[Go-essp-tech] Potential utility of 'priority' attribute in CMIP5 netcdf files?

[Bentley, Philip]

Hi folks,

A question that came up during recent discussions was whether or not it
would be useful to record the priority level (core/tier1/tier2) of a
CMIP5 variable as an extra metadata attribute in its corresponding
netcdf file. (I'm assuming it's not in there already - I couldn't see it
in our latest test netcdf output).

As a data producer site, I can think of use-cases where it would be
useful to issue queries that report on the core, tier1 and tier2
variables that we've generated.  And while I'm not a scientist end-user,
I can envision that they may also wish to perform similar queries, e.g.
"show me all tier2 simulations|variables produced by UKMO"

Is this capability expected to be part of the ESG/CMIP5 web portal
offering? It may well be that this will all be handled by the ESG
catalogue/metadata solution, and I'm simply not aware of it :-)

Anyway, if we did want to encode the priority as an attribute in the
individual CMP5 netcdf files it looks like this could be done by
carrying over the 'Priority' column (domain = [1,2,3]) from Karl's excel
spreadsheets into a corresponding property in the CMOR/MIP tables. From
there the CMOR library could ensure that the priority value is
trancribed into the netcdf output files.

The potential fly in the ointment is the fact that the priority
attribute appears to apply to two things: simulations *and* the
variables produced as part of those simulations. We know the simulations
are either core, tier1 or tier2. In the case of output variables it
looks (from the CMIP5 experiment docs) as though there are 'high
priority' variables and 'low priority' variables. And some of us
(guilty!) have got into the habit of calling the former 'core
variables'.

I'd be interested to hear how folks envisage this will be handled in the
ESG/CMIP5 web portal, and whether we need to encode one or both priority
values in the netcdf files (it looks like a higher level cataloging
issue to my mind)

Regards,
Phil
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