From environmentalist Jennifer Marohasy’s blog in Australia, please pay her a visit here – Anthony
There has been criticism of the potential for official weather stations in the USA to record artificially high temperatures because of the changing environments in which they exist, for example, new asphalt, new building or new air conditioning outlets. Meteorologist, Anthony Watts, has documented evidence of the problem and Canadian academic, Ross McKitrick, has attempted to calculate just how artificially elevated temperatures might be as a consequence.
A reader of this blog, Michael Hammer, recently studied the official data from the US official weather stations and in particular how it is adjusted after it has been collected. Mr Hammer concludes that the temperature rise profile claimed by the US government is largely if not entirely an artefact of the adjustments applied after the raw data is collected from the weather stations.
Does the US Temperature Record Support Global Warming?
By Michael Hammer
IN the US, the National Oceanic and Atmospheric Administration (NOAA) collects, analyses and publishes temperature data for the United States. As part of the analysis process, NOAA applies several adjustments to the raw data.
If we consider, the above graph, which shows, their plot of the raw data (dark pink) and the adjusted data (pale pink), it is obvious that the adjustments have little impact on data from early in the 20th century but adjust later temperature readings upwards by an increasing amount. This means that the adjustments will create an apparent warming trend over the 20th century. [Click on the above chart for a better larger view, this chart can also be viewed at http://cdiac.ornl.gov/epubs/ndp/ushcn/ndp019.html .]
NOAA state that they adjust the raw data for five factors. The magnitude of the adjustments are shown in Figure 2.
Figure 2. Form of individual corrections applied by NOAA. The black line is the adjustment for time of observation. The red line is for a change in maximum/minimum thermometers used. The yellow line is for changes in station siting. The pale blue line is for filling in missing data from individual station records. The purple line is for UHI effects (this correction is now removed). [Click on the chart for a better larger view or visit the same website as for Figure 1.]
It is obvious that the only adjustment which reduces the reported warming is UHI which is a linear correction of 0.1F or about 0.06C per century, Figure 2. Note also that the latest indications are that even this minimal UHI adjustment has now been removed in the latest round of revisions to the historical record. To put this in perspective, in my previous article on this site I presented bureau of meteorology data which shows that the UHI impact for Melbourne Australia was 1.5C over the last 40 years equivalent to 3.75C per century and highly non linear.
Compare the treatment of UHI with the adjustments made for measuring stations that have moved out of the city centre, typically to the airport. These show lower temperatures at their new location and the later readings have been adjusted upwards so as to match the earlier readings. The airport readings are lower because the station has moved away from the city UHI. Raising the airport readings, while not adding downwards compensation for UHI, results in an overstatement of the amount of warming. This would seem to be clear evidence of bias. It would be more accurate to lower the earlier city readings to match the airport readings rather than vice versa.
Note also the similarity between the shape of the time of observation adjustment and the claimed global warming record over the 20th century especially the steep rise since 1970. This is even more pronounced if one looks at the total adjustment shown in Figure 3 (again from the same site as Figure 1). As a comparison, a recent version of the claimed 20th century global temperature record downloaded from www.giss.nasa.gov is shown in Figure 4.
Figure 3. Magnitude of the total correction applied by NOAA
[Click on the charts for a larger/better view.]
Figure 4. Temperature anomaly profile from NASA GISS
Since the total corrections for the US look so similar to the claimed temperature anomaly, it begs the questions as to what the raw data looks like without any corrections. Does it show the claimed rapidly accelerating warming trend claimed by the AGW advocates? To determine this I took the raw data from the USHCN graph shown in Figure 1 and plotted this using a 5 year mean (blue trace), matching the smoothing in the NASA GISS profile shown in Figure 4. The result is shown in Figure 5. Please note that while the plot is one that I generated, the data comes directly from the raw data from Figure 1 published by NOAA.
Figure 5 Plot of raw temperature data versus time (from fig 1) 5 point smoothing. Vertical axis degrees Fahrenheit. Red line is a linear trend line. Green line is a 2nd order (parabolic) trend line.
Clearly the shape of this graph bears no similarity at all to the graph shown in Figure 4. The graph does not even remotely correlate to the shape of the CO2 versus time graph. The warming was greatest in the 1930’s before CO2 started to rise rapidly. The rate of rise in 1920, the early 1930’s and the early 1950’s is significantly greater than anything in the last 30 years. Despite the rapid rise in CO2 since 1960, the 1970’s to early 1980’s was the time of the global cooling scare and looking at the graph in Figure 5 one can see why (almost 2F cooling over 50 years).
