Here are some climate model coding standards that I’ve collected over the last few months:

It’s encouraging that most modelling centres have developed detailed coding standards, but it’s a shame that most of them had to roll their own. The PRISM project is an exception – as many of the modelling labs across Europe were members of the PRISM project, some of these labs now use the PRISM coding rules.

Two followup tasks I hope to get to soon – (1) analyze how much these different standards overlap/differ, and (2) measure how much the model codes adhere to the standards.

16/11/2010 Update: The UK Met Office standard was an old version that was never publically released, so I’ve removed the link, at the request of the UKMO. I’ll post a newer version if I can sort out the permissions. I’ve added MPI-M’s ICON standards to the list.


  1. The PRISM standard is pretty good, apart from mandating CVS.

  2. Pingback: Coding Standards Finally Appear « Models Methods Software

  3. Dan Hughes started down this trail several years ago; as a “friendly” maybe you’ll find this pursuit more fruitful.

  4. Josh: Dan doesn’t seem to have much to show so far if he’s been at this for several years. The title he used for the post you link to is very telling: “coding standards finally appear”. Obviously, they were very cleverly hidden before, because nobody (least of all Dan) would ever think of typing “climate model coding standards” into Google.

  5. How does The Google work when you’ve searching for NASA/GISS ModelE information in 2006 for documents made available in 2010?

  6. The NASA one is dated 2010, but the others are much older:
    – NCAR’s is dated June 2001
    – IPSL’s is dated 2010, but is version 2 of a document that’s been around for at least 5 years (I can’t find a date for version 1, but here’s one of its predecessors:…/coding_rules_OPA9.pdf
    – the PRISM document is dated 2002
    – the UK Met Office document is dated 1998
    – GFDL’s is dated 2002.

    It’s a pity your google-fu is so weak.

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  8. Modelers at Japan Meteorological Agency (including Meteorological Research Institute and Numerical Predition Division) made this document in 2002.

    Chiashi MUROI, Eizi TOYODA, Hiromasa YOSHIMURA, Masahiro HOSAKA and Masato SUGI, 2002: Standard coding rule. Tenki (Bull. Meteorol. Soc. Japan), Vol. 49, 91 – 95 (in Japanese).

    A follow-up dated 1 Dec. 2005 is here (in Japanese).

  9. Some questions that would be interesting to answer:

    (1) case-sensitivity in Fortran. Which standards require it, now that color syntax-highlighting is ubiquitous. (e.g. PRISM expects uppercase keywords)
    (2) doxygen / PROTEX, etc. documentation in comments. Any standardization on doxygen?

    Interoperability between languages: PRISM uses cfortran, which predates iso_c_binding in the Fortran 2003 standards.

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