GISS weather data: “homogenization”


Raw temperature data NASA/GISS Angmagssalik

Difference between homogenized and raw data from GISS for San Francisco




For Slioch

This is the difference between the homogenized and the raw dataHomgenization for Godthab Nuuk
Difference between homogenized and raw log data

This is the raw data, showing a decline of about 0.5 K per century.

Dublin Airport

The Irish Hockeystick?

Re 2010 “records”.  Saying that 2010 is heading globally for being the warmest on record  must come as ironic to inhabitants of Dublin[3], which is heading locally for something a low, especially if the last month of 2010 is included in the year as normal and continues cold.
Dublin Airport has bizarre anomalies in its “homogenization” of annual averages which frustrate attempts to look back for high and low temperatures in the historical record.
In the homogenized data[2] the high of 2006 (9.92) beats the high of 1989(9.76), whereas in the raw data[3] the high of 2006 (10.12) does not beat the high of 1989 (10.88).
Similarly there are problems with the “record cold”: in the raw data[3] 2010 is clearly competing for the holder of “cold” record with only 1963 and 1947 colder since the late 1910s. However in the homogenized data[2] 2010 looks unremarkable compared with the 1960s.
A few minutes with a spreadsheet is needed to unpick this. Comparing the raw with the homogenized year by year by subtracting raw from homegenized for each of the 130 years it is clear that the homogenized data has been generated by adding a very clear downward staircase with bogus increments of exactly 0.100 deg and a “step” of 12 years, leaving the early years untouched and the later years lowered, ultimately by one degree, but stopping in around 1988-1991 with an accumulated decline of 1.2 degrees. This gives a bogus decline of 0.8 degree per century(!) over the preceding hundred years. At this point, an upward staircase was added at a much higher slope[3], so that the “adjustment” eventually completely vanished by 2010. However, this means that that homogenized data shows a totally bogus phenomenal rate of rise of 0.6 degree per decade over the last two decades. Kiwigate was, AFAIR, solely about bogus upward “adjustments”. To see a progress downward “adjustment” over a century and then an upward adjustment in two decades, all in the same 130 year record for one station, is brilliant!

[1] Dublin Airport RAW EARLY:

[2] Dublin Airport HOMOGENIZED

[3] Dublin Airport RAW LATE:

San Francisco

San Diego

Richmond, VA

Difference between homogenized and raw data for Richmond, VA


Now here’s an odd thing. Here are the mean surface air temperature readings from Richmond, VA, according to NASA/GISS for the last eleven years. The RAW[1] column shows what the thermometer read. The HOM[2] column shows what it “should” have read, that is, it has been “homogenized” to correct for, erm, whatever homogenization corrects for. DLTA = HOM-RAW. You will see that the correction is always an exact multiple of 0.10 degree, and it goes in downward steps each year (except  2006-7). The effect is that over the last ten years the homogenized has an extra decline of about one degree per decade compared to the actual data. My rhetorical question is: what was the rationale behind this “correction”? For example, what physical process might there be which caused the Richmond thermometer to be consistently over-reading by 0.6 degree (for several decades, not shown here), and then gradually cause it to be more accurate over the last ten until it is spot on this year?  The graph of this is shown here[3].

2000 14.69 15.29 0.60
2001 14.39 14.99 0.60
2002 15.59 16.19 0.60
2003 14.21 14.81 0.60
2004 14.97 15.47 0.50
2005 15.50 15.90 0.40
2006 15.47 15.77 0.30
2007 15.79 16.09 0.30
2008 15.38 15.58 0.20
2009 15.06 15.16 0.10
2010 15.92 15.92 0.00

[1] Raw:

[2] Homogenized:

[3] Delta:

Waddington (UK)

Adelaide Airport

Adelaide Airport, showing how much is added to the raw data to give the homogenized data.

This is such an interesting plot that it makes sense to look at the effect on the temperature chart itself:

Personally I prefer to fit a sine wave with a period of about 120 years through the raw data:


5 Responses to GISS weather data: “homogenization”

  1. Hi Suffolkboy,

    I just stumbled on this today, and it’s great to see your excellent “homogenisation” data mining in one place. If you read this comment, you should be able to see my e-mail address in your wordpress dashboard. When you have a moment, please pop me an e-mail so I can have your address.

    Cheers, CSM

  2. meltemian says:

    Hi suffolkboy – Blackswan posted your link on OL’s site.
    Oh Good – another site guaranteed to make my brain hurt!!

  3. Blackswan says:

    G’day Suffolkboy – Congratulations on the Delta Files…..

    NoIdea gave me the ‘tip’ on your Phil Jones comment on Our Man and here we are.

    For me “homogenization” was always about cows milk until I bumped into Global Warming Fraud and lo and behold, here it is, as your detailed analysis shows. Your work is much appreciated by non-techy swans like me but the implications are obvious – how any of it can assume a mantle of credibility is astounding.

    So too your Comment about the Phil Jones “Lecture” – it’s a ripper.

