Publication Date


Document Type


First Advisor

Spangler, Timothy C.

Degree Name

M.S. (Master of Science)

Legacy Department

Department of Geography


Air--Pollution--Mathematical models; Air quality--Mathematical models


Standard EPA Gaussian models drastically overestimate surface concentrations when applied to a coastal complex terrain situation under stable conditions. An examination of theoretical and experimental work concerning stable flow in complex terrain shows that blockage of flow by terrain occurs if the stratification is sufficiently strong. This stagnation in the flow is associated with increased horizontal plume dispersion and wind direction meander. Twenty-six test periods from two tracer studies conducted in coastal complex terrain during stagnant flow are examined. Three progressive modifications are made to a standard Gaussian EPA model (MPTER) incorporating the theories of flow in a terrain-blockage stagnation zone. The four models are then evaluated using the tracer-study concentration data. Analysis of the results indicate that the performance of the final modification version model (CONCEPT) is better than that of MPTER when both are applied to dispersion in a coastal complex terrain-induced stagnation zone. Modifications contained in the CONCEPT model include a split sigma modification, a virtual point-source correction, a partial reflection modification, and a partial sector-average modification.


Bibliography: pages [126]-130.


vi, 130 pages




Northern Illinois University

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