"Since the Common Land Model version 0 was frozen in
early October, we have been modifying the code to
accomodate coupling with the CCSM. We now have code
that runs in CCSM with all the CCSM requirements about
history files, restart files, etc, runs with the river
routing model, and is biogeochemical capable. The CLM v0 code
was reworked to fit into the NCAR land model infrastructure,
to fix a few recently discovered problems, and to further improve
the code engineering. The current code is compatible with both the
CLMv0 offline and CCSM drivers, and numerous zero difference tests
were done to assure consistent modification.  The following changes
were made to the base Common Land Model v0 to integrate it into CCSM:

1. The model uses the NCAR vegetation albedos and radiative transfer.
However, soil and snow albedos are as in CLMv0.

2. Snow buries vegetation vertically (as in NCAR LSM)
rather than horizontally (CLMv0)

3. The model uses the NCAR LSM stomatal conductance, to make it
compatible with CCSM biogeochemistry.

4. Soil texture (sand, clay) vary with depth, with a simple
method to constrain the hydrologic conductivity to the TOPMODEL concepts.

5. The model represents a grid cell as tiles of glacier,
lake, wetland, and vegetated. The vegetated portion of the
grid cell is further divided into up to 4 plant functional
types.

This hybrid code will provide the basis from which further
model development is made. These changes are described in
more detail in the accompanying text. Our initial testing
suggests the hybrid code is performing well compared to the
CLMv0 and NCAR LSM. Please review these changes,  comment
on them to Paul and Gordon, and perform any testing you would
like to do.

The new code, designated CLMv2 can be downloaded from:

ftp www.cgd.ucar.edu
cd pub/mvertens
get CLMLSM_hybrid.FEB_06_2001.tar

or from WWW:

www.cgd.ucar.edu/cms/mvertens/ftp/CLMLSM_hybrid.FEB_06_2000.tar

Paul and Gordon"