[cam-users] CAM 3.0 Model Release

[Jim McCaa]

Hi all,

The Community Atmosphere Model version 3.0 (CAM 3.0) was released along 
with CCSM 3.0 on Wednesday, June 23, 2004. For details, and to download 
the new model, please visit the CAM web page at:
http://www.ccsm.ucar.edu/models/atm-cam

CAM 3.0 is the latest CCSM atmosphere model and is the first major update 
since CAM 2.0. This version of the model includes updates to both the 
science and software engineering of the model.

Highlights of the software improvements include:
    * Performance improvements for all three dynamical cores in the areas of:
          o load balancing
          o interprocess communication
          o physics and dynamics decompositions
          o compiler optimizations
          o memory requirements
          o vectorization 
    * Inclusion of a single column model (SCAM).
    * New run-time controls for performance and science options.
    * Ability to output a contiguous subset of columns to the history tape 
instead of a full field. 

New science developments include:
    * Updated parameterizations for prognostic cloud water, cloud ice, 
precipitation, and cloud fraction.
    * Inclusion of a Slab Ocean Model (SOM).
    * Inclusion of ISCCP cloud simulator to simulate ISCCP statistical cloud 
diagnostics.
    * Diagnostic treatment of aerosols (sulfate, dust, sea salt, carbon, and 
volcanic).
    * Optional prognostic treatment of sulfate aerosols.
    * Improved energy conservation.
    * Modifications to longwave interaction with water vapor.
    * Updates to shortwave scheme for trace gas absorption
    * Atmosphere-land interface now supports rain and snow phases. 

Concurrent with this release of CAM are a new Scientific Description and 
User's Guide.  Please see these documents for details of the new model. 

Regards,

Jim McCaa