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USING MM5V3 WITH ETA ANALYSES FOR AIR-QUALITY MODELING AT THE EPA
Citation:
Otte, T L. USING MM5V3 WITH ETA ANALYSES FOR AIR-QUALITY MODELING AT THE EPA. Presented at Tenth MM5 Users' Workshop, Boulder, CO, June 20-24, 2000.
Impact/Purpose:
This task objective is the development and improvement of state-of-the-science meteorology models and contributing process parameterizations for use in advanced air quality simulation model systems such as the Community Multi-scale Air Quality (CMAQ) modeling system and for other modeling studies and situations involving transport and dispersion of pollutants. Components of this work include: (a) improved meteorological and transport modeling, (b) improved meteorological modeling physics, (c) physical modeling of flows- building wakes, complex terrain, urban canyons, (d) modeling of transport and dispersion of specialized situations and (e) develop AERMOD (AMS/EPA Regulatory MODel).
Description:
Efforts have been underway since MM5v3 was released in July 1999 to set up air-quality simulations using Eta analyses as background fields. Our previous simulations used a one-way quadruple-nested set of domains with horizontal grid spacing of 108, 36, 12 and 4 km. With Eta analyses, it is anticipated that the 108-km domain (and possibly the 36-km domain) can be eliminated due to the better horizontal and vertical resolution of Eta compared to the 2.5 NCEP and ECMWF global analyses. In addition, it is anticipated that RAWINS can be eliminated from the processing pipeline since the 3-D variational analysis (3DVAR) technique used in the Eta Data Assimilation System (EDAS; Rogers et al. 1995) is widely considered to be superior to the Barnes technique used in RAWINS (Benjamin and Seaman 1985). That is, there may be little benefit to running RAWINS when the EDAS (theoretically) includes all of the observations that RAWINS could incorporate, and EDAS also ingests satellite, information. Since the operational and archived Eta domains and our 36-km simulation domain have comparable resolutions, it is hypothesized that the EDAS analyses would be appropriate to initialize our horizontal scale of interest.