北京商务中心区大气环境的数值模拟

Numerical Simulation of Atmospheric Environment of the Central Business District in Beijing

北京商务中心区(Central Business District,CBD)位于北京市中心的东部,距离故宫博物院约4.5km,占地约4km2,最高建筑物超过300m,建成后会导致局地大气环境改变。采用基于k-ε湍流闭合的城市冠层模式对CBD建成后的大气环境进行模拟,结果表明:主导风向西北风时的大气通风能力稍优于次主导风向西南风,空气动力学粗糙度约5.3m,零平面位移约110.0m;浅色建筑外观、屋顶绿化及高叶面指数植被有助于气温的降低,可缓解夏季热岛效应;交通高峰时段,主要道路尤其是交叉路口的NOx浓度超过国家二级标准。上述研究结果对优化CBD规划设计有重要参考价值。

The Central Business District （CBD） project is located at the east part of downtown of Beijing, 4.5 km from Palace Museum, the center of Beijing City. After accomplishment of the project tall modern buildings will substitute original low-rise houses, which will lead to a series of changes in local atmospheric environment. The urban canopy layer numerical model based on lee turbulent closure method is used for simulating the atmospheric environment in CBD. The results show that urban ventilation ability under prevailing northwesterly wind is better than under southwesterly wind; aerodynamic roughness length and zero displacement are 5.3 and 110.0 m, respectively. The increase of architecture surface albedo, tree leaf area index and roof planting may cause decrease of air temperature. The air quality simulations indicate that in rush hour the traffic pollution NOx on the main roads, especially at the intersection, might be serious in future. This study could be submitted to the policy-maker and the planner for future amendments.