Large urban areas are typically subjected to excessive levels of heat and pollution. The formation of an urban-scale plume would arise from releasing heat in a stable atmosphere. The presence of wind may disrupt the pattern of the plume. This study explores the effect of wind intensity and ambient stability on the plume structure and pollution dispersion numerically. A metropolitan has been selected as the urban, and the average heat and pollution release rate is calculated based on a typical megacity. It has been found that for buoyancy ratios (the ratio between the horizontal velocity of the urban plume to wind speed) smaller than 0.5, the wind is the governing mechanism. For buoyancy ratio higher than 2, the urban heat island is governing mechanism. In stable conditions and the ratios smaller than 0.5, the urban average temperature difference reduces by about 0.125 K for a unit increase in wind speed. When the ratios are less than 0.2, there are 0.5 K temperature differences between urban and rural, and 0.072 μg/m³ averaged pollution for all stability conditions. It is also found that for ratios higher than 0.5, any increase in wind velocity does not reduce the pollution concentration significantly. For values smaller than 0.5, any increase in wind speed would result in a considerable drop in pollution concentration if the radiative effect of pollutants is ignored.

大城市地区通常遭受过高的热量和污染。城市规模羽流的形成将源于在稳定大气中释放热量。风的存在可能会破坏羽流的模式。本研究以数值方式探讨了风强度和环境稳定性对羽流结构和污染扩散的影响。选择大都市作为城市，平均热量和污染释放率是基于典型的特大城市计算的。已经发现，当浮力比（城市羽流的水平速度与风速的比值）小于 0.5 时，风是控制机制。当浮力比大于 2 时，城市热岛为治理机制。在稳定条件下，比值小于 0.5，风速每增加一单位，城市平均温差减少约0.125 K。当比值小于 0.2 时，城乡温差为 0.5 K，为 0.072 μg/m³所有稳定性条件下的平均污染。还发现，对于高于 0.5 的比率，风速的任何增加都不会显着降低污染浓度。对于小于 0.5 的值，如果忽略污染物的辐射效应，任何风速的增加都会导致污染浓度的显着下降。