GHCN Temperature Adjustments Affect 40% Of The Arctic
By Paul Homewood
Before After
There has been much discussion recently about temperature adjustments made by GHCN in Iceland and Greenland, which have had the effect of reducing historic temperature levels, thereby creating an artificial warming trend. These can easily be checked at the GISS website, where both the old and new datasets can be viewed as graph and table data, here and here.
It has now been identified that similar adjustments have been made at nearly every station close to the Arctic Circle, between Greenland and, going East,via Norway to Siberia, i.e 56 Degrees West to 86 Degrees East, about 40% of the circumference.
So it is perhaps time to recap where we are now.
Background
The NCDC has produced the Global Historical Climatology Network (GHCN), a dataset of monthly mean temperatures, since the 1990’s. Version 2 was introduced in 1997 and included “Methods for removing inhomogeneities from the data record associated with non-climatic influences such as changes in instrumentation, station environment, and observing practices that occur over time “. The GHCN datasets are used by both GISS and HADCRUT for calculation of global temperatures, as well as NCDC themselves.
In May 2011, NCDC brought out Version 3, which “enhanced the overall quality of the dataset”, but made little difference in overall terms. However, only two months later in July, a Google Summer Student, a graduate called Daniel Rothenberg, was brought in to convert some of the GHCN software and make modifications to “correct software coding errors”. The result was Version 3.1, which went live in November 2011. (The full technical report is here).
It is this latest version that has thrown up the Arctic adjustments we are now seeing.
Until December, GISS used Version 2 unadjusted temperatures. Since then, they have changed to using Version 3.1 adjusted temperatures.
Basis of Homogeneity Adjustments
It is worth taking time to be clear why temperature adjustments are made (or should be). As far as GHCN are concerned, they explain their logic thus :-
Surface weather stations are frequently subject to minor relocations throughout their history of operation. Observing stations may also undergo changes in instrumentation as measurement technology evolves. Furthermore, observing practices may vary through time, and the land use/land cover in the vicinity of an observing site can be altered by either natural or man-made causes. Any such modifications to the circumstances behind temperature measurements have the potential to alter a thermometer’s microclimate exposure characteristics or otherwise change the bias of measurements relative to those taken under previous circumstances. The manifestation of such changes is often an abrupt shift in the mean level of temperature readings that is unrelated to true climate variations and trends. Ultimately, these artifacts (also known as inhomogeneities) confound attempts to quantify climate variability and change because the magnitude of the artifact can be as large as or larger than the true background climate signal. The process of removing the impact of non-climatic changes in climate series is called homogenization, an essential but sometimes overlooked component of climate analysis.
It is quite clear. Their algorithms should look for abrupt changes that are not reflected at nearby stations. It has nothing to do with “averaging out regional temperatures” as is sometimes claimed.
GISS also make homogeneity adjustments, but for totally different reasons. In their case, it is to make an allowance for the Urban Heat Island Effect (which is not spotted by GHCN because it is a slow change).
Effect of The Adjustments
Appendix A lists every current GHCN station with records back to 1940,that lie between Greenland, at a latitude of 56 W, around to a point about midway across Siberia at 86 E and which are situated close to the Arctic Circle. The table shows the adjustment made by GHCN for 1940 data. Out of 26 stations, the adjustment has reduced actual temperatures in 23 cases, many substantially. In contrast, 2 remain unchanged and only one has a positive adjustment (and this is insignificant). As a crude average, the adjustment works out at a reduction of 0.70 C.
These adjustments typically extend back to the beginning of the station records (though Reykjavik is an exception) and most continue at the same level till about 1970. ( Some of the Russian stations last longer – e.g. Ostrov Dikson’s disappears in 2009).
By 2011, however, the adjustments disappear at ALL of these sites. In other words, an artificial warming trend has been manufactured.
It is worth spelling out two points :-
1) Within this arc of longitude, there are no other stations within the Arctic Circle.
2) With the exception of Lerwick and Vestmanneyja, I can find no stations, in the region, below a latitude of 64 North with similar adjustments. Why is 64 North significant? GISS produce zonal temperature data, and their “Arctic” zone goes from 64 North to the Pole. Coincidence?