A linear least squares trend line, created using the Excel trend line function (Red trace) shows a small temperature rise of 0.09C per century which is far less than the rise claimed by AGW supporters and clearly of no concern. However, the data shown in figure 5 bears little if any resemblance to a linear function. One can always fit a linear trend line to any data but that does not mean the fitted line has any significance. For example, if instead I fit a second order trend line (a parabolic) the result is extremely different. That suggests a temperature peak around 1950 with an underlying cooling trend since. Which trend line is the more significant one? If there was really a strong underlying linear rise over the time period it should have shown up in the 2nd order trend line as well. This suggests that it is questionable whether any relevant underlying trend can be determined from the data.
It would appear that the temperature rise profile claimed by the adjusted data is largely if not entirely an artefact arising from the adjustments applied (as shown in Figure 3), not from the experimental data record. In fact, the raw data does not in any way support the AGW theory.
Based on this data, the US temperature data does not correlate with carbon dioxide levels. The warming over the last 3 decades is completely unremarkable and if present at all is significantly less than occurred in the 1930’s. It is questionable whether any long term temperature rise over the 20th century can be inferred from the data but if there is any it is far less than claimed by the AGW proponents.
The corrected data from NOAA has been used as evidence of anthropogenic global warming yet it would appear that the rising trend over the 20th century is largely if not entirely an artefact arising from the “corrections” applied to the experimental data, at least in the US, and is not visible in the uncorrected experimental data record.
This is an extremely serious issue. It is completely unacceptable, and scientifically meaningless, to claim experimental confirmation of a theory when the confirmation arises from the “corrections” to the raw data rather than from the raw data itself. This is even more the case if the organisation carrying out the corrections has published material indicating that it supports the theory under discussion. In any other branch of science that would be treated with profound scepticism if not indeed rejected outright. I believe the same standards should be applied in this case.
*********************
Notes and Links
Interestingly, there was an earlier version of the NASA GISS data shown in Figure 4 which was originally published at http://www.giss.nasa.gov/data/update/gistemp/graphs/FigD.txt While this site has now been taken down the data was apparently archived by John Daly and available at his website http://www.john-daly.com/usatemps.006. The data is presented in tabular form rather than graphical form but appears to be either identical or extremely similar to that shown in my Figure 5.
Other contributions from Michael Hammer can be read here: http://jennifermarohasy.com/blog/author/michael-hammer/
[scroll down, click on the title for the full article]
Ross McKitrick, Ph.D. – Quantifying the Influence of Anthropogenic Surface Processes on Gridded Global Climate Data
http://www.heartland.org/events/NewYork08/newyork2008-video.html
Anthony Watts – http://wattsupwiththat.com/
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Also with TOB, I thought both Tmax and Tmin were recorded each day. Is there a link to information how both the older and newer surface station equipment works, and standard procedures for readings?
For the USHCN, it’s all min-max, regardless of system. Therefore it all comes down to time of observation. If TOBS occurs right around Tmax or Tmin, big problems will occur: A spike will “carry over” to the next day, effectively “counting it twice” and wiping out the next day’s “true” Tmax or min.
If you keep measurement time well separated from the hottest and coldest point during the day, there should be no problem.
(It also shouldn’t matter much if it’s morning or afternoon, so long as it is at the midway point between typical Tmax or min periods. But NOAA claims there is a tendency for a lag, so mornings may have a bit of a cool bias and afternoons a warm bias.)
Evan wrote: “If TOBS occurs right around Tmax or Tmin, big problems will occur: A spike will “carry over” to the next day, effectively “counting it twice” and wiping out the next day’s “true” Tmax or min.”
And I think here is exactly where the logic error occurs and why TOBS adds to the magnitude of the record.
Evan, for example you just assumed that the previous day’s Tmax would “swamp” the next day’s Tmax. That is ONLY true if the previous days Tmax is greater than the next. If the following day’s Tmax is higher, then no problem.
Same holds true in reverse for Tmin.
The TOBS methodology is a logical mess. – Anthony
evan that is the new math
of course we do it in our head as 42-3 is 39
oh well.
42= 30+12
12-3=9 9+30=39
got it
To be more precise 30 years refers to the trend we are ‘currently’ in, and 100 years is the trend we predict.
Well, as the master says, It all depends whether you are over 35 or went to a private school or under 35 or went to a public school.
liberal or conservative school ? that is my take, i am 50 and got it in grammar school here.
