NUMERICAL STUDY OF THE INFLUENCES ON POLLUTANT TRANSPORT DUE TO MULTIPLE CONVERGENCE ZONES IN THE SEA BREEZES OF CAPE COD AND SOUTHEASTERN MASSACHUSETTS

摘要

In New England (NE) it is common for power plants and other large emission sources to be concentrated along the coastline, where prevailing mid-latitude westerly winds can advect effluents over the ocean. Of course, mesoscale circulations, especially the sea breeze, can dominate coastal winds when the large-scale flow is weak and land-ocean thermal contrast is large. However, irregular coastlines (bays and peninsulas) and topography lead to multiple thermally driven circulations that can interact and make it difficult to estimate exposure to harmful airborne species. Therefore, a numerical investigation has been conducted to better understand the influences on pollutant transport and diffusion due to interactions between local and mesoscale sea-breezes over Cape Cod and southeast MA. The study involves a mesoscale meteorological model (the PSU/NCAR MM5v3.4), a trajectory calculator (TRAJEC) and three plume dispersion models (CALPUFF, ISC3ST, and SCIPUFF). Transport and diffusion of plumes from two power plants (elevated sources), a highway, and Otis AFB (surface sources) were calculated. A companion paper in this volume describes the dispersion modeling results (Egan et al. 2002). This paper focuses on the meteorological modeling and trajectory calculations.