典型特大城市下垫面空气动力学特征参数的计算与分析研究

ESTIMATION AND ANALYSIS OF AERODYNAMIC PARAMETERS FOR A TYPICAL LARGE CITY

基于2012年12月—2013年11月上海徐家汇气象铁塔风和湍流观测资料及铁塔周边500m半径范围（平均建筑高度为39.5m）下垫面信息,分别利用温度方差方法、风速标准差方法、涡度相关法和形态学方法计算典型特大城市下垫面零平面位移和动力学粗糙度。结果表明,温度脉动方差法计算的零平面位移与建筑物高度分布存在差异,但在58-208°方向与建筑顶面积系数呈现正相关（相关系数0.73）,计算公式的经验参数、稳定度阈值和风速对计算结果影响较为显著;涡度相关方法和风速标准差方法计算的动力学粗糙度随风向分布趋势相似（相关系数0.94）,并与零平面位移呈负相关关系。形态学方法与动力学方法之间数值和随风向的变化趋势均存在差异,风温观测仪器源区和形态学方法分析区域具有显著影响。

It is an obvious problem that few studies are conducted despite accelerated urbanization process and increased land-atmosphere interaction in typical mega -cities of China. Different methods for calculating aero- dynamic parameters are evaluated for a site with tall buildings （ 〉 39.5 m mean height） in Xujiahui, Shanghai. Meteorological observations and morphometric data were both used in this study, with the former analyzed for the period from December 2012 to November 2013, and later collected for an area with a 500 m radius centered on the Xujiahui tower. The results show that zero-plane displacement （zd） calculated by the temperature variance method （TVM） has a different variation in various wind directions from building height, but has a similar trend from 58° to 208° to the plane area index （R^2 = 0. 73 ）. The TVM method is sensitive to empirical parameters, stability range, and wind speed. The standard of wind speed method （Su） and eddy correlation stress method （Es） have similar variations of roughness length for momentum （z0 ） with wind direction, and are inversely pro- portional to za input. There are obvious differences both in values and spatial patterns between the aerodynamic and morphometrie methods. The source area of measurements and the study site of morphometric methods have obvious impact on estimation and analysis.