Why is 30 years the important trend?
Well, it starts right around when the PDO and SO flipped and the warming trend started. It also coincides with the era of satellite measurement. And it is a long enough period of time to make the data statistically significant. (Though it seems to me the ending of the Younger Dryas did in three years what they normally do in thousands and that ought to be statistically significant enough to be going along with.)
I think if the temps fall 5F in the next two years some heads will roll….. lol
maybe they can add 5 to all the station across the board!!!!!!!
never mind the snow in the keys or Bahamas!!!!
That is ONLY true if the previous days Tmax is greater than the next. If the following day’s Tmax is higher, then no problem.
Certainly. (That’s what I meant by a “spike”. I should have made it clearer.)
The TOBS methodology is a logical mess. – Anthony
Gosh, yes. Did NOAA ever release its algorithm for that like sure ’nuff scientists? (Or are we still talking typical NCDC alchemy?)
Anthony,
The co2 bill is in the Senate , we need your work published ASAP, WE ARE OUT OF TIME.
oh well stuff happens!
REPLY: Peer reviewed journals don’t usually run on the authors schedule on anybody else’s – Anthony
[REPLY- Unless of course it’s The IPCC and the Hockey Stick redux! ~ Evan]
liberal or conservative school ? that is my take, i am 50 and got it in grammar school here.
The main difference these days is that in the former case you don’t need to get the right answer to receive full marks.
(“I would have given him a B, but I couldn’t afford the lawsuit.”)
I think if the temps fall 5F in the next two years some heads will roll…..
Nah, they have that covered with The Day After.
evan it’s called promotion !
REPLY: Peer reviewed journals don’t usually run on the authors schedule on anybody else’s – Anthony
Correct and that is how it will be held out of the playing field until there objective has been made.
The mathematics of spin.
I did not get published until I wrote for a conservative paper, they ( the libs.) said my writing was a mess, or unintelligent, or whatever to put it down!
Good luck in getting it through the masher. play by there rules to get it in.
So the red plot should show a slight drop (-.05?) for the introduction of latex paint followed by a smooth increase to +.02 not +.04 during the introduction of MMTS.
The yellow siting plot should probably be inverted, and show a recent further downward adjustment for the MMTS cable issue.
The light blue data infilling plot looks statistically improbable, and should probably be recentred on the x axis.
The purple UHI plot should be included in calculations, and amended to show a serious downward adjustment during the period of rural station dropout.
As to the black TOB plot, I am having trouble conceiving of how an algorithm that does not directly use times of observation for individual stations can generate a meaningful adjustment.
As far as I can see, any significant warming trend shown in the adjusted USHCN record is an artifact of said adjustments. Having said that, I still feel that trying to apply corrections to data from stations rated below CRN-2 is an exercise in scientific futility. It might be useful in supporting political agendas…
So 30 years is arbitrary? I was thinking that thirty years is a very short time in the sense of climate, and 100 is also short, but then at least we are looking beyond the life cycle of a person.
And why add the recent year and drop the old year on the thirty year trend? Why not just add the new year? Just to entertain your math conversation we can refer to it as the 30+X where X equals Year to n. Eh, I don’t think it’ll catch on.
I have done some further reading on Tmax/Tmin readings using the electronic recorder for MMTS sensors. As far as I can see there is the possibility of transposing data from one day to another ie: using one days Tmax or Tmin twice. However this would only occur once if a station changed from morning to afternoon readings. Even if a station operator made observations at almost random times each day, the monthly average should not show a warming or cooling bias. I can see no scientific basis for TOB adjustments for the electronic MMTS system. I will need to read more about the previous measurement system, but I think it is fair to call shenanigans on TOB adjustment after 1985.
bill (20:48:18) REPLY: “One assumes a science blog would use SI units by now !”
OK that’s just disingenuous, An apology is in order from you, Bill
1) NOAA standardizes on F, where the rest of the world and science uses C or K. NOAA’s entire temperature database is measured in F, recorded in F. It is the unit of the United States and for this reason they must conform to that.
It was a mild quip (no snark intentded) hence my attempt at a smiley.
The CDIAC site talks of both C and F in the same document!
