[asa] Re: Successful reproduction of Eschenbach's results - and a possible explanation?

From: Iain Strachan <igd.strachan@gmail.com>
Date: Sat Dec 12 2009 - 13:17:20 EST

I just realised that what I wrote here:

>>However, I don't think there is foul play here, but instead I think there
is an error in the dataset - I believe the most logical explanation is that
the adjusted and raw data have been >>mistakenly put into the wrong
datasets, and that the REAL adjusted data should be in v2_mean.z and not
v2_mean_adj.z, which was where I extracted it.

was a bit misleading.

I am suggesting that the data for stations 0,1, and 2 which I have plotted
are the data after adjustment (as they were extracted from v2_mean_adj.z,
are in fact the Raw data, prior to adjustment. This explains the
discrepancies between the stations. The data I have plotted as "Raw"
(extracted from v2_mean.z) is in fact the data AFTER ADJUSTMENT, which
explains why they are in agreement with the other two stations.

Hence the records for stations 0 1 and 2 (raw and adjusted) were mistakenly
swapped. The more I think about it, the more this makes sense as the most
parsimonious explanation of the graphs. A genuine mistake, rather than a
clumsy conspirator.

Of course it could be a conspiracy from an AGW skeptic hacker who altered
the files and then tipped off someone .... but I won't suggest that, that
would be stirring it too much! The simplest explanation is that it was a
simple mistake.

Iain

On Sat, Dec 12, 2009 at 5:39 PM, Iain Strachan <igd.strachan@gmail.com>wrote:

> I received yesterday an email out of the blue from Robert Wittig, who had
> read of my unsuccessful attempts to reproduce Eschenbach's results while
> browsing the ASA archive.
>
> He showed me how to reproduce them; apparently the "adjustments" I had
> downoaded were the GISS adjustments and not the GCHN adjustments. He
> enclosed an excel spreadsheet, where he had reproduced the graphs.
>
> I have always gone into this with an open mind and desire to get honestly
> at the truth. It appears Eschenbach was not fabricating his results (though
> his interpretation of those results is of course up for debate). I have
> independently reproduced Eschenbach's results (and Wittig's) by downloading
> the raw data, and plotting them out using Matlab. The following five links
> give the plots I obtained:
>
> http://picasaweb.google.com/IGD.Strachan/NOAADarwin#5414394772197509010
>
>
> shows the "Raw" data for all five stations - and as can be seen they are
> all in close agreement.
>
> http://picasaweb.google.com/IGD.Strachan/NOAADarwin#5414394772652507794
>
>
> shows the "Adjusted" data - adjustments only exist for stations 0 1 and 2.
> It is curious and does to me require some explanation as to why these are
> all quite different, whereas in the raw data they are in agreement.
>
> http://picasaweb.google.com/IGD.Strachan/NOAADarwin#5414394774309127298
>
> This is the most controversial one and appears also in Eschenbach's
> article. It shows the raw and adjusted data for Station zero (of "smoking
> gun" fame). As can be seen there are step adjustments in 1979,1962,1951 and
> 1930. The first two of these appear to be exactly 2/3rds of a degree ( the
> data-tips show 0.6667 and 1.3333). The other two adjustments are of a
> similar order. This looks suspicious because there appears to be a rising
> trend from 1940 onwards in the adjusted data, in line with the adjustments.
> This is what Eschenbach calls a clumsy effort to create a trend where none
> was present.
>
> From the above link you can navigate, via arrows to the other to pictures
> in the album which show the similar traces from stations 1 and 2.
>
> I obtained the datasets from the following website (provided in a link in
> the comments to Eschenbach's article, and which Robert Wittig has helpfully
> provided for me:
>
> http://www1.ncdc.noaa.gov/pub/data/ghcn/v2/
>
> The relevant datasets to download are v2.mean.z, v2.mean_adj.z,
> v2.temperature.inc, and v2.temperature.readme files
>
> The compressed .Z files can be unpacked using something like WinZip (I used
> PowerArchiver). The readme file shows how to interpret the lines of data,
> and the v2.temperature.inc file gives the station code to search for.
>
> Robert used an Access database to extract the data for Darwin; I wrote a
> Matlab script to parse the data, and hence extracted it independently of
> him. I then produced the plots using Matlab. In the datasets, the
> temperature value of -9999 is used to indicate missing data. I computed the
> yearly averages (each line has 12 readings) by averaging the values that
> were not marked -9999.
>
> My explanation:
>
> Clearly this cries out for explanation. Eschenbach suggests that this was
> a crude attempt to massage the data to manufacture a trend.
>
> However, I don't think there is foul play here, but instead I think there
> is an error in the dataset - I believe the most logical explanation is that
> the adjusted and raw data have been mistakenly put into the wrong datasets,
> and that the REAL adjusted data should be in v2_mean.z and not
> v2_mean_adj.z, which was where I extracted it.
>
> This means that the true raw data (which is in the "adjusted" set) shows
> disagreements between the stations for 0 1 and 2 which could be down to
> anything (siting, covering on the instrument etc), which after correction
> agree with all the rest of them.
>
> This would make sense, because the original dataset I pulled off the GISS
> website stated:
>
> "Raw GHCN data + USHCN corrections" (5 stations)
>
> so I'm guessing that the USHCN corrections are the ones we see in
> Eschenbach's diagram, and these are NOT the "inhomogeneity" adjustments.
>
> Note that the "Raw GHCN data + USHCN corrections" graph ( see mine at:
> http://picasaweb.google.com/IGD.Strachan/Darwin#5413595233568220978 )
> agrees with the "Raw" data from the NOAA website.
>
> Hence, I suggest that the data for stations 0 1 and 2 raw and adjusted on
> the NOAA website have been mistakenly put in the wrong archives. This then
> reverses the conclusion that Eschenbach drew. It would appear to me that
> before the adjustments, the discrepancies between the stations showed a
> trend that wasn't real, and the adjustments removed the false rising trend
> for this station.
>
> Now... if I'm totally honest, I don't know if my explanation is the right
> one. The alternative one is that the data raw and adjusted are as they are,
> and that it does look suspiciously like the data has been massaged to make a
> trend. I think the experts on the list had better judge for themselves. I
> am quite suspicious of those figures 0.6667 and 1.3333, two successive
> adjustments of exactly 2/3 of a degree. That didn't look like it was
> computed by a machine because it wouldn't be so close to a simple ratio (not
> twice over).
>
> I'm awaiting the comments from Rich Blinne with great interest.
>
> Many thanks to Robert Wittig (cc'd in on this) for providing me the
> relevant explanation.
>
> Regards,
> Iain
>
>
>
>
>
>
>
>
>
>
> --
> -----------
> Non timeo sed caveo
>
>

-- 
-----------
Non timeo sed caveo
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Received on Sat Dec 12 13:17:54 2009

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