Photochemical grid modeling of four high ozone episodes in the New England domain: CALGRID vs. UAM-IV
On behalf of a consortium of New England states and industries, model simulations have been conducted for four high ozone episodes with both the CALGRID and UAM-IV photochemical models, and the performance of these models evaluated with observed concentrations. In order to use CALGRID as an alternative model for the New England domain ozone attainment demonstration, it must be shown to perform better than the guideline model UAM-IV. The four episodes were 14--17 August 1987, 21--22 June 1988, and 7--8 and 10--11 July 1988. The CALGRID photochemical model is documented, peer reviewed and publicly available. CALGRID contains state-of-the-science improvements over UAM-IV including (1) a vertical transport and diffusion scheme that incorporates the latest boundary layer formulations and permits arbitrary level spacing, (2) a full resistance-based model for the computation of dry deposition rates (3) incorporation of both the SAPRC-90 and Carbon Bond IV chemical mechanisms, (4) a horizontal advection scheme that conserves mass exactly and has very low numerical diffusion, (5) the use of three-dimensional space- and time-varying values of meteorological parameters such as photolysis coefficients, humidity, diffusivity, pressure, and temperature, and (6) on-the-fly computation of plume rise and entrainment for more precise initial vertical distribution of plume material. The same meteorological data and boundary conditions were used for both CALGRID and UAM-IV. CALMET was used to create gridded wind, temperature, and other fields from hourly observed data provided by the Massachusetts DEP. Boundary conditions were obtained from EPA ROM simulations for the four episodes. For the July episodes, UAM-IV runs were available for the adjacent New York domain and replaced the ROM values at overlapping grid cells. The same anthropogenic emissions data were used for both models.
- Research Organization:
- Earth Tech, Concord, MA (US)
- OSTI ID:
- 20002098
- Report Number(s):
- CONF-990608-; TRN: IM200002%%98
- Resource Relation:
- Conference: Air and Waste 92nd Annual Meeting and Exhibition, St. Louis, MO (US), 06/20/1999--06/24/1999; Other Information: 1 CD-ROM. Operating Systems: Windows 3.1, '95, '98 and NT; Macintosh; and UNIX; PBD: 1999; Related Information: In: Air and Waste 92nd annual meeting and exhibition proceedings, [9500] pages.
- Country of Publication:
- United States
- Language:
- English
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