Subject: Re: Question about SEP1.T42.0198
From: Erik Kluzek (erik@ucar.edu)
Date: Wed May 16 2001 - 10:32:41 MDT
On Wed, 16 May 2001, In-Sun Song wrote:
> Dear CCM users
>
> Is SEP1.T42.0198, which is distributed with CCM3.6.6, climatological
> initial data
> for september 1?
>
> In NCAR CCM website, I could find that SEP1.T42.0198 is made through
> 5-year spin up process. Could you inform me of the initial condition for
> the 5-year spin up process?
>
> Looking forward to your answers.....
>
Valid question, here's the answer.. (from the "ccm/doc/DatasetLog" file in the
source distribution by the way)
File: SEP1.T42.0198.nc
File type: 64 bit CCM history tape netCDF
Resolution: T42
What is it: 18 level, initial conditions file for
Sep/1st conditions. This was run from a
5 year spin-up run with standalone CCM and LSM. The case name
was /ERIK/csm/cls3331a, which was run from straight CCM3.3.31
code. LSM was started from arbitrary initial conditions,
standard namelist values as per sld012a were used with
orbital parameters set to 1950 conditions and solar constant
to 1367. W/m2
NCDATA = 'SEP1.T42.0697.nc'
BNDTVS = 'STR-sst.T42.0596.nc'
BNDTVO = 'ozn.0596.r8.nc'
IYEAR_AD = 1950
SCON = 1.367e6
So the IC file SEP1.T42.0697.nc was used for a 5-year simulation that created
the SEP1.T42.0198.nc IC file. I beleive that SEP1.T42.0697.nc came from the
SEP1.T42.0596 dataset just converted to NetCDF. To find the history of the
SEP1.T42.0596 dataset look at the web-page....
http://www.cgd.ucar.edu/cms/ccm3/initial/SEP1.T42.0596.README
(available as a link under http://www.cgd.ucar.edu/cms/ccm3/initial/)
So SEP1.T42.0596 was converted to SEP1.T42.0697.nc, and then used for a
simulation to create SEP1.T42.0198.nc. The original SEP1.T42.0596 was
from a simulation from another IC file which was probably created from
an earlier simulation and so on probably for several generations.
Since, the model quickly diverges from it's initial conditions, I'm not
sure how relevent understanding this history is though. The main lasting signal
is how the land-model is spun up -- since it takes longer for land-processes to
equilibrate.
Erik Kluzek, (CGD at NCAR)
National Center for Atmospheric Research
Boulder CO, (off) (303)497-1326 (fax) (303)497-1324
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