北京2013年1月严重霾天气过程的气象成因分析  

Meteorological Characteristics Analysis of Severe Haze Weather Processes in Beijing in January 2013

作　　者：张文龙[1] 尤凤春[2] 张小玲[1] 范水勇[1] 

机构地区：[1]中国气象局北京城市气象研究所,北京100089 [2]北京市气象台,北京100089

出　　处：《气象与环境科学》2016年第2期46-54,共9页Meteorological and Environmental Sciences

基　　金："十一五"国家科技支撑重点项目"京津冀城市群高影响天气预报中的关键技术研究"(2008BAC37B01);国家自然科学基金面上项目(41175014;41075047)资助

摘　　要：利用常规观测资料、地面自动站资料及NCEP 1°×1°分析资料,结合边界层散度场的诊断分析,探讨了北京2013年1月严重霾天气过程的环流特征和气象成因。主要结论如下:1)500 h Pa为偏西气流,冷空气活动弱,无明显冷平流,对流层低层850 h Pa及其以下风速小、冷空气活动偏弱,是霾天气的显著特征。2)边界层存在逆温和大气层结稳定是霾发生的另一重要条件,逆温层不仅可出现在边界层,有时也出现在对流层低层850 h Pa附近。3)边界层存在弱辐合中心是霾形成的重要条件,特别是在区域性污染的情况下,边界层辐合可使霾因区域性污染物的输送汇聚而加重。4)偏东风对霾形成和加重具有重要作用,主要表现为风速一般较小,在边界层形成暖平流结构,易形成逆温,增加边界层相对湿度和维持边界层辐合,配合北京西部山地特殊地形,使污染物积累,最终通过增大污染物浓度及增大边界层相对湿度,造成大气水平能见度严重降低。5)1月10—14日霾天气过程主要是在边界层有弱辐合而相对湿度较低的条件下形成的,而27—31日过程主要发生在边界层相对湿度较高的条件下。Using multiple data including the NCEP 1° × 1° analysis,conventional and automatic surface weather station observations,and diagnosis of the boundary layer divergence field,an analysis was performed on the circulation and meteorological characteristics of severe haze weather processes in January 2013 in