Development of vertical dispersion coefficients for deep-valley terrain. [Aerosol particle transport model]

• Main Authors: Minott, D.H., Shearer, D.L., Marker, R.S.
• Language: unknown
• Published: 2013
• Subjects: 54 ENVIRONMENTAL SCIENCES; AEROSOLS; ENVIRONMENTAL TRANSPORT; PLUMES; SURFACE AIR; AIR POLLUTION; VALLEYS; TOPOGRAPHY; DIFFUSION; GAUSSIAN PROCESSES; MATHEMATICAL MODELS; PARTICLES; AIR; COLLOIDS; DISPERSIONS; FLUIDS; GASES; MASS TRANSFER; POLLUTION; SOLS; Norway; Northern Norway
• Online Access: http://www.osti.gov/servlets/purl/5118894; https://www.osti.gov/biblio/5118894; https://doi.org/10.2172/5118894

Results are reported from studies conducted to determine reliable dispersion coefficients for use with the Gaussian plume model, that will represent a broader range of topographic conditions than was intended for the standard Pasquill-Gifford values. Total-vertical-dispersion coefficients for deep-valley terrain were developed from direct measurements of vertical dispersion made by the Norwegian Defense Research Establishment (NDRE) between 1965 and 1968, in three deep valleys, and one fjord located in northern Norway. The values developed here represent mean values within stability classes and apply to continuously-emitting sources located at ground-level. The implication is that the vertical dispersion rate in a deep valley is similar to the vertical dispersion rate found at non-valley locations having similar surface topography. While this may be true for vertical dispersion, it would not be expected to hold in the case of horizontal dispersion within a deep valley. This is because the walls of a valley act, to some degree, as physical barriers to horizontal dispersion. It is recommended, threfore, that subsequent dispersion studies in deep-valley terrain be directed towards better quantification of the effects of the valley walls on the horizontal dispersion rate.