通过分析北京 32 5米气象塔风温观测资料,研究了大风天气条件下北京城市地区大气边界层特征。发现在大风天气条件下北京城市大气边界层阵风结构存在如下规律:(1 )大风条件下,对数风廓线规律可适用到 1 5 0m的高度,主要是因为城市下垫面的地面粗糙度较大,使得大风与地面粗糙元素之间的相互作用加强;(2 )阵风系数在地面附近较大,随高度呈负指数函数形式递减;(3)阵风强度随高度也呈负指数函数形式递减,但其递减率要小于阵风系数的递减率。

The characteristic of the urban boundary layer in Beijing city has been analyzed during strong wind weat her,with the observational data of the wind speed,temperature from the Beijing 325m meteoro-logical tower. We have obtained the following results about the gust structure of the urban boundary layer.(1) The vertical mean wind profiles fits the logarit hmicrule with the height up to more than 150m during strong wind weat her. That maybe is because of the large surface roughness length over urban surface, which makes a stronger interaction between the strong wind and the surface roughness elements;(2) The gust coefficient is larger in the surface,and deceases with the height by negative exponential function;(3) The gust intensity deceases with the height by the negative exponential function also,while its decrease rate is smaller than that of the gust coefficient .