    Is he actually appearing in public without a kevlar vest? According to him, last I heard the poor chap and his family were in hiding.

    Your description of his appearance is a hoot and I agree, the worst part is the reaction of his audience – same here when the GangGrenes hold forth about our recent Australian natural disasters being the fault of the coal mining industry. I saw one Aussie newspaper article liken the Green/Labor/Marxist government in this country to “a wounded animal – and they’ll fight like one”.

    I think that is also true of the Hucksters and Fraudsters of the Climate Con – though mortally wounded they’ll carry on reinforcing their fraudulent message in the belief that there are enough Useful Idiots in the world to keep the flow of their Funding steady.

    Great to see your new venture SB, and looking forward to your future posts.

  4. suffolkboy says:

    Laithwaite meets David Copperfield meets Dougal from Father Ted. That was the impression I got from the lastest lecture from the Professor Phil Jones, looking very perky and self-assured. The Spalding Gentlemen’s Club hosted the lecture to an audience of 100. The audience age may be greater than that of the Royal Society’s Christmas Lectures to Children, but the similarities were striking. In the 1970s we had Professor Laithwaite trying to convince us that buried in the sea of mechanical noise of the motors there was a new force – antigravity – that was produced by gyroscopes and that it had to be antigravity because no other explanation was consistent with what he was showing. On 4th Feb Professor Jones was trying to convince me that buried in the sea of random noise of the thermometers there was a new trend – Anthropogenic Global Warming – that was produced by carbon dioxide and that it had to be carbon dioxide because no other explanation was consistent with what he was showing. It had to be so because the IPCC said so in their 2007 report. Flipping from stating that it is the long-term trends that matter (when some blip doesn’t fit the story) to homing in on isolated years following a volcano (when some blip does fit the story) and back again was a tactic employed throughout the 90 minutes.

    Yet if you had nudged the curtains, wafted the smoke and looked carefully at the mirrors, and replayed the whole lecture in slow motion you would have seen exactly how an illusionist works. It is not what is shown that matters; it is what is not shown. Just as David Copperfield doesn’t pinpoint the the moment that the switch from the victim to the dummy just before the conflagration, or distracts you with ten dancing girls to hide his escape, Professor Jones doesn’t pinpoint exactly how the MWP disappeared, or the effect of cloud coverage drift over the decades is ignored, or how attempts to move him to explain how Galactic Gamma Rays fit the data better than carbon dioxide, or how other explanations for coral oddities came to be excluded. Instead the audience is blasted with graph upon graph (looking mostly like random noise which invariably flips upwards at the very right), together with a continuous patter about why an even bigger blip centuries ago doesn’t count. But the biggest shock is that he uses the NASA/GISS figures to bolster his claim, oblivious to the bogus exponential upward flip added to most of the air temperature data.

    Yet Jones is not an illusionist like Copperfield. The illusionist obviously knows how the trick works and keeps practising to hide any giveaways. In Jones’s case he seems to sincerely believe totally in what he says. It is the sincerity akin to the devout extremely polite elderly man one can find in any church, a person with who reasoning is futile as under pressure he will just return to regurgitating half-remembered sections of the credo. It was all there last night: carbon dioxide, methane, nitrous oxide, aerosols, sulphate particles, industrial era, NASA/GISS, UHA, satellites absolutely consistent with thermometers, oceans warming, glaciers melting, corals dying, tree-rings, insignficance of the Sun. But these were really just dropped casually into the talk as though the issues was settled, so that the graphs were mere confirmation of what the models projected. Models, “might”, “could”, error-bars, were all part of the scattergun approach to convincing me of the impending catastrophe. Never once was data fraud, named individuals (except Arrhenius) or the possibility of error mentioned. The word Climategate was never once heard in the hall. Everything was settled, except was it 1.5 or 7.5 degrees by 2050.

    Finally, we had glimpses of the Dougal. Every now and then there was a lapse, though whether these were slips of the tongue or a profound misunderstanding of some area of the physics I could not tell. The dynamics of solubility of carbon dioxide in water seemed to have passed him by, leading him into bizarre concepts of “old” and “new” carbon dioxide, apparently justified on the basis of isotopes. Glaciers melting would alone (that is, without Greenland and Antarctica) raise see levels by millimetres. The principle of causality regarding temperature and carbon dioxide in Antarctic ice-cores was simply ignored. I could imagine that arguing with Jones would have been like Father Ted lecturing Dougal on Perspective.

    But the most worrying part is that the audience lapped it up. Having a “distinguished” speaker give a presentation is for many people nine tenths of the route to conversion. As the ex-Sandhurst chap said at the end in proposing a vote of thank, if he had not been convinced of CAGW before the lecture he was now. I fear he spoke for many of the fen dwellers in the hall. Now is not the time to give up!

  5. Badgersouth says:

    Unless you explain in detail exactly how you have “homogonized” the data for each of your graphs, they don’t mean dittlysquat!

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