[Go-essp-tech] DRS corrections and extensions [SEC=UNCLASSIFIED]

Wed Jun 6 15:46:19 MDT 2012

Dear Karl,

In section 3.3 CMIP filename encoding, (page 10 of your DRS "v1-3-1-marked" document)
    there is mention of the single exception for "gridspec" files:

    In CMIP5 there is a single exception to use of the above template.
    For so-called gridspec files, which describe the grids used in a model,
    the filename should be constructed as follows:

    gridspec filename = gridspec_<modeling realm>_fx_<model>_<experiment>_r0i0p0.nc

    where <modeling realm> is now included and the variable name
    is replaced by "grid_spec".
    Note also that this is a time-independent field, so the CMIP5 table
    is "fx" and the ensemble member is set to "r0i0p0".

    Example:
      * gridspec_atmos_fx_IPSL-CM5_historical_r0i0p0.nc

My Question:
    Is there any way that this could be re-defined so that the <modeling realm>
    element is moved across to be after the <ensemble member> element?
    This just seems to make more sense to me, and keeps more of the
    file name template (from left to right) consistent with the 99.99%
    of other CMIP5 file names.  If this was adopted, the new template
    for a gridspec file would become:

    gridspec filename = gridspec_fx_<model>_<experiment>_r0i0p0_<modeling realm>.nc

    and the example would be:

      * gridspec_fx_IPSL-CM5_historical_r0i0p0_atmos.nc

The combination of the unique 'r0i0p0' (<ensemble member>) element,
    followed by the <modeling realm> element in the filename template
    makes it far easier to parse a list of thousands of file names
    to find all of those where the second field (<mip table>) is 'fx',
    or 'Amon', or 'OImon', or 'day', etc.

Thank you for your consideration of this request.

Best regards,

Lawson Hanson
-------------
    CAWCR, Climate Variability and Change group,
    Climate Change Science team,
    Bureau of Meteorology, 700 Collins Street,
    Melbourne Docklands, VIC 3008, Australia

From: go-essp-tech-bounces at ucar.edu [mailto:go-essp-tech-bounces at ucar.edu] On Behalf Of Karl Taylor
Sent: Thursday, 7 June 2012 6:58 AM
To: Kettleborough, Jamie; V. Balaji; Steve Hankin; Martin Juckes; Bryan Lawrence; Stephen Pascoe; go-essp-tech at ucar.edu
Subject: Re: [Go-essp-tech] DRS corrections and extensions

Dear all,

In February I asked for comments on my proposal to extend the DRS to  include information about spatio-temporal subsets or means.  I heard from Jamie, but no one else.  I respond to Jamie below, but I also would like your input specifically about:

1.  Is this method of describing spatio-temporal subsets acceptable?
2.  Is it worth taking this step if we don't say anything about other "processed" output?   For example how to describe "regridded" data or multi-model means.

I've attached the proposed version of the DRS, which differs from the one I sent in January only in a couple mods made in response to Jamie.

Best regards,
Karl

On 2/13/12 6:47 AM, Kettleborough, Jamie wrote:
Hello Karl,

this will be terse as I have time to review, but not to necessarily get the words right - hope I don't say anything too bad because of this.

1. section 2.3,  Not sure 'output' should be mentioned under 'product'.  I don't think 'output' ever makes it to publication level, so does not need to appear in a publication level id.  I know cmor produces it, but I think that's kind of historical isn't it, rather than necessary?  Maybe its too late for details like this?
It's true that in the end the CMIP5 output should not remain as "output", but be assigned to "output1" or "output2".  Nevertheless, I don't think there is any harm in keeping it in the DRS.

2. section 2.3 version number: to be consistent with what we really have in CMIP5 I think you need to note that v1, v2 are also present, though any *new* versions should use vYYYYMMDD.
I have modified the text to indicate that software cannot rely on the version number reflecting a date.

3. section 2.3 version:  I wonder if you need to say more (maybe not here, but if not where?) about what triggers a new version.  I think its
  a. anything that changes the content of a file already published and
  b. the addition or deletion of files from any publication data set.
  Pure 'data management' meta data changes (addition of checksums, move to new URL's) need not trigger a new version.
  Do you also need to say there is no guarantee that old versions will be kept (unless they have a DOI).
I've added some of this information now to the document.

4. section 2.4 Temporal Subsets or means: I don't understand the 'avg' example, or if I do I don't know if its right (but the point is relatively minor).  I think the example you quote as one 6 month mean field in it.  This is based on 1 day means.  I think its a little anomalous to keep the frequency as 'day' in this case.  That's not quite consistent with the definition (and I think all other uses) of frequency.  Strictly speaking frequency should be 6mon no?  (I may have misunderstood).
I think you're right.  I'm not sure why I thought this was the right way to do it.  I've changed the example,

5. section 3.5.  Does this need clarifying? I think the current wording is potentially confusing,  I think it should say something like:

'URLs referencing the data files will have a site dependent prefix (that may change due to site-specific data management tasks) followed by the directory structure.  This directory structure should (but may not) follow the recommendations of section 3.3'

I've modified the text as suggested.

6. I've noticed that the thredds catalogs also expose a thing called the file_id, e.g

<property name="file_id" value="cmip5.output1.CNRM-CERFACS.CNRM-CM5.rcp45.mon.ocean.Omon.r1i1p1.vo_Omon_CNRM-CM5_rcp45_r1i1p1_203601-204512.nc"/>

I don't know if they need a mention as being anything important (we don't use them as they don't give any version info).

We've already given 5 use cases, which I think is enough.  The DRS is used in a number of other ways.

Hope this is useful,
Yes thanks very much!
Karl

Jamie

________________________________
From: go-essp-tech-bounces at ucar.edu<mailto:go-essp-tech-bounces at ucar.edu> [mailto:go-essp-tech-bounces at ucar.edu] On Behalf Of Karl Taylor
Sent: 10 February 2012 01:32
To: V. Balaji; Steve Hankin; Martin Juckes; Bryan Lawrence; Stephen Pascoe; go-essp-tech at ucar.edu<mailto:go-essp-tech at ucar.edu>
Subject: [Go-essp-tech] DRS corrections and extensions
Dear all,

Attached is my attempt to make the DRS consistent with CMIP5 (in describing the precision of "time instants"), but primarily to extend it to a more complete treatment of spatio-temporal subsets or means.  I've also corrected a few typos.

Comments most welcome.  In particular could someone recheck sections 3.3-3.5 (which haven't been changed by me) to see if they remain consistent with CMIP5?

thanks and best regards,
Karl
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