Crutem and HadCRU

I’ve been knuckling down to finishing off an article on the multiproxy study, Jones et al [1998], used in all the spaghetti diagrams. This is not robust to the Polar Urals reconstruction and a discussion of the Polar Urals site has taken on a life of its own. Many of the topics are familiar from posts earlier this year. As a spot-check of the 2005 HadCRU2 edition and the 2005 CRUTEM2 edition, I compared the gridcell series from these editions at the Polar Urals location (lat 66N, long 66E). I also compared results from the older dataset ndp020, which was either used in the Polar Urals study (or a variant edition from the same vintage) and the dataset supposedly used in MBH98 (archived in July 2004 at the Corrigendum SI at Nature). Most of the values were identical between the 2005 HadCRU and 2005 CRUTEM series, but there were 60 values which differed. The 2005 HadCRU and 2003 HadCRU series were identical where they overlapped. I’ve collated the set of differing values here. It’s a tab-separated text file and will open in Excel or R (among others). A script for doing the collation is here, but it requires prior collation of all 5 temperature datasets into R tables – which is worth doing for anyone researching specific gridcells. The time taken to set up the data in an organized way gets paid back quickly.

8 Comments

  1. TCO
    Posted Sep 24, 2005 at 12:34 PM | Permalink

    So was the inst temp series adjusted to agree better with the Urals?

  2. Steve McIntyre
    Posted Sep 24, 2005 at 5:10 PM | Permalink

    I have no idea. In business accounts when you did a lot of adjusting as here, you’d have to produce technical notes explaining it all. These are all just promulgated from on high.

  3. TCO
    Posted Sep 24, 2005 at 7:16 PM | Permalink

    Check footnote 4 of the 10K. :)

    Any suggestion on the right degree of granularity for such explanations?

    Also, what is the deal with the station data being hidden? (I mean…I had never heard that…what exactly is the status?)

  4. JerryB
    Posted Jul 10, 2006 at 11:49 AM | Permalink

    John Heckman asked Steve M:

    “You mentioned the example of the number of gridpoints versus temperature. Is that data available? It is a great example. The number of grid points probably is a proxy for urban growth and thus the UHI effect on temperature data.”

    John,

    I’m not sure what a grid point is, as compared to a grid cell, but FWIW, the number of land weather stations used by CRU has declined from over 3300 in the 1980s, to something near 1200 (or less) since 2001, based on counts in CRUTEM2.

  5. JerryB
    Posted Jul 10, 2006 at 12:43 PM | Permalink

    John,

    And please pardon my misspelling of Hekman.

  6. John Hekman
    Posted Jul 10, 2006 at 1:54 PM | Permalink

    Jerry

    Good point that the number of reporting stations has been declining. That means that the correlation referred to must be negative, and thus my point about UHI would not work. The reference I was writing about is Burger and Cubash. I haven’t read the article and don’t know what time period they were using or what results they got.

  7. JerryB
    Posted Jul 10, 2006 at 2:36 PM | Permalink

    John,

    Just let me add that there are stations that “report” their data, but that CRU does not use.

    For example, for the year 2004, data from over 1400 stations is collect in GHCN. Another approximately 1200 USA stations have presumably reported their data for 2004, and 2005, but is goes through USHCN processing, and USHCN has not published post 2003 data yet.

    In other words, the number of stations used by CRU is not indicative of the number of stations reporting data.

  8. F. Ross
    Posted Jul 25, 2009 at 9:58 PM | Permalink

    I hope this is not a total wild goose chase, but if you still need cruwlda2 try the following:

    Even though href=”http://www.cru.uea.ac.uk/advance10k/climdata.htm”> says that cruwlda2 is no longer available, if you plug in [cruwlda2] into one of the links for the other files, it still downloads.
    Example: in link ftp://ftp.cru.uea.ac.uk/projects/advance10k/glf9196b.zip for [glf916b.zip] substitute [cruwlda.zip]. I began but did not finish downloading a copy tonight 7/25/09.

    You might try the same for other files whose name and a related link is known.

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