Wanderings of a Marseille January 1978 temperature, according to GHCN-M

This post is still “under construction”, but published early to expand on a comment made at WUWT. This note will be removed when the post has been completed. As I want to further automate the production of these station plots to speed up completion of the post, I’ll publish it now and add further discussion afterwards. (The June date shown above is when I first saved this as a private post)

Temperatures quoted by NOAA and others are “what would have been measured in the past by systems in use today”, so it is not unreasonable for the numbers to change frequently.

It does however seem unreasonable that these past numbers should change quite drastically overnight, then in a short time again change quite drastically overnight, then in another short time …


Click the image (and later images) to view full-size

That green box shown early in 2015 corresponds to a sudden jump in the GHCN-M adjusted value for January 1978, from 5.78°C on January 5th 2015 to 6.41°C on January 6th 2015, followed by a similar drop, from 6.49°C on February 9th 2015 to 5.77°C on February 10th 2015. Note how the January 1978 temperature changes frequently in GHCN-M v3, even overnight, and that the changes may include correction for both “urban heating” and “urban cooling”, seen when the adjusted value become greater than or less than the unadjusted value [My understanding is that Pairwise Homogeneity Adjustment may also include adjustment for urban heating/cooling as well as instrument changes, relocation, TOBS correction, etc]. Anyone willing to suggest station relocations take place this frequently? Problems with Pairwise Homogeneity Adjustment seem more likely.

This behaviour is not a peculiarity related to the January 1978 temperature. The other 1978 monthly temperatures behave similarly, as seen below (each month is shifted slightly down, in a different colour, for visibility – without this offset all would coincide)


This post examines the behaviour of GHCN-M adjustments for past temperatures at Marseille and nearby (in the climate data sense) stations, using saved GHCN-M data sets. The choice of Marseille arises from a blog post LE GISS ET LES SÉRIES LONGUES DE TEMPÉRATURES. I have seen similar behaviour closer to home with past data for Irish stations, but illustration using an Irish station would have restricted the choice of nearby stations to a generally easterly direction, while choice of Marseille provides nearby stations around the compass in France, Spain, Italy and Switzerland. There is no special reason for choosing the past temperature values for January 1978 – I simply took a year from the plotted temperature records for Marseille in that blog post, and used that year for other nearby stations as well. I chose January as the first month in each record, along with December easiest to locate when performing manual checks. In retrospect, a later month in the year might have been a better choice – working through stations I noticed some without January and/or December values. I’ll look at these again later more carefully. My guess now is that these may be stations not manned in winter. I have pointed out to the owners of that blog (the post itself did not provide an opportunity to add comments) that GISS are using the adjusted GHCN-M data as input, and that this, rather than the Gistemp processing, may be the source of the variations discussed in that blog post. Whether this choice of input is wise is another question. MarseilleJan78inJan15 MarseilleJan78inFeb15 Recent values do not display this instability. January 2015 for example remains 7.60°C in GHCN-M adjusted files from February 10th, the date the value first became available, until now. It will be interesting to see whether version 3.0.0 has reduced this instability in past adjusted values or not. As these jumps seem to occur in the first part of the month, I will update here around mid-July. In both cases, the second day is the day an additional item of raw data becomes available. These additional items are not outliers for Marseille. On January 6th the value for December 2014, 8.90°C, arrives; on February 12th, the value for January 2015, 7.60°C. 8.90°C is 0.86 standard deviation units above the mean of December values, 7.60°C is 0.57 standard deviation units above the mean of January values. Relatively few values for other stations are added or changed  on either of these dates. (discussion of these added or changed values coming) One noticeable feature of the adjusted data is that values are missing from May 1970 to March 1971, although values for these months are present in the unadjusted data. With GHCN-M v3.0.0 these values have quality control flag X (= pairwise algorithm removed the value because of too many inhomogeneities). This information was not shown for previous GHCN-M versions. The temperature values in the GHCN-M data sets are shown and discussed here, rather than anomalies. The changing base means which would be subtracted to calculate anomalies are tabulated below for the four dates discussed and for four base periods.

