Evaluation of an Aerosol Model: Responses to Meteorology and Emission Scenarios

The Fraser Valley is a complex topographic coastal environment which episodically experiences visibility degradation (and elevated aerosol concentrations) (Pryor et al., 1997). To examine concentrations and speciation of secondary inorganic aerosols and ozone in the transition between an oxidant event and period of elevated aerosol concentrations, numerical simulations were performed using a modified version of the ACDEP (Atmospheric Chemistry and Deposition) model. ACDEP is a lagrangian model which contains detailed and fully coupled gas-aerosol phase chemistry (Hertel et al., 1995). The modeling period is August 5–8, 1993, and the modeling domain is shown in Figure 1. Results calculated for two receptor sites are shown herein (locations specified in Figure 1). PIME is located in the western reaches of the valley directly east of the Vancouver metropolitan area, and CHIL is located in a region of mixed agricultural land, approximately 80 km from the Vancouver urban core. The modified ACDEP model was applied at a horizontal resolution of 5 km and with 10 layers in the vertical, increasing logarithmically from 2 m to 2 km. The meteorological parameterizations within ACDEP have been extended such that stability parameters and mixed layer depth are calculated using routinely available meteorological data.