Is there any justification for adjusting?
Trausti Jonsson, a senior climatologist at the Iceland Met Office, has already confirmed that he sees no reason for the adjustments in Iceland and that they themselves have already made any adjustments necessary due to station moves etc before sending the data onto GHCN.
Clearly the fact that nearly every station in the region has been adjusted disproves the idea that these sites are outliers, which give biased results not supported by nearby stations.
GHCN were asked in January to investigate this issue and so far have failed to come up with any explanation. Unless they can do this, the assumption must be that the adjustments have been created by faulty software.
Discussion
In global terms, these few stations make no tangible difference to overall temperatures. However, they do make a significant difference to temperatures in the Arctic, which are derived from a small number of stations such as these and then projected over hundreds of miles.
Across much of the Arctic, temperatures were as high in the years around 1940 as they are now. History should not be revised at the whims of an algorithm.
What should happen next? In my view, GHCN should immediately revert to Version 3.0 until the matter is properly investigated and any issues resolved. They maybe just need to put Version 3.1 down as a bad experience and start from scratch again. I believe they also need to seriously review their Quality Control procedures and question how these anomalies were allowed to arise without being flagged up.
It should not be up to independent observers to have to do this.
References
1) GISS still archive the Version 2.0 data here. (Also GISS, following requests by me and others, have included a link to Version 2.0 on their main site).
http://data.giss.nasa.gov/gistemp/station_data_v2/
2) And can be compared with Version 3.1 here.
http://data.giss.nasa.gov/gistemp/station_data/
3) The adjustments can also be seen in graph format at GHCN here. (The station numbers can be obtained at GISS)
ftp://ftp.ncdc.noaa.gov/pub/data/ghcn/v3/products/stnplots/
Footnote
I originally set this table up yesterday, 9th March. Today I noticed a few had changed slightly, presumably at the monthly update, so have amended them. It appears GHCN are still fiddling with their algorithms as the same thing occurred last month.
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Mosher
‘you can act just like those people who read the Gleick memo and came to conclusions’
Erm so you read them and came to no conclusions ? what? not even ones that support your own preconceptions/biases ? not a very believable human reaction !
‘due diligence ‘
What like checking that they were real or not gained by deception ?
PMSL!
Mosh said;
‘The world is warming. That warming has been going on since the LIA. ‘
Exactly. A point I have made many times. It was pretty warm during much of the the 16th century cooled substantially for much of the 17th century but has shown an upwards trend for 350 years.We can trace it back to the mid 1600’s.
Now when I say that the warming has been going on since the LIA you tell me its ‘anecdotal’ but when you say it thats supposed to be factual?
tonyb
Steven Mosher says read the code.
But the code for the GHCN v3 adjustments has not been released.
This post is not about the global average, it’s about the arctic and the systematic “adjustment” of the warm 1940s.
George says:
March 11, 2012 at 6:34 pm
It appears GHCN are still fiddling with their algorithms as the same thing occurred last month.
They have been changing the adjustment every month. With every passing month than make older temperatures colder. It’s often just a tiny amount each month but it adds up. This graph shows the total CHANGE in NCDC database temperatures since May 2008. You can see that older temperatures have been adjusted colder, modern temperatures adjusted warmer.
http://climate4you.com/images/NCDC%20MaturityDiagramSince20080517.gif
=====================================================================
George, that’s a perfect snapshot of ‘hands in the cookie jar.’ Hard to argue against that graph.
And somewhere pigs must be flying! Anyway, of course what Steve says is true. What is also true is that there are several warming/cooling phases of differing periodicity overlapping and intersecting each other.
* Last Glacial Maximum to the current Holocene Interglacial
* Little Ice Age to Modern Warm Period <– Mosher acknowledged
* 1960’s-1970’s cool period to 1990’s-2000’s warm period
Looks obvious that both items [1] and [2] are still in effect, while item [3] remains in doubt as we may have just turned the corner again towards a cooling in a 30/60 year micro-cycle. It is worth noting that the climate scaremongers dug their feet in just as item [3] switched from cold to warm, how clever.
