Effects of wind shear on pollution dispersion

摘要

Using an accurate numerical method for simulating the advection and diffusion of pollution puffs, it is demonstrated that point releases of pollution grow into a shape reflecting the vertical wind shear profile experienced by the puff within a time scale less than 4 h. For distances beyond several 10 s of kilometers from a release point, shear-related dispersion effects are probably the dominant mechanism affecting the area and magnitude of surface impacts. For assessing long- range pollutant dispersion, the common assumption that pollutants disperse as horizontally spherical "puffs" in the atmosphere is inherently inaccurate since shear-induced horizontal spreading of pollution is not a homogeneous "turbulent-like" diffusion process.