[Go-essp-tech] RIP clarification

[charlotte.pascoe at stfc.ac.uk]

Hi Karl,

If we can agree to handle r.i.p. as Bryan suggests then we don't have to make any changes to the questionnaire  
- a Very Good Thing
 
> The way the questionnaire originally did this was to have the mods 
> defined (once), and then - per ensemble member - assign r.i.p against 
> those mods. I hope that doing that achieves the compromise necessary.

Charlotte
--- --- --- --- --- ---
Charlotte Pascoe 
+44 (0)1235 445869
BADC - CEDA - RAL - STFC
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-----Original Message-----
From: Bryan Lawrence [mailto:bryan.lawrence at stfc.ac.uk] 
Sent: 02 February 2011 06:19
To: Karl Taylor
Cc: Pascoe, Charlotte (STFC,RAL,SSTD); go-essp-tech at ucar.edu; g.m.devine at reading.ac.uk; metafor at lists.enes.org
Subject: Re: RIP clarification

Hi Charlotte

Yes, I agree, what's intended may not occur.

The way the questionnaire originally did this was to have the mods 
defined (once), and then - per ensemble member - assign r.i.p against 
those mods. I hope that doing that achieves the compromise necessary.

Cheers
Bryan

> Hi Charlotte,
> 
> Congratulations! you managed to crack the intended use of "rip" in
> spite of what I thought was  a scheme so complicated, that no mere
> mortal could be expected to decipher it.
> 
> That being said, I think we should probably expect others (with
> lesser proclivity to meticulousness) to fail in attempting to follow
> the recommendations.  In particular, we may not be able to count on
> the "p" and "i" values being consistent across all simulations by a
> single model.   If that were the case, would it completely disrupt
> your plans?
> 
> One approach would be as follows:
> The first time that someone records the information for an experiment
> (i.e., the first member of the "rip" ensemble), they would be asked
> to document the model and all the experimental conditions.  Then
> when subsequent members were entered, they should only have to
> reference the first member and say how the model physics (in some
> cases when p differs) or the experiment conditions (initial
> conditions when "i" differs and in some cases "forcing" when "p"
> differs).  In the case of a different value of "r", typically the
> "spawning" point from the run will differ from one member of the
> ensemble to another.  [Note, however, that for the TAMIP project,
> this identifies a different start time for the forecast within the
> season.]
> 
> Sorry it's so difficult.
> 
> Best regards,
> Karl
> 
> On 2/1/11 6:09 AM, charlotte.pascoe at stfc.ac.uk wrote:
> > Hi Karl and Bryan,
> > 
> > It is important to know how the r<N>i<M>p<L> indices are to be
> > implemented in CMIP5 so that we can be sure that information about
> > them is captured correctly by the questionnaire. Here is my
> > understanding, please correct me if I’m wrong!
> > 
> > The scope of the p<L> and i<M> indices are model wide – these
> > indices must mean the same thing across all simulations for a
> > particular model.
> > 
> > The scope of the r<N> indices are experiment wide – the r index is
> > not required to mean the same thing across all simulations for a
> > particular model, so the r indices can be reused by different
> > experiments.
> > 
> > Here is an example to show what this would mean in practice.
> > 
> > If the meaning of the r<N> indices were confined to an experiment
> > 
> > then if you had used r1, r2, and r3 to label the members of an amip
> > ensemble:
> > 
> > tas_day_HADCM3_amip_r1i1p1_197901-200901.nc
> > 
> > tas_day_HADCM3_amip_r2i1p1_197901-200901.nc
> > 
> > tas_day_HADCM3_amip_r3i1p1_197901-200901.nc
> > 
> > you could use r1,r2 and r3 again to label the members of a
> > different experiment, say decadal2000:
> > 
> > tas_day_HADCM3_decadal2000_r1i2p1_200001-201001.nc
> > 
> > tas_day_HADCM3_decadal2000_r2i2p1_200001-201001.nc
> > 
> > tas_day_HADCM3_decadal2000_r3i2p1_200001-201001.nc
> > 
> > rather than having to begin labelling from a new r index, say r4:
> > 
> > tas_day_HADCM3_decadal2000_r4i2p1_200001-201001.nc
> > 
> > Where
> > 
> > p<L> - identify perturbations in physics (from the same base model)
> > 
> > i<M> - identify perturbations in initialisation method
> > 
> > r<N> - identify ensemble members which differ in other
> > characteristics.
> > 
> > Please shout if my interpretation is wrong!
> > 
> > Kind regards,
> > 
> > *Charlotte*
> > 
> > ----------------------------------------------------------
> > 
> > Dr Charlotte Pascoe
> > 
> > NCAS British Atmospheric Data Centre
> > 
> > STFC Rutherford Appleton Laboratory
> > 
> > Phone +44 1235 445869; Fax ...5848
> > 
> > e-mailcharlotte.pascoe at stfc.ac.uk <mailto:c.l.pascoe at rl.ac.uk>
> > 
> > ----------------------------------------------------------

--
Bryan Lawrence
Director of Environmental Archival and Associated Research
(NCAS/British Atmospheric Data Centre and NCEO/NERC NEODC)
STFC, Rutherford Appleton Laboratory
Phone +44 1235 445012; Fax ... 5848; 
Web: home.badc.rl.ac.uk/lawrence
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