【摘要】 利用2015年1月15—27日在苏州东山气象观测站系留气艇观测数据以及细颗粒物浓度观测资料,对东山大气边界层结构特征及其对污染物垂直结构分布的影响进行分析研究。结果表明:苏州东山地区冬季空气污染过程的边界层结构演变比较典型,夜间稳定边界层高度约为200 m,白天最大边界层高度可达1 000m。边界层内污染物垂直结构分布易受边界层高度的影响,较低的大气边界层高度可使细颗粒物在近地层持续累积;反之,边界层高度较高,湍流发展旺盛,颗粒物垂直分布均匀。夜间大气边界层稳定,逆温结构多发,导致近地面出现细颗粒物堆积。风的垂直结构对细颗粒物空间分布也存在显著影响,在风速较小的低空层细颗粒分布较多,而风速较大的中高层的分布较少。更多还原

【Abstract】 During January 15—27, 2015, a sounding experiment in atmospheric boundary layer over Dongshan, Suzhou was performed. Structural characteristics of atmospheric boundary layer conditions and the impacts brought by boundary layer structure on the vertical distribution of pollutants in Dongshan were studied. The results show that the evolution of boundary layer structure over Dongshan in the process of air pollution is typical. Stable boundary layer height was 200 meters at night, and the maximum boundary layer height during the day was 1 000 meters. Pollutant concentration in the boundary layer was easily affected by its height, and low boundary layer height made fine particulates accumulate in the surface layer; on the contrary, when the boundary layer height was high, turbulence developed vigorously, and fine particulates were distributed evenly in the vertical direction. In addition, due to the stable boundary layer with inversion structure at night, pollutants were prone to gather near the ground. The vertical structure of the wind distribution also had a significant effect on the spatial distribution of fine particulates. The distribution of fine particles is more in the low-velocity layer with smaller wind speed but less in the middle and high layers with larger wind speed.更多还原