Mission Statement:

Implement WACCM and troposheric chemistry modules in CAM.

Goal:

To have a single model capable of being configured to run with optional
atmospheric chemistry schemes.
  
Motivation:

Currently the version of CAM that contains WACCM chemistry and physics is
maintained on a CVS branch, and similarly for the version containing
tropospheric chemistry.  Keeping code on a CVS branch up to date with
respect to the CAM development branch is alot of work which could be
avoided by improving CAM's ability to work with optional chemistry
packages.

A chemistry package is for the most part treated just like any other
physics parameterization.  Hence much of the required work to enable use of
optional chemistry packages in CAM will be accomplished by implementing the
physics interface design.  The aspect of chemistry packages which sets them
apart from other physics packages is that many chemical species are
radiatively important.  The current radiation codes in CAM are not flexible
in how they determine which mixing ratios of radiatively active species
will be used.  Adding this flexibility is the main task in this project.

Authority: 
   AMWG, Boville

Project Lead:
   Eaton

Scientific Lead: 
   None

Implementation Plan:

. Implement the CAM specific interface for the chemistry packages.  This
  part of the project is being done by collaborators from the WACCM and
  tropospheric chemistry projects.

. Design and implement a radiative constituents module whose job is to
  determine the source of a constituent and to provide the appropriate
  mixing ratios to the radiative heating calculations.

. Design and implement changes to the CAM build/run procedures to allow use
  of optional chemistry packages.

. Use all the above to merge the WACCM chemistry package onto cam_dev.
  (Done December 2004).

. Merge the tropospheric MOZART package onto cam_dev.  This will be done by
  Francis Vitt.  (by end of March 2005).

Resources:

   Eaton              2-3 months
   Lee                6   months