The data referenced at http://cdiac.ornl.gov/ftp/ushcn_monthly/hcn_doe_max_data.Z
seems to be in F
http://www7.ncdc.noaa.gov/CDO/mapproduct is in degF
ftp://ftp.ncdc.noaa.gov/pub/data/ghcn/v2/ is in deg C (*10)
I’m sure you are aware of this (an amusing read in comments on occasion!) http://www1.ncdc.noaa.gov/pub/data/uscrn/ushcnsitesurveys/
for example “Please leave the thermograph. Sherry loves it.” “Existing HCN site is marginal. Elderly host does not want new equipment.”
Konrad (20:45:35) : the comparison of USHCN adjustment plots to global data in figure 4 is an unwarranted extrapolation. But the plots in figures 1 to 3 are of great concern.
…
Focusing on minor issues such as Michael Hammer’s curve fitting in figure 5 will not make the issues writ large in figures 1 to 3 go away
If you look at the overlay I did and multiply the height of the adjustment by 5/9 I think you will agree that the adjustment makes no noticable difference to the temperature plot (global) which shows a significant increase.
http://img198.imageshack.us/my.php?image=uhcnadjust.jpg
To try and respond to some of the comments made on this site. Some of you have commented that the trend lines plottd in graph 5 are not warranted. I included them for two reasons. The linear one because AGW advocates are claiming an underlying increasing temperature over the 20th century. If that were the case a least squares linear trend line should show it. Why try second order? Because episodes such as the medieval warm period cause a rise in temperature followed by a fall and the little ice age the reverse. A parabolic or 2nd order trend line would show that up. In both cases the trend line is an extremely poor fit to the data which means they signify very little. If you look at the original I do clearly state that no underlying trend can be determined from the plotted trend lines. Their value (and reason for inclusion) is because they show precisely that.
With regard to one graph in C and the other in F, the problem is that these are not my graphs they are reproduced from cited websites. To make the scales conform I would have had to replot them in which case i would have left myself open to claims I modified the data. As Antony rightly pointed out I was drawing a comparison of shape (not of absolute magnitude) and I was not doing so as a conclusion in its own right but as a trigger to have a look at what the raw data really looked like.
I have seen several comments on both this site and Jennifer’s site implying that I am objecting to a specific correction (usually TOBS) and that claiming the correction is justified invalidates my argument. My concern is more basic. We have here a very comprehensive data record collected over many years. The raw data shows no trend. The data is adjusted and after adjusting shows a trend. Inference, the trend has been introduced by the adjustments made. To use this created trend to justify an hypothesis is very risky and doubly so if the people carrying out the adjustments are supporters of the original hypothesis. Please note that I do not want to imply by this statement that the people involved are deliberately fudging data. I believe them to be honest reputable scientists. However experiments showing how easily unintentional bias can creep into adjusted data are legion. Thats why double blind experiments were devised.
Some things that raise alarm bells for me. Having looked at UHI effects for a medium sized city in some detail it is very clear that the UHI effect is both large and very non linear, increasing in rate in more recent times. For Melbourne the data suggests 1.5C in the last 40 years or 3.75C per century. To use a linear correction does not seem justified. To use a magnitude of 0.06C per century implies only 1 in around 60 sites is affected by UHI (assuming the rate computed for Melbourne is typical). I doubt if one could find 59 rural sites with comprehensive temperature data for each urban site in the USA.
The upwards correction for sites moved out of the city I have already referred to.
A correction for time of day may or may not be justified but why is it continuously increasing at an accelerating rate. Are measurement time continuously changing and at an accelerating rate? And why always to make the temperature warmer?
Why are all the corrections one way – amplifying the supposed AGW signature? Nature is rarely liek that. Why is the UHI correction now deleted?
What about the degrading siting that Antony so elequently demonstrated. Such degradation is likely to increase warming arund the affetced measuring sites. Why is this ignored?
Are there other corrections that should be applied yet have not been?
I can only say again that to create a trend by adjusting data and then using that trend to justify an hypothesis is a very dangerous approach.
A questions for everyone reading this. If this scenario was in relation to testing of a new drug, do you think the FDA would be happy to accept the findings? If not, why should we now. The stakes for our society are far greater than would be the case with an individual drug.
A large part of the correction comes from TOBS. One might expect random variations but it’s difficult to see how it could lead to a strong trend over fifty years. It has been stated on this thread that there was indeed a consistent migration from morning to afternoon readings. For this to occur over half a century does stretch credulity a bit bit I suppose it is possible. So my question is this: can anyone give a link to the actual data and scientific research that this claim is based on?
Of course, as I understand it this discussion is specific to the US temperature record. Is it likely that the same situation (i.e. most of the warming derived from corrections) also applies to the global temperature record?