ghcnm.tavg.v3.2.2. 1951-1980 1961-1990 1971-2000 1981-2010
20150105.qca.dat 14.3 14.4 14.8 15.2
20150106.qca.dat 14.9 15.1 15.3 15.4
20150209.qca.dat 15.0 15.1 15.3 15.4
20150210.qca.dat 14.2 14.4 14.8 15.2

Abrupt overnight changes are not simply an artifact of one station, Marseille. (Gistemp values will be added to the images below. Only the first, Marseille, image shows these for now. The data for v3.0.0 which I discovered I had retained will also be added to all images) MarseilleNeighbours The period 1971-1980 is missing from the Salon record, which is not shown in the GISS list above. Toulon has stable adjusted values. Mont Ventoux has data from 1949 to 1968 only. Nimes/Courbes has stable adjusted values, Montpellier is missing data from 1898 to 2000. Nice has stable adjusted values. Mont Aigoual is the closest station displaying jumps in the Pairwise Homogeneity adjusted values for January 1978. (More comments coming here and below between station images) Aigoual Torino/Bric does not appear in the GISS list above as it is dropped during Gistemp processing. I have included it here as it shows a station which is generally unadjusted, but with two dates where an adjusted value departs from the unadjusted value. This would not seem unreasonable behaviour for an automated adjustment process – two “glitches” among more than 500 data sets examined here. There are also more than 160 dates on which an adjusted value for January 1978 is missing. TorinoBLyonMontseny StBernardCh GenovaS Ajaccio ToulouseB GeneveC Barcelona PuyDeDomeAlghero MilanoLMahon

Pisa has missing January values for 1978 for some 2014 and 2015 datasets, but these values are not missing in later 1978 months.PisaJan PisaFebPisaMar


and going further than the GISS list above  (these stations will be moved to a supplementary post when more are added)Dijon Bordeaux Nantes

For anyone wondering about the possible effects of metadata location errors, this post is concerned with GHCN Pairwise Homogeneity adjustments rather than Gistemp adjustments. There are location errors in the metadata for some of the stations shown above. A commenter called Harry at another blog wrote:

I found the computer code for the Pairwise Homogeneity Adjustment (PHA) algorithm they use. It is on the NOAA website

My response to that was:

The code on the NOAA website appears to be v3.0.0, not the code currently used. I was tempted to download and run this code to try to determine the cause of these erratic adjustments, but thought better of it in the absence of current code. Having downloaded and recoded the Gistemp code with additional diagnostic output, I am aware of the scale of such an undertaking. It may come as a surprise to Harry to find that some of us have “had the energy” to do this, and have contributed by notifying GISS of bugs found in their code – another good reason for making the code available. You can verify that I have done so by looking for my name at http://data.giss.nasa.gov/gistemp/updates/

So I cannot comment on any possible effect of location errors on PHA.  Here are two of the location errors illustrated (green pushpin corrected, yellow pushpin GHCN-M metadata). In this case these two errors have minimal effect on Gistemp. Even though Marseille/Marignane by its very name confirms that it cannot previously have been located at the GHCN-M location, in the 4th or 5th arondissement of Marseille, the nightime luminance at both locations is clearly urban. Similarly, although it would literally require a mountain to be moved to relocate the Puy de Dôme station at the GHCN-M location, both locations are clearly rural (and for anyone still in doubt I can confirm that I have stood beside the  Puy de Dôme station, GPS in hand, and found no evidence of such a move!)MarseilleLocation



Note that this post is based on GHCN-M v3.x.x, not the recent Karl et al paper. For anyone who may want to know who is involved with both, I’ve indicated common authorship below. Karl et al uses the same Pairwise Homogenization for land temperatures, but with many additional station records. GHCNM (version 3): J. H. Lawrimore, M. J. Menne, B. E. Gleason, C. N. Williams, D. B. Wuertz, R. S. Vose, and J. Rennie (2011), An overview of the Global Historical Climatology Network monthly mean temperature data set, version 3, J. Geophys. Res., 116, D19121, doi:10.1029/2011JD016187. Possible artifacts of data biases in the recent global surface warming hiatus Thomas R. Karl, Anthony Arguez, Boyin Huang, Jay H. Lawrimore, James R. McMahon, Matthew J. Menne, Thomas C. Peterson, Russell S. Vose, Huai-Min Zhang

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Through Giant Green Goggles

Green goggles are somewhat akin to beer goggles, but the wearer sees what he or she wants to see rather than reality. A frequent synptom of the green glass wearer is a willingness to accept at face value and redistribute misinformation without a thought as to whether the “information” in question defies common sense. The “timeline” below, circulated widely, illustrates the phenomenon with misinformation at almost  every timestep. This blog post dissects it for you.

