Two‐dimensional transport of dust from an infinite line source at ground level: non‐zero roughness height

The previous study (Eltayeb & Hassan 1992) of the 2‐D diffusion equation of dust over a rough ground surface, which acts as a dust source of variable strength, under the influence of horizontal wind and gravitational attraction, is here extended to all finite values of the roughness height Z_o. An analytic expression is obtained for the concentration of dust for a general strength of the source. The result reduces to the previously known solutions as special cases. The expression for the concentration has been evaluated for some representative examples of the source strength g(X). It is found that the concentration decreases with roughness height at any fixed point above ground level.