+-----------------------------------------------------------------------+
| **[Description of Change (WHAT):]{.underline}**                       |
+-----------------------------------------------------------------------+
| This package utilizes the AQM parallel slot to implement              |
| modifications to 4 jobs in the AQM forecast suite. The 4 jobs         |
| are:\<br\>\                                                           |
| (A) AQM_PREMAQ_5XPMWRF that includes the CB05 chemistry               |
| mechanism.\<br\>\                                                     |
| (B) AQM_FORECAST_5XPMWRF includes more species for aerosol            |
| chemistry.\<br\>\                                                     |
| (C) AQM_POST1_5XPMWRF output additional surface aerosol               |
| products.\<br\>\                                                      |
| (D) AQM_POST2_5XPMWRF output additional vertical profile products.    |
|                                                                       |
| The aerosol (Particulate Matter, PM) codes also require the STENEX    |
| libraries. Information on installation is provided below.             |
|                                                                       |
| Specific system improvements include:                                 |
|                                                                       |
| -   The CB05 chemical mechanism with more detailed Volatile Organic   |
|     Compound (VOC) chemistry will be implemented. The CB04 gas-phase  |
|     chemical mechanism is used in the operational version.            |
|                                                                       |
| -   The CMAQ aerosol chemistry harmonized with gas-phase mechanism    |
|     will be turned on.                                                |
|                                                                       |
| -   Source files containing point, area and mobile emissions will be  |
|     upgraded to more recent EPA National Emissions Inventory          |
|     (NEI, 2005) and then projected for the current year. These files  |
|     are also consistent with the CB05 chemical mechanism. For mobile  |
|     sources, the EPA Office of EPA Office of Transportation and Air   |
|     Quality (OTAQ ) will be used in addition to 2005 NEI v1 emission  |
|     data sets. Use of OTAQ on-road emission estimates is a departure  |
|     from the temperature dependent regression approach used in        |
|     previous years so PREMAQ scripts and codes were modified to turn  |
|     off the temperature dependencies.                                 |
|                                                                       |
| -   Additional PM species GRIB forecast will be output for model      |
|     developer and AQ focus group use only. These additional products  |
|     will not be available to the TOC but restricted to designated     |
|     scientists and state forecasters through the EMC web page         |
|     restricted access.                                                |
+-----------------------------------------------------------------------+

  -----------------------------------------------------------------------
  **[Benefit of Change (WHY):]{.underline}**

  This new implementation represent upgrades in science and scope of the
  air quality forecast capability by providing more detailed chemical
  mechanism, upgraded emission sources and the inclusion of aerosol
  chemistry. Retrospective evaluation of ozone forecasts have been shown
  to have a small improvement over the operational configuration,
  however, this implementation represents the most up to date EPA
  estimates on emission sources and more complete chemistry. This
  implementation will provide the AQ State Focus Group with more reliable
  aerosol predictions than what had been available from EMC development
  runs. The focus group provides critical feedback to NOAA model
  developers, therefore, more reliable aerosol predictions will improve
  their ability to provide useful evaluations of these products.
  -----------------------------------------------------------------------

  -----------------------------------------------------------------------
  **[User Impact Statement (WHO):]{.underline}**

  For ozone products, minimal impact is expected as the impact on ozone
  forecasts are small. An additional aerosol product, 1 and 24 hour
  averaged Particulate Matter 2.5 microns or less (PM2.5) predictions
  will be restricted to the State AQ Focus Group through a protected EMC
  web page as is done now for the CMAQ PM run on the NCO Development
  machine..
  -----------------------------------------------------------------------

  -----------------------------------------------------------------------
  **[Technical Impact Statement (TIS):]{.underline}**

  It is a new parallel implementation. There will be additional
  consumption of resources by this implementation. In development runs,
  127 tasks are used for 2 ½ CPU hours to produce the 48 hour forecasts
  compared to 65 tasks and about 1 CPU hour for operational
  configuration. The conc files size is increased to 80 GB per cycle from
  20 GB with an operational configuration.
  -----------------------------------------------------------------------

  -----------------------------------------------------------------------
  **[Risks (What could go wrong?):]{.underline}**

  The AQF system configured with aerosol chemistry and CB-IV chemistry
  mechanisms has been running and evaluated in developmental mode for
  many months. Retrospective runs have been performed with CB05 and
  aerosol chemistry. However, there can be uneven finishing timings as
  the computational intensity of the forecast model is dependent on state
  of chemical regimes.
  -----------------------------------------------------------------------

  -----------------------------------------------------------------------
  **Proposed Implementation Date and Time for Change:**

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

  ------------------ ---------------------- ------- -----------------------
  Date (MM/DD/YYYY): 04/08/2008             Time:   12Z

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