Overview, results, and conclusions for the EPRI Plume-Model Validation and Development Project: plains site. Final report

Abstract

The project is designed to provide data bases and analyses for rigorous operational and diagnostic validation of plume models. The behavior and fate of buoyant plumes emitted from tall stacks are the foci of attention. The project is field measurement oriented and is configured to generate data about plume behavior in three levels of topographic complexity. A staff of nine contractors and subcontractors designed methods, performed measurements, and conducted analyses to determine the behavior of plumes emitted from an isolated electric-generating station located on a simple plain in Illinois. The measurement effort employed 200 tracer samplers, 30 air-quality samplers, 2 aircraft, and 3 remote-sensing devices to document the plume's behavior and ground-level impact. The measurements were made during the spring and summer of 1980 and the spring of 1981. Three Gaussian models, commonly used for operational and regulatory purposes, and two numerical simulation models with first-order closure were tested against measured ground-level plume concentrations. Objective validation protocols and statistical methodologies developed for plume-model validation were employed in these tests of model performance. The model performance results clearly demonstrated important shortcomings in all the models tested, including a general inability to estimate hour-by-hour ground-level concentrations plus specific deficiencies of individual modelmore » components. Critical needs for improving model performance include better atmospheric-stability indicators and a better model framework to estimate both peak concentration values and frequency distributions of concentrations.« less