复杂地形上气象条件对城市空气污染影响的数值模拟

本文通过实测资料分析和复杂地形上三维平流扩散方程模式的模拟，讨论了影响河谷城市兰州大气污染物浓度变化的气象因子。实测资料表明，冬季ＳＯ２浓度的变化与温度层结和风速差别相联系。本文建立的三维扩散模式，模拟值与实测值符合较好，并能显示出不同气象条件对污染物浓度的影响。参数敏感性试验表明：（１）Ｋｚ、风向、风速对地面浓度及其分布有很大影响。（２）Ｋｈ对地面浓度的分布也有一定的影响。（３）厚的贴地逆温和底

The Numerical Simulation for the Influence of Meteorological Condition on Urban Air Pollution over Complex Terrains

The meteorological factors which affect the air pollutants concentration of Lanzhou are discussed by analysis of observed data and a three-dimensional diffusion model over complex terrain. The analysis of observations indicates that the change of the SO2 concentration is determined by the difference of stratification and wind speed in Lanzhou. The model, which has been adjusted to suit Lanzhou, the valley city, is tested to have betteraccuracy and high stability. The numerical results agree favorably with the observation, and indicate that the model is capable of dealing with the variation of meteorological condition.The sensitivity tests demonstrate that: (1) Kh , wind speed and wind direction affect the surface concentration and its distribution (2) To some extent, Kh also determines the surface concentration and distrbution. (3) The surface concentration will increase when the groundlevel inversion is strong and thick or the inversion base is maintained at a lower-level. But the inversion base which is high has little effect on the surface concentration.