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<<  Why do different results come from the same CCM3 code with d, http://bb.cgd.ucar.edu//viewtopic.php?t=23 >>

PostereatonPostedThu Oct 21, 2004 12:39 am MDT, http://bb.cgd.ucar.edu//viewtopic.php?p=95#95
Message: When we port CAM to a new platform (could be a different machine, or the
<br />same machine with new OS or compiler versions) one of the first validation
<br />tests we run checks that the simulation on the new platform is "within
<br />roundoff" of the simulation on a previously validated platform.  This
<br />procedure is described at
<br />http://www.ccsm.ucar.edu/models/atm-cam/port/pergro-test.html and is based
<br />on the methods described in the paper of Rosinski and Williamson (the
<br />reference for that paper is contained in the web page).  The details are
<br />given for the CAM3 build/run procedure.  This procedure can be carried out
<br />in CCM3.6.6 (the original work was done in CCM2), but some modifications
<br />are necessary.  Here are the modifications I can remember:
<br />
<br />1. A special configuration of the model is used for perturbation growth
<br />   testing.  In CAM this is a build time option which is specified by using
<br />   the !
-pergro option with configure.  In CCM-3.6.6 the option is runtime and
<br />   is specified using the pergro namelist variable in the CLM namelist.
<br />
<br />2. The output history files are set up to only contain the variable T and
<br />   PS.  CCM didn't have the 'empty_htapes' namelist variable, so there was no
<br />   easy way to start from an empty history file and just add the fields you
<br />   need using 'fincl'.  In CCM the way to do this (other than by hacking
<br />   source code) is to use the 'exclude' namelist variable to remove the
<br />   unneeded fields from the primary history file.
<br />
<br />   If you like hacking code, the easy way to eliminate all the default
<br />   fields on the primary history file is by changing the variable 'active'
<br />   from 1 to 0 at line 181 of bldfld.F.
<br />
<br />3. Postprocessing the CCM history files is probably best done by converting
<br />   them to netCDF using the ccm2nc utility,
<br />   http://www.cgd.!
ucar.edu/cms/ccm3/tools/hUtils-1.5.5.tar.gz
<br />   and then!
  obtaini
ng the cprnc utility from a CAM distribution.
<br />
<br />4. CCM3.6.6 did not have an aqua_planet option, and this is not required 
<br />   for perturburbation growth testing in that model version.
<br />
<br />I haven't tried this so there is probably some detail missing.  But this
<br />should be close.
<br />
<br />Brian

------------------------------

<<  How to change geography and ice sheets?, http://bb.cgd.ucar.edu//viewtopic.php?t=34 >>

PostercmitasPostedWed Oct 20, 2004 2:05 pm MDT, http://bb.cgd.ucar.edu//viewtopic.php?p=93#93
Message: Hello,
<br />
<br />Which are the files that store the topography and the distribution of ice sheets?
<br />May one modify these to, for example, run CCSM for an idealized continent configuration, and various ice sheet configurations?
<br />
<br />Any guidance would be appreciated.
<br />
<br />Cheers,
<br />Chris

------------------------------

<<  Correctness of output datasets, http://bb.cgd.ucar.edu//viewtopic.php?t=33 >>

PostereatonPostedThu Oct 21, 2004 2:44 pm MDT, http://bb.cgd.ucar.edu//viewtopic.php?p=96#96
Message: Doing a full climate simulation to compare against the controls is
<br />ultimately necessary.  But a good strategy for port validation includes
<br />running a perturbation growth test first, as this test requires minimal
<br />computational expense, and will reliably indicate when there is a problem
<br />with the port which needs to be fixed before running a considerably more
<br />expensive climate simulation.  The procedure for doing perturbation growth
<br />tests has been documented at
<br />
<br />http://www.ccsm.ucar.edu/models/atm-cam/port/

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