Starting from an Irish blog, name and link omitted to spare blushes: Continue reading

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Irish Alarmists Once Again

Unsurprisingly, I can report that John Gibbons, having blocked me on Twitter to avoid having his Twitter followers accidentally exposed to “heresy” (my posts Twitter exchange with John Gibbons and An explanation of the “percentigrade” error which even John Gibbons should be able to understand) has left his original nonsense stand in his posts, without comment or correction. I understand that my blocked tweets can still be seen in context by searching on Twitter for both think_or_swim and PeterONeill15, rather than either one separately. Censorship has its limitations.

Hardly surprising for an ardent advocate of suppression of views differing from his own manifestly false ‘facts’. That last was his own choice of phrase, as in

Opinions are ok but facts are sacred. Deniers flood media with manifestly false ‘facts’ to derail debate.

Where do calls for censorship fit on the spectrum of debate? Or manifestly false ‘facts’ for that matter? Is it acceptable to present your own views as if they were those of the IPCC, and drag Trócaire (or An Taisce) into that ‘monkey trap’ of your own construction? Continue reading

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An explanation of the “percentigrade” error which even John Gibbons should be able to understand

Or, taking a sledgehammer to crack a nut – apologies for overkill

but weaning Mr Gibbons from some of the tenets of his faith must be much like driving a stake through the heart of a vampire – I don’t think I have met anyone who can truthfully claim to have succeeded in either endeavour.

This is a pity, as when Mr Gibbons is not looking at the world through alarmist glasses he can write quite sensibly. He thinks for himself and parts company with many of his fellow activists and environmentalists on nuclear power, on vaccination, on homoeopathy, if my memory has not failed me, and other issues which would require a trawl through past columns and blog posts.

For anyone unaware of John Gibbons’ stubborn insistence on displaying his lack of understanding of elementary science concepts, he provides a good introduction here himself: Continue reading

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Twitter exchange with John Gibbons

In view of John’s reputation for blocking critical comments (and deleting embarrassing past blog posts) I am taking the precaution of archiving the exchange here for the benefit of any of his more curious followers who may wonder what came later should these tweets be ‘lost’.

The original links will be added later today. I’ve just posted nearly thirty times my previous total number of Tweets (1, plus a few accidental clicks which ended up as empty tweets) in the two and a half years since I was forced to join Twitter to follow Brittany Ferries and find out whether the ferry I was booked on would sail or not (it did not). I have to say that being forced to receive and wade through pretty pictures of other ferry ports without any strike linked chaos on my mobile phone, while waiting for a simple yes/no/divert to Cherbourg text tweet, did not encourage a positive attitude to Twitter. I’m taking a break for now.

Apologies for the image sequencing, duplication and omission error. Only noticed when out. Corrected now.

As anticipated, I’m now blocked by John. This may be an automated Twitter thing, in which case John is not responsible. But if he chose to block me it might have been wiser to read carefully first. My understanding is that these Tweets remain visible to his many followers even after I have been blocked – the whole point of sending them in rapid succession, and if he has actively chosen to block criticism point out his errors, which can easily be verified, this will not perhaps impress those of his followers who see it. He might have anticipated this:


Continue reading

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Temperature Adjustments In The Canadian Arctic – some supplementary information for a comment

This post extends a comment posted at https://notalotofpeopleknowthat.wordpress.com/2015/02/08/temperature-adjustments-in-the-canadian-arctic/

While Paul Homewood’s post deals with GHCN adjustments, this comment examines the influence of one of these Canadian Arctic stations, Eureka, on the Gistemp gridded output. As station coverage in the northern Canadian Arctic is sparse, this one station has considerable influence on neighbouring (and not so closely neighbouring) grid cells. Continue reading

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Our urban fox

A regular nightly visitor now. Does not seem to be the same one who followed us home. Continue reading

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