Finally, is there any other science where vast conclusions are drawn from data that is mostly based on corrections?
Chris
evanmjones (21:35:41) :
The short story is that if measurements are taken in the morning (closer to Tmin), TOBS bias will make them cooler. If taken in the afternoon (Closer to Tmax), the TOBS bias will be warmer.
Evan, I took these measurements for 5 years (1981-1986) while stationed at the USDA-ARS Central Great Plains Reasearch Station in Akron, CO., so I have some experience. I’ve not mentioned this before. The question I have is; if you take a measurement once a day in the morning as is done, the thermometers will record the low of the night before measurement, and the high of the previous day. The previous days high may be recorded “incorrectly datewise” relative to the low recorded presumably after midnight, since the day date changes at midnight (obviously). However, answer this: Why should the temp be adjusted at all? You are still getting the max temp for a 24-hr period, just perhaps not in conjunction with the corresponding 24-hr period low. With my experience I see no valid reason for a TOBS adjustment to alter temperature at all. The TOBS adjustment should presumably only adjust the correlation between max and min for a particular 24 hr period, and not the absolute temp at all. To make it clearer (maybe), when I recorded the max and min temp within the stevenson screen, I recorded an absolute min/max. per day, the same as one who recorded at noon, but either of my min/max may have been attributable to a different 24-hr period. However, the average over the month would be exactly the same.
There’s an unmistakable anthropogenic effect upon climate data.
Well, it TOBS occurs at the right time (well away from Tmax or Tmin, I doubt there should be any adjustment. The times should have been standardized nationally, but were not, presumably because the NWS was trying to predict weather, not record century-long trends to a hundredth of a degree.
(Also, the TOBS problem may not have been realized early on.)
Nick Stokes (22:01:37) :
“On a more serious note though I think the 64 thousand dollar question is whether the adjustments are legitimate.”
Absolutely! You can find details at CDIAC or at NOAA.
There are three USHCN changes that had substantial effect. Allowance for UHI change gave apparent cooling; TOBS and SHAP increased the apparent heating. TOBS is time of observation bias. It is to do with the choice of reading time during the day – chiefly for min-max observations. This wasn’t standardised for US stations, and changed over time.
….
Absolutely not!
Focus on just one: TOBS. You claim that the data needs changing “It is to do with the choice of reading time during the day – chiefly for min-max observations. This wasn’t standardised for US stations, and changed over time.”
We see above that TOBS “corruption” over the century accounts for almost all of the supposed AGW increase that will now cost us 1.3 trillion dollars.
So, prove it.
Show exactly how with the numbers for the entire US stations, not with some abstract unsubstantiated claim, are adjusted. Calculate exactly why the TOBS correction increased continuously ONLY through the last half of the century century – when reading times changes both ahead and behind noon, reading times DID NOT change continuously over the nation but in ones and two’s at isolated stations, changing both ahead and behind, and once changed, did not change back. A single correction for time at a single station is NOT a continuous increase for ALL stations across the WHOLE country that continuously INCREASES with time.
What? Is EVERYBODY now reading a max/min thermometer ever earlier in the morning every day, only that the previous day’s max and min both changed because the thermometer was read ever earlier every day over the whole period?
2) UHI is now NOT corrected. Why? It is the ONLY effect that HAS increased linearly with time.
3) UHI “correction” was NEGATIVE for ALL data from 1900 through 1970. Why? That UHI correction was NEGATIVE (the flip chart at the top of the threads show ONLY the the early temperature was corrected down, the later temperatures uniformly were “corrected” up. Show us why.
Conclusion: Several writers above claim that there is no corruption, no deliberate falsification.
I would change that: It is up to the AGW community to prove beyond a shadow of a doubt that the AGW community has NOT falsely corrupted the data it is using to claim a 1.3 trillion dollar tax increase.
We KNOW absolutely that many previous AGW-favorable studies have been falisified data, falsified numerical analysis, falsified conclusions from the analyzed data, and have been (deliberately) written to exaggerate certain pre-ordained conclusions. Your (the AGW community of extremists) track record shows that the burden of proof of accuracy lies on your side.
Look at the chart of raw vs adjusted temps again: click
Note that the highs and lows all match the raw data [the red squares] prior to about the early 1960’s. But some time after that, the official record starts getting “adjusted.”
But notice that it is only the high temps that are adjusted higher. The low temps are not adjusted lower, they match the raw data.
The net result is to show more warming than has occurred.