So just how do the climate scientists propose to account for *all* of these natural pro-warming signals from their work: “Our estimates of that warming get better as we get more data. Our error bars get smaller as we add more data.”, and to what end?
Question: Is there enough room in that total alleged sub 1°C temperature rise during the past century to account for all of these warming signals? Just how does that one degree get subdivided?
[1] – Last Glacial Maximum to the current Holocene Interglacial
[2] – Little Ice Age to Modern Warm Period
[3] – 1960’s-1970’s cool period to 1990’s-2000’s warm period
[4] – As yet unidentified warm/cold phase changes
[5] – Man’s contribution via CO2 and other emissions
What I am asking is this – we have almost a one degree temperature rise, why is that even news at all? That is easily explained by any of the first three items. Perhaps emissions from human beings aren’t all they are cracked up to be (duh!). Looking at these simple facts one might deduce that a true alarmist scenario would be adding in other parameters like a sudden rash of large volcanic eruptions, or even an impact event. And it is easy to see how a well-placed Orbital Parameter (Milankovic, etc) can tip the whole thing badly when it occurs. In my opinion we are really living on the edge, but not the way the alarmists explain it. We are living on the edge of a tipping point to cold, not catastrophic warming.
Barry Brill says: March 11, 2012 at 9:21 pm
“AGW theory suggests warming increases with latitude. If there was no material warming in the Arctic during 1940-2011, that must cast doubt on the global record.”
Doug Proctor says: March 11, 2012 at 10:29 pm
“The consistent warming bias of (especially) GISS used to be denied. But it is unavoidably clear. Each revision increases it. The only way it can be real is if temperature measurements in the past were fundamentally misrepresenting the actual temperature.”
You’re missing what Steven is saying. Posts like this make people think that someone has replaced the old data with new. But they haven’t. GHCN publishes its unadjusted data set, and that is what it says, unadjusted. The original readings.
And you can use these to construct a temperature index. Steven has done it. So have I, and many others. And we get essentially the same result as GISS, without using any of their adjustments.
Philip Bradley says
Note the step change in Archangel temps at the start of Soviet Union around 1920, likely related to the introduction of heavy industry and high density housing for workers.
———–
I a wondering about the historical context for that era and how that might affect temperature readings, not so much actual temperatures.
Around that time we had:
The Great Depression
WW1
WW2
The Russian revolution
Someone like to claim people were concientiously recording temperatures while this was all going on?
GISS simply can’t deal with or handle reality. Period.
Maybe they should stop handling anything else until they can.
The plots in reference 3 above do not seem to exist. All of the subdirectories that I checked were empty.
The “Last Modified” date on all of them reads 12/03/2012 5:14:00 AM.
Fraud, pure and simple.
The most lucrative scam ever, bar none.
It makes Enron and Madoff look like small players.
Lock the b******s up!
Nick Stokes – if you are using unadjusted data that starts 0.7°C higher than GISS adjusted data you ought to get a different result.
If not, it tends to suggest that your method is impervious to data values (like the hockey stick!).
Doug Proctor says:
March 11, 2012 at 10:29 pm
Steven Mosher says … various things.
The CAGW debate is a fascinating social science study in that smart people like Mr. Mosher can drop common sense in favour of intellectual justifications. We know that others’ stories of struggle and achievement show then in better light over time. We understand the bias that benefits. All those working in technical fields know that our projects will provide better results with lower risks the longer we push them.
LOL
Mosher is always pushing what he is intellectually invested in, namely BEST.
BEST is merely a rehash of the same fundamentally flawed data used by HadCRU, GISS, etc, namely min/max temps.
I think someone just said that GISS’s data and formulas….are so bad they have to adjust it….to make it match everyone else’s
I think there is a simple metadata [SNIP]up somewhere behind this , f.x. below is a link to a monthly value time series for Stykkishólmur in Iceland from 1830-1999 at the web site of the Icelandic weather bureau in text for.
http://www.vedur.is/Medaltalstoflur-txt/Stykkisholmur.txt
fetch it, and compare the common values in GISTEMP for the same station
accessible here
http://data.giss.nasa.gov/cgi-bin/gistemp/findstation.py?datatype=gistemp&data_set=14&name=&world_map.x=324&world_map.y=65
Here is a small sample of the first 3 months of the years from 1926 to 1930 from each table
Iceland Weatherbureau GISTEMP SURFACE ANAL.
Year Jan Feb Mar Year Jan Feb Mar
1926 0.2 1 -0.7 1926 -0.2 1 -0.7
1927 -2.4 0.6 2 1927 -2.4 0.6 -2
1928 -1 -0.3 1.3 1928 -1 -0.3 -1.3
1929 1.8 2.1 5.4 1929 -1.8 2.1 -5.4
1930 -2 0.9 -3.3 1930 -2 0.9 -3.3
As can be seen january 1926 and 1929 have the same absolute value but diffrent signs
same for marz 1927, 1928 and 1929, and I counted at least 20 other instances like this in
the entries for the same three months and from 1925 to 1950 , i.e in something like 75 monhtly values there is a different prefix on every third one or so, resulting in a GISTEMP reading close to 11°C lower than the Icelandic meterological service for the month of marz 1929 ( a -5.4 instead of a 5.4 °C) which is biggest and double digit diffrence I spotted , but there are also a significant number of multidegree values the 2 – 7 degree interval.
All in all , this looks most like some of the prefixes are being reversed somwhere, but as there is no acess to the daily records at either place, it is not possible to say where, so GISS could vell be the innocent party, though I would probably wage a small bet on odds that they have been running an errant software on the data, as it is hard to imagine that 23 stations have conspired to send in unidirectional bad data in concert.
I have just done a comparison between the v2 and v3 temperatures for the Ostrov Dikson station, August only because all other months have “999C” lapses.
Brief results: 1918-1956: v3 depresses temperatures by 1.1C.
1957-1974: v3 exaggerates temperatures by 0.6C
1975-1989: v3 depresses by 0.1C
1990-2011: v2 and v3 identical.
Conclusion: v3 adds a warming trend of 1.1C per century.
Repeating the exercise with v3.1, the additional warming trend is 2.4C per century.
If repeated for other high-latitude stations, these adjustments are creating a fake warming trend for the Arctic.
This is the chart showing why Reykjavik needed to be adjusted. The difference between it and its nearest neighbours within 1500 kms.
There is only one tiny change required. This whole algorithm went way off course somewhere and adjusted all of the neighbors up instead of finding the few which were a problem..
ftp://ftp.ncdc.noaa.gov/pub/data/ghcn/v3/products/stn-vs-net/ghcn/62004030000.tavg.raw.WMs.52g.anomaly.gif
Readme file explaining how to read the above chart and why adjustments might be required. Reykajavik fails except for perhaps WWI in 1918.
ftp://ftp.ncdc.noaa.gov/pub/data/ghcn/v3/products/stn-vs-net/README-stn_vs_net.plots.pdf
They seem to get away with basically anything, so why do they bother faking data in low profile?
Nothing seems to touch them, hell even Obama would be jealous…
If anybody would like to check my workings, here’s the method:
For Ostrov Dikson v2: http://data.giss.nasa.gov/work/gistemp/STATIONS//tmp.222206740006.1.1/station.txt
Look for August 1918=4.3C Aug 1919=9.1C Aug 1920=5.4C…… Aug 2011=4.2C
For Ostrov Dikson v3.1
http://data.giss.nasa.gov/work/gistemp/STATIONS//tmp.222206740000.14.1/station.txt
Look for August 1918=4.1C August 1919=8.9C August 1920=3.7C……. Aug 2011=4.2C
Incidentally, the Ostrov Dikson v3 seems to have been ‘disappeared’. It went:
August 1918=3.3C Aug 1919=8.1C Aug 1920=2.9C…… Aug 2011=4.2C
The simplest of spreadsheets, showing the ‘adjustments’ between v2 and v3.1 shows the clumsy hand of the ‘adjustor’. Up to 1956 he’s lopped off 0.3C +/-0.1C. From 1957 on he’s upped it by mostly 1.5C, and from 2009 there’s no fiddle factor. Rather like a bloke who crosses the finishing line at the marathon saying, “What, me? A ride in a taxi? You SAW me come down the finishing straight!”
Steven Mosher wrote: The warming doesnt disappear. It CANNOT. if it disappeared, then UHA would be wrong as well.
Understand. The world is warming. That warming has been going on since the LIA. Our estimates
of that warming get better as we get more data. Our error bars get smaller as we add more data.
Yes Steven, we believe that too. The issue (as you very well know) is what is causing the warming and an important aspect of that is when the warming occurred. If considerable warming occurred before the steep post war rise in CO2 emissions, then why should the current rise be due to CO2? Clearly, reference to UAH (which is what I assume you mean by UHA) is pointless, since that record is only the last 30 years.
In the longer term, the same kind of issue arises with the MWP, which was ‘disappeared’ by the HSG.
When warmists talk about ‘unprecedented’ warming, whilst systematically altering our ‘records’ of the past how should we not be sceptical?
That you ‘answer’ the wrong argument in such a very condescending way reveals you as both rude and less intelligent than you think you are.
Allan MacRae says:
February 11, 2012 at 8:05 am
http://wattsupwiththat.com/2012/02/08/interesting-presentations-from-the-nagoya-workshop-on-the-relationship-between-solar-activity-and-climate-changes/#more-56210
Allan MacRae says: February 9, 2012 at 12:36 am
In this complex case, I suggest that the best test of one’s scientific credibility is the degree to which one can accurately predict future global temperatures.
How many of you are prepared to go on record with your best estimate?
___________________________________________
This is a good start (regarding Nicola’s earleir post).
…
I say there is zero probability of major global warming in the next few decades, since Earth is at the plateau of a natural warming cycle, and global cooling, moderate or severe, is the next probable step.
In the decade from 2021 to 2030, I say average global temperatures will be:
1. Much warmer than the past decade (similar to IPCC projections) ? 0% probability of occurrence
2. About the same as the past decade? 20%
3. Moderately cooler than the past decade? 40%
4. Much cooler than the past decade (similar to ~~1800 temperatures, during the Dalton Minimum) ? 25%
5. Much much cooler than the past decade (similar ~~1700 temperatures, during to the Maunder Minimum) ? 15%
In summary, I say it is going to get cooler, with a significant probability that it will be cold enough to negatively affect the grain harvest.
____________________
Two possible weakensses of Nocola’s approach:
1. Use of Hadcrut3.ST with its apparentl warming bias of about 0.07C per decade. Should also be plotted wth UAH LT as a check of Hadcrut3.
2. Assumption of a humanmade (CO2?) warming component that will keep temperatures ~constant – I wish. I will bet on the cooling yellow line or similar , not the level black line.
BEST has Archangel very slightly cooling since 1920.
http://sunshinehours.wordpress.com/2012/03/12/archangel-trends-using-best-data-very-slight-since-1920/
Brad
Are you sure the first two graphs above markers “before” and “after” are not identical?
It is easy to check the tables on the GISS website. That’s where I got the actual numbers from.
Steve Mosher
I appreciate your comment about GISS being old hat!!
Presumably you would therefore support the whole organisation being shut down.
REPLY: I’d offer to take up a collection for Hansen’s retirement, but he’s already got quite a bit of money squirreled away thanks to his ongoing climate activism – Anthony
I have just received this message from Trausti Jonsson at the Iceland Met :-
thank you for the list, it is very useful for me. The adustments for 1940 in Iceland are way out of line. But I am not so worried about this at the time being – as I still hope that it will be corrected later. But at the time being the overall credibilty of the dataset is very doubtful. For the next few weeks I have a number of deadlines to attend to but after that I should be able to work on the problem.
Best wishes,
Trausti J.
Sums things up pretty well.
Mosher: “Understand. The world is warming.”
Not all of it. ALLIANCE.MUNICIPAL.AP(37645) is cooling at -1.1C/decade since 1980
http://sunshinehours.wordpress.com/2012/03/12/some-of-the-world-is-cooling/