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Hi Martin,<br>
<br>
It looks like as co-authors of the DRS draft we have diverged in our
interpretations on one of these subtleties: I would not agree with the
statement "there is no assumption about temporal continuity in the
definition". I'll write you offline and see if we can straighten out
our diverging views ... then get back to the bigger list(s). <br>
<br>
Dunno if a separate message is needed on the METAFOR list??<br>
<br>
- Steve<br>
<br>
=======================<br>
<br>
Juckes, MN (Martin) wrote:
<blockquote
cite="mid:EB1E7CB92F5B35459E0B926D2A614DB60444D2A8@EXCHANGE19.fed.cclrc.ac.uk"
type="cite">
<pre wrap="">Hello,
If I've understood, the problem is that CMIP5 will have models running the same scenario, configuration etc, but different start times. I'd suggest adding a controlled vocabulary component of the form "syyyymm[dd]", with the day "dd" optional (or perhaps "frtyyyymm[dd]", for forecast_reference_time, if we want to hint at the CF equivalent -- but I think "s" for start will be clearer to most users).
There appears to be some confusion between the definition of at atomic dataset and the URL. The intention was that the atomic dataset would refer to all the data delivered matching the institute, model, scenario etc of the definition. It is not a URL and there is no assumption about temporal continuity in the definition. The rational for having an atomic dataset definition which is distinct from the URL definition is:
(1) We don't know what time periods modelling groups will provide data for (some may only provide the core request, others are expecting to provide more);
(2) URLs may want to point to subsets of the data provided if, for example, the entire data volume in an atomic dataset is too large for convenient transfer as a single file.
(3) It will me useful from an archive management perspective, to have some way of refering to collections of data which is not dependent of dataset specific information.
If defining a URL syntax for user access is now (and likely to remain) the main requirement of the document, then it should probably be rewritten with this focus,
cheers,
Martin
PS. Steve: I don't think I can post to go-essp-tech: can you forward it?
-----Original Message-----
From: <a class="moz-txt-link-abbreviated" href="mailto:go-essp-tech-bounces@ucar.edu">go-essp-tech-bounces@ucar.edu</a> on behalf of Bryan Lawrence
Sent: Tue 17/02/2009 08:10
To: Francisco J. Doblas-Reyes
Cc: Juckes, MN (Martin); <a class="moz-txt-link-abbreviated" href="mailto:go-essp-tech@ucar.edu">go-essp-tech@ucar.edu</a>; Reinhard Budich
Subject: Re: [Go-essp-tech] [metafor] the CMIP5 file uri structure
Hi Paco
Thanks for this.
I think the two times (time instant and period) do correspond
with CF as you suggest.
You've got me worried about a couple of things on the time front though,
I had thought the decadal runs would essentially be different experiments
but you're right, the delineation might not be so clean. We'll make sure
we explicity put an example or two in the doc for the decadal runs so that we're sure
we have it right.
Cheers
Bryan
On Tuesday 17 February 2009 07:33:18 Francisco J. Doblas-Reyes wrote:
</pre>
<blockquote type="cite">
<pre wrap="">Dear Bryan,
After having a look at the message below that you sent to the Metafor
community, I was wondering whether the DRS should apply to both types of
CMIP5 simulations: climate-change projections and decadal predictions.
If it applies, are the components "time instant" and "period" enough to
describe decadal forecasts that overlap in time? Are they equivalent to
the CF coordinates "forecast_reference_time" and "forecast_period"? For
the decadal forecasts in ENSEMBLES, we needed two axes to describe the
decadal forecasts in NetCDF. In GRIB we didn't have a problem because
ECMWF extensions already have to axes.
Regards,
Paco
Bryan Lawrence wrote:
</pre>
<blockquote type="cite">
<pre wrap="">hi Folks
See attached email which has the current state of play, and the attached doc.
It's not obvious to me who makes the decision that this is *THE* CMIP structure.
It yet needs linking to the proposed netcdf attributes.
Cheers,
Bryan
------------------------------------------------------------------------
Subject:
Re: uniform URL syntax to support CMIP5/AR5
From:
Bryan Lawrence <a class="moz-txt-link-rfc2396E" href="mailto:bryan.lawrence@stfc.ac.uk"><bryan.lawrence@stfc.ac.uk></a>
Date:
Tue, 10 Feb 2009 15:28:27 +0000
To:
Steve Hankin <a class="moz-txt-link-rfc2396E" href="mailto:Steven.C.Hankin@noaa.gov"><Steven.C.Hankin@noaa.gov></a>
To:
Steve Hankin <a class="moz-txt-link-rfc2396E" href="mailto:Steven.C.Hankin@noaa.gov"><Steven.C.Hankin@noaa.gov></a>
CC:
Bryan Lawrence <a class="moz-txt-link-rfc2396E" href="mailto:b.n.lawrence@rl.ac.uk"><b.n.lawrence@rl.ac.uk></a>, Michael Lautenschlager
<a class="moz-txt-link-rfc2396E" href="mailto:lautenschlager@dkrz.de"><lautenschlager@dkrz.de></a>, "V. Balaji" <a class="moz-txt-link-rfc2396E" href="mailto:V.Balaji@noaa.gov"><V.Balaji@noaa.gov></a>, Don Middleton
<a class="moz-txt-link-rfc2396E" href="mailto:don@ucar.edu"><don@ucar.edu></a>, Cinquini Luca <a class="moz-txt-link-rfc2396E" href="mailto:luca@ucar.edu"><luca@ucar.edu></a>, "Dean N. Williams"
<a class="moz-txt-link-rfc2396E" href="mailto:williams13@llnl.gov"><williams13@llnl.gov></a>, "Karl E.Taylor" <a class="moz-txt-link-rfc2396E" href="mailto:taylor13@llnl.gov"><taylor13@llnl.gov></a>,
<a class="moz-txt-link-abbreviated" href="mailto:charlotte.pascoe@rl.ac.uk">charlotte.pascoe@rl.ac.uk</a>
Hi Guys
I've made a couple of minor changes and comments.
1): this is primarily about CMIP5 ... not AR5 ... so the nomenclature should reflect that. (I've fixed that throughout I think).
2): Karl has already been working on some aspects of internal netcdf file vocabs, model short names etc, which should
match these ... we should make sure these are all congruent with the file convention. Someone needs to take responsibility for this. I suggest that Charlotte do that ... (which consists mainly of downloading Karl's input into this doc).
3): I think the hostname part of the path should be out of scope. We would expect multiple copies of atomic
datsets to be held within the federation.
4) The definition of an atomic dataset doesn't allow for the different periods within the same run being different atomic datasets (although the syntax does). I didn't fix that.
Cheers
Bryan
On Friday 06 February 2009 16:41:51 Steve Hankin wrote:
</pre>
<blockquote type="cite">
<pre wrap="">Gents,
In October 2007, when we met at GFDL for AR5/CMIP5 data management
planning, we agreed on the need for a shared URL syntax. The idea was
that the URL would uniformly reference data holdings, regardless of
where they were located. A draft of that document has been circulated
several times -- most recently at the GO-ESSP meeting in Seattle this
past September. Based upon recent discussions Martin and I have
expanded the document (just a little) to encompass the encoding of time
periods as part of the syntax. I have attached what I hope is the
semi-final (?) version of that document (v0.10) here.
I suspect we need to take two steps to proceed from this point:
1. To suggest final changes (if any) and then to mutually endorse (if
still agreed) the use of this URL as a means to reference data
through *whatever* access mechanisms (OPeNDAP, WCS, FTP, ...)
2. To make implementation plans for specific systems (and for DNS
mapping as we see appropriate)
Open for discussion ...
- Steve
</pre>
</blockquote>
<pre wrap="">
------------------------------------------------------------------------
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</pre>
</blockquote>
</blockquote>
<pre wrap=""><!---->
</pre>
</blockquote>
<br>
<pre class="moz-signature" cols="72">--
Steve Hankin, NOAA/PMEL -- <a class="moz-txt-link-abbreviated" href="mailto:Steven.C.Hankin@noaa.gov">Steven.C.Hankin@noaa.gov</a>
7600 Sand Point Way NE, Seattle, WA 98115-0070
ph. (206) 526-6080, FAX (206) 526-6744
"The only thing necessary for the triumph of evil is for good men
to do nothing." -- Edmund Burke</pre>
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