[cam-users] Fwd: Re: Drainage basin matrix

[Jim McCaa]

Subject: Drainage basin matrix
From: "Peter Langen" <plangen at mail.gfy.ku.dk>
Date: Wed, 28 Jan 2004 01:19:16 +0100
To: cam-users <cam-users at ucar.edu>

Hi CCM and CAM users,
I'm setting "my" CCM366 up to run with an idealized continent: Land from 0
to 60E at all latitudes, ocean elsewhere. At first I thought it would be
enough just to specify the ORO, SGH and PHIS properly in the atmospheric
initial conditions and use "arbitrary initialization" for the land model
(setting antartica = .false.). I thought that this would give me an initial
LSM dataset that I could go in and modify other fields such as SOIC2D,
SURF2D, SAND2D and (many) others. It turns out, however, that the
"real-Earth" continents are so hard-wired into the code that this procedure
gives an LSM initial dataset with the wrong number of subgrid points.

The solution was to create my own version of "olson.data" reflecting the
configuration of my continent. Then the above procedure of first using
arbitrary" and then modifying the resulting initial set manually seems to
work.

The only thing I'm not sure about now is the drainage basin matrix. I
haven't changed this (from what is given in "drainage.p5xp5.nc"). I'm
running the CCM as stand-alone and my guess is that this is only important
when running coupled to a 3D-ocean where one wants to keep track of the
freshwater budget/run-off. Is this true or does the drainage basin matrix
influence land/atmosphere/water feedbacks? If so, how?

By the way: I've heard that the CAM3 will include a SOM. Is this true? Will
it be out with the new release of CCSM in May? Will it include a sea-ice
model like the one in the CCM366 SOM?

Thanks,
Peter Langen

--
Peter Langen
Department of Geophysics, NBIfAFG
University of Copenhagen
ph: +45 3532 0552