[Go-essp-tech] DRS v1.0 and CMOR2.x

[Sébastien Denvil]

Dear all,

I have seen that version v1.0 of the DRS has been released 
http://cmip-pcmdi.llnl.gov/cmip5/output_req.html?submenuheader=2#req_format 
which is very good.

Reading it, it's clear that CMOR2.x will output files to a directory 
structure (but not a filename encoding) mapping the old DRS version 
(v0.27).

My question is, what is the strong rational behind that fact? Can't 
CMOR2.x follow the version v1.0 DRS and be natively compatible with the 
ESGF data node directory structure?

The version number is apparently the reason.
<activity>/<product>/<institute>/<model>/<experiment>/<frequency>/<modeling 
realm>/<MIP table>/<ensemble member>/<version number>/<variable name>/ 
<CMOR filename>.nc

But quoting the DRS:
"Note that the version number assigned to the dataset by ESG is supposed 
to reflect the date of ESG publication, but the version will usually be 
assigned by the user so this cannot generally be guaranteed. The user 
will be instructed to provide ESG with the date that appears in the ESGF 
data node directory structure for the dataset being published. In many 
cases the directory structure will be generated some days prior to 
publication, so the date will not in fact reflect the date of 
publication, but the date that the directory structure was created."

In fine, the user will decide/provide the version number. So I think the 
user should do that via CMOR2.x.

CMOR2.x could use the current date as a version number. Or preferably, 
because cmor post-processing can last few days for a MIP_TABLE, be 
assigned to CMOR2.x via an option by the user. This would guarantee that 
all variables belonging to the same "stream" belongs to the same version 
number.

As we all hold the presses waiting for the CMOR2.5 release to continue 
the production, it could be a good timing to have CMOR2.x compatible 
with DRS v1.0. Depending on the CMIP5 data distribution system "big 
opening day" I'm willing to rewrite now what we have to be from the 
beginning in line with CMOR2.x, DRS v1.0 and publication aspect.

Regards.
Sébastien

-- 
Sébastien Denvil
IPSL, Pôle de modélisation du climat
UPMC, Case 101, 4 place Jussieu,
75252 Paris Cedex 5

Tour 45-55 2ème étage Bureau 209
Tel: 33 1 44 27 21 10
Fax: 33 1 44 27 39 02