                RELEASE_NOTES for CMAQv4.7.1 - 13 January 2010

from Shawn Roselle Atmospheric Modeling and Analysis Division, ORD

The changes and new features of this release are:

1) Aqueous chemistry

      - Mass conservation improvements

        + Imposed 1 second minimum timestep for remainder of the cloud
lifetime

      	  after 100 "iterations" in the solver

        + Force mass balance for the last timestep in the cloud by
limiting

          oxidized amount to mass available

      - Implemented steady state assumption for OH

      - Only allow sulfur oxidation to control the aqueous chemistry
solver

        timestep (previously, reactions of OH, GLY, MGLY, and Hg for

        multipollutant model also controlled the timestep)

2) Vertical Advection

      - Added additional divergence-based constraint on advection
timestep

      - Vertical advection now represented with PPM to limit numerical
diffusion

3) Multipollutant model updates

      - Bug fix to facilitate in-line emissions option

      - Mercury

        + Dicarboxylic acid reduction mechanism applied to aqueous phase

          oxidized mercury species

        + Cl oxidation pathway based on Donohoue et al 2005 J. Phys.
Chem. A 109(34)

      - Lowered CB05 mechanism unit yields for acrolein from
1,3-Butadiene

        tracer reactions to be consistent with laboratory measurements

4) Photolysis

      - JPROC/phot_table and phot_sat options

        + Expanded lookup tables to facilitate applications across the
globe and

          extended vertical extent to 20km

        + Updated temperature adjustments for absorption cross sections
and

          quantum yields

        + Revised algorithm that processes TOMS datasets for OMI data
format

      - In-line option

        + Asymmetry factor calculation updated using values from Mie
theory

          integrated over log normal particle distribution; added
special

          treatment for large particles in asymmetry factor algorithm to
avoid

          numerical instabilities

5) Instrumented Models

      - DDM-3D

      - Sulfur Tracking

      - Primary Carbon Apportionment

------------

Known Issues:

1)  When using the inline option for biogenic emissions, only one hour
output

    timesteps are supported

2)  DDM-3D is currently only operational with the "eddy" vertical
diffusion module

    (DDM for the acm2 or acm2_inline modules will be available in the
next release)

