Jonathan Gregory writes:
> Dear John
>
>> Im not sure if we ever converged on how to write ensemble files.
> No, we didn't. If I remember correctly, we couldn't agree on the relationship
> between attributes and coordinates, and that was a sticking-point. I thought
> that we ought to allow multivalued auxiliary coord variables for ensemble
> axes, corresponding to attributes that might be used to describe a single
> model. I would give these standard_names to identify them. Paco started the
> discussion, and in the end he made his own decisions for what to do for the
> ENSEMBLES project (because CF had not concluded), so he might comment on it.
http://ensembles.ecmwf.int/thredds/ensembles/stream2/seasonal/atmospheric/catalog.html
has examples of how Paco has it set up.
(esp see the "mother of all aggregations" :-).
It requires the ensemble to share the same space and time
discretization.
>
>> Particularly, how does software recognize the ensemble dimension?
> We didn't agree. But at the end of the discussion, Steve also suggested that
> it could be identified by an axis attribute, just as you have. I like that
> idea too. But it could also be given a standard name, like other coordinate
> variables e.g. ensemble_member_identifier. I suppose the values of this
> coord var might be either numeric or strings, though it your example it is
> integer. I haven't looked at the trac ticket to see if we discussed these
> points before.
>
>> Perhaps we should add :axis = "Ensemble" to the model coordinate variable?
> I'd suggest lower case, like most CF keywords. The other axis attributes are
> all single letters (X Y Z T) but I don't think it would be a problem to use
> a word.
>
> Best wishes
>
> Jonathan
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--
V. Balaji Office: +1-609-452-6516
Head, Modeling Systems Group, GFDL Home: +1-212-253-6662
Princeton University Email: v.balaji at noaa.gov
Received on Tue Mar 16 2010 - 13:31:27 GMT
