Comparison of Observed and Predicted Sector-Averaged Air Concentrations for Elevated Releases of Fluorescein Particles |
| |
Authors: | D E Fields C W Miller S J Cotter |
| |
Institution: | Health and Safety Research Division, Oak Ridge National Laboratory |
| |
Abstract: | The DWNWND gaussian plume computer code was used to calculate normalized 22.5° sector-averaged dispersant concentrations at distances from 400 to 7000 meters downwind from a 56 m high release point. These results were compared to sector average values obtained in fluorescein release experiments performed at Hanford, WA between 1967 and 1973. Pasquill-Gifford (PG) and Brookhaven National Laboratory (BNL) dispersion parameterization schemes were used, and atmospheric stability classes were determined from temperature gradient (Δr/ΔZ) and wind direction standard deviation (σθ) measurements. Comparisons between calculated values and experimental results were made as functions of changes in dispersion parameterization, stability class determination method, deposition velocity v d , and gravitational fall velocity v g . Values of the correlation coefficient ranged from significant (p < 0.01) to insignificant (p > 0.05). Best agreement between comparisons was found with v g = v d = 1.8 cm/s and Pasquill-Gifford parameters based on stability classes determined using wind direction standard deviation, σθ, rather than temperature gradient, ΔT/ΔZ. The best agreement gave a Pearson’s correlation coefficient r = 0.41 (significant at p < 0.01). |
| |
Keywords: | |
|
|