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Community Multiscale Air Quality (CMAQ)

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The Model Development Team is pleased to announce that CMAQ version 4.4 has been delivered to CMAS for public release. You can access the model from the CMAS model download webpage Exit EPA Disclaimer.

Below is a list of updates since last year's release:

  1. Aerosols
    • added a computationally efficient coagulation routine
    • improved the efficiency of the SOA solver
    • updated ISORROPIA for stability at low relative humidity
    • added in-line documentation
    • adjusted molecular weights of inorganic species for consistency with mechanism files
      • Air Toxics
      CMAQ Model
      Science Documentation
      Release Notes v4.6
      Release Notes v4.5
      Release Notes v4.4
      Release Notes v4.3
    • changed the output variables in the aerosol diagnostic file
    • removed SOA from the definition of "dry" aerosol
    • modified SOA condensation such that it doesn't affect geometric standard deviation
    • added a new subroutine, HCOND3, to calculate condensational-growth factors
    • merged former subroutines AEROPROC and AEROSTEP into a single routine
    • removed include file AEROSTUFF.EXT (no longer needed)
    • removed modules AERO2 and AERO_DEPV1 (no longer supported)
  2. Chemistry
    • added EBI_SAPRC99 solver
    • added Rosenbrock solver
    • correction to HO2 production rate in the EBI_CB4 solver
    • removed QSSA, MEBI_CB4, and MEBI_SAPRC99 solvers (no longer supported)
  3. Process Analysis
    • corrected the Integrated Process Rate (IPR) calculations for emissions & dry deposition for aerosols
  4. Clouds
    • added the capability for "graupel" in the resolved cloud model
    • corrected the molecular weights for organic aerosols
  5. Vertical Diffusion
    • changed deposition velocity from flux form (rho*Vd) to velocity form
    • revised RDDEPV to be more general for the non-reactive species
    • initialized the INDX10 variable in AERO_EMIS.F
  6. Advection
    • bug fix in the VPPM and HPPM advection module
    • removed VBOT and HBOT (not supported in this release, may be re-released in the future)
  7. PinG and PDM
    • added capability for aerosols
    • dropped PING_MEBI_CB4 and PING_QSSA modules (no longer supported)
  8. Parallel I/O
    • incorporated speed-ups suggested by Sandia National Lab.
  9. Initial and Boundary Conditions
    • Bug fix in ICON
    • updated profiles for ICs & BCs: added species TERP
  10. Misc.
    • all no-op routines were updated for the TSTEP used in the layer dependent horizontal advection scheme
    • removed library DYNMEM (no longer required)
    • updated mechanism files molecular weights for organic aerosols and terpene
    • revised BLKSIZE parameter in HGRD_DEFN module to enhance computational performance for Linux machines with Pentium4 processors
    • corrected variable descriptions in the average concentration file

NOTE: The mechanism include files located in /project/work/rep/include/release were also updated. If you are using these files, please update your local copies to the latest version.

Atmospheric Modeling

Research & Development | National Exposure Research Laboratory

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