Development and Validation of a Multi-Source Plume Downwash Model
The objective of this study is to develop and validate a plume downwash model using site-specific plant operating data, meteorological data, and sulfur dioxide monitoring data at a multi-source power generating complex in Michigan. The base model selected in U.S. Environmental Protection Agency’s Gaussian-Plume Multiple Source Air Quality Algorithm (RAM). This model is modified to include plume downwash algorithms developed by Briggs and Huber. During the course of the model validation study, the accuracy and reliability of the modified base model are assessed by alternating various modeling parameters and algorithms, such as (a) Pasquill-Gifford, Brookhaven and Huber dispersion coefficients; (b) Briggs trajectory and final plume rise formulae; (c) treatment of plume rise enhanced dispersion suggested by Pasquill and Irwin; (d) treatment of plume partial inversion penetration by Briggs; etc.
The evaluation of model performance focuses on assessing the validity and accuracy of model predictions in comparison with the field measurements. Emphases are placed on the adequacy of physical representation of various segments that comprise the model for assessing its validity, and various statistical comparisons between predicted and measured concentrations for assessing its accuracy. An improved plume downwash model has been developed as a result of this study.
KeywordsDispersion Coefficient Atmospheric Dispersion Plume Height Cumulative Frequency Distribution Plume Rise
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