning Chebyshev polynomials. Thanks.
Apparently you have reproduced Menne, Williams and Palecki’s finding that electronic temperature sensors have a slight cooling bias.
REPLY: Josh, knowing you, apparently you’ll just take that wrong impression and shout it from the rooftops. Let me be clear. Menne et al used an incomplete dataset against my wishes, denying my right to publish first. At 88% the network looks a lot different. If the situation was reversed, you are your cronies would be all over me, telling the world how terrible I am for doing such a thing. Yet you and your band of anonymous bunny trolls give Menne a free pass for his actions because you side with the findings. Such integrity. Now back to your hole bunny boy. Watch out for flying cabbages. – Anthony Watts
mike roddy (09:14:21) :
“Even according to Spencer, it’s still warming, so what’s the point?”
The question isn’t whether it is warming or cooling, the question is whether it is warming or cooling in an historically unprecedented way.
Scenario A)
Total Global Oil reserves are burned up in 50 years. Total world coal reserves burned up in 113 years. CO2 emissions problem solved. Their won’t be any more Oil or Coal to burn.
Somewhere between now and the time oil and coal run out Clean Nuclear or Affordable Solar become a reality. The world switches.
Scenario B)
The world will burn up if we don’t invest in expensive technology now.
Somewhere in the middle is probably reality…how fast we are warming dictates which road to take. We will get off of fossil fuels in the next 100 years no matter what.
” Ivan (15:52:24) :
Or perhaps too dangerous for so many vested interests in climate science industry…”
A good headline would be ‘Insignificant global manmade CO2 effect on rural thermometers’. From that most folk would understand from that AGW was dead.
Trolls are like Furbies. If you pay attention to them they do funny things. It’s like having a hamster in a roller ball cage meandering about the classroom. They continue to be entertaining if you feed and water them now and then.
Pamela Gray (15:45:05) :
Daniel, you would have to control for climate zone affect. This can cause your “random” sample to be not random at all. One of the main pitfalls in data collection is to assure you are taking from a random sample. GPS address would become a key measure of randomness if you selected only rural stations. That would tell you if your data set is randomized for longitude, latitude, altitude, and proximity to local micro-climate parameters such as large bodies of water or mountain shadows. Not to mention proximity to homemade truck sized BBQ’s for roasting quarters on a spit.
Pamela, respectably I must disagree here. You are talking of random samples. I am assuming you are saying cities must be included in the sample because if left out, you would not have a random sample. Exaggerate the example. Think in your mind the UHI is twenty degrees. UHI pictorial much like a big bump over the city. Anthony has a couple of good illustrations of this. Now, when wind is blowing, there is little UHI effect, the heat doesn’t create the bubble. When there is no wind, you have full UHI effect. If your objective is to accurately as possible measure the world’s temperature, why would you include cities in your measurements? The heat from the city will continuously be dispersed to the surrounding rural locations, spread out and smoothed. To leave them in, the displacement of the measurement would never be more than the excess heat you see in the bubble over the city, but it would add large amounts of error, now depending on the wind and its speed. Error and complexity has sneaked in, because the cities were included.
Now the rural, generated-heat-free sites, they must be randomly distributed or at least form an evenly covered grid as close as possible. Am I missing something?
Now about the micro-climates, unlike the UHI effects of the cities where extraneous heat is created, they are part of the world we are measuring and do not create heat of themselves. Every point on this Earth is part of some micro-climate. I don’t see why you are including them as something specially handled.
This is a good example how seemingly most have accepted as real and necessary errors and deviations that can be eliminated if looking at the problem in a new light. I think Daniel is correct. You seem to be in the mind-set of controlling, not thinking of a measurement system that needs no controlling, the system handles itself, and of course, all of the above is only in proper physics and science.
Pamela Gray
The hamsters are also distracting the students,the trolls know what they are doing,the intelligent ones do anyway.
Furbies-hehe
Remember the subliminal messages implanted by the Japanese?
Some people actually believed that.
son of mulder (16:37:55) :
“And I ask again, Who is denying access to such raw data, as certainly some seems to be available judging from ”
For per-station daily raw data, I have only found sites (NCDC/NOAA) wanting to purchase the data or order CDs or are only of recent years. If you can find an explicit link to a page or ftp directory, please let us know. Some now have .gov, .edu, .org domain limits for access but can’t recall exactly where.
This comment – “Eli Rabett (16:59:39) :
Apparently you have reproduced Menne, Williams and Palecki’s finding that electronic temperature sensors have a slight cooling bias.”
is a bit off-putting. For it can be taken in more then one way. Anthony, if you have submitted your paper for review, it could be taken that once again, The Team has been discussing others’ works, before publication! If so, then the S**** better hit the fan fast and HARD!
Another way of looking at it is, if the electronic sensors actually showed a cooler temp. when put into operation, like the satellite data, I personnaly would trust the thermistors. Maybe mr. rabbit, the temps were actually cooler…..
Peter Miller (13:09:46) :
rbateman (11:17:27) :
Peter Miller (10:27:49) :
Not surprisingly, global temperatures for January and February this year are higher than normal.
Where?
Everywhere in Australia for one – they are close to the Pacific El Nino.”
Where in Australia exactly are temperatures higher than normal? Certainly not where I am, and today, 1 day after the end of summer, it rose to a “scorching” 19c in Sydney, possibly 22c in the inner west. That’s NOT usual Summer/Autumn temperatures. But if you want to believe KRudd747, Mzzzz W(r)ong, Mzzzz Gillard, the now demoted Environment Minister, Mr Garrett and the heavily biased Australian MSM that “our beds are burning” you are free to do so. Spring was a warm, summer was a lot cooler than usual but was horidly sticky with humidity up to 95% at times. Last summer was pretty cool too and just like last summer, there were almost no flies. I think if “summers” continue to be this cold I’ll forget how to do the “Aussie wave”!!!
Lets see where this winter heads. I’ll predict that we’ll see an early start to the snow season in Victoria and New South Wales possibly up to 4-6 weeks early, maybe earlier.
“mike roddy (09:14:21) :
Even according to Spencer, it’s still warming, so what’s the point? Glaciers are melting, antarctic ice is calving, and birds and plants are migrating north. Humans are the cause.”
As we say in Aus, yeah right!!!!
Dear Dr. Spencer-
I am a student in Conservation Biology at Victoria University, Wellington New Zealand and I just wanted to let you know how much I appreciate the work that you have done here.
Thank you.
Orkneygal
Wren (13:04:31) :
“I believe Ivan’s question was a about the difference between UAH and rural ground records for the U.S. over the 1979-2009 period. Do you mean UAH “should” warm 1.6 times faster than rural stations in the U.S. over this 30-year period?”
It should have warmed 1.7 times faster. Actually, UAH has even warmed slower, what is another strong indication, that ground based measurements have a strong warming bias.
Response to Patrick Davis re Australia – Average February 2010 temperatures:
City Min Max
Alice Springs* +0.6 -0.8
Adelaide +1.9 +2.1
Canberra +1.9 +2.1
Darwin +1.1 +1.2
Melbourne +1.8 +2.2
Perth +0.6 +0.5
Sydney +2.4 +1.7
All figures in degrees C
* Almost 5 times average rainfall in February. Source: Weatherzone