Study on Atmospheric Diffusion in a Street-Canyon by Air Tracer Dispersion Experiment (III)

On the Relation between Parameter K of SRI Street-Canyon Model and Roof-Top Wind Velocity

Abstract

In order to predict the concentration at the leeward side of the canyon (C_L), therelation between parameter K in the SRI street canyon model and the rooftop wind velocity was investigated by using the field data of air tracer dispersion experiment.
The major conclusions are as follows:(1) When the rooftop wind direction was perpendicular to the road, parameter K increased with increasing rooftop wind velocity.
(2) The relation between K and rooftop wind velocity (U_H) was expressed well by the following equation,
K=α·[(U_H+0.5) (x²+z²) ^0.5+2]/(δ_w·L) where a is constant, x and z are the horizontal and the vertical distances of the receptor from the line source, respectively, aw is the standard deviation of the vertical wind velocity and L is the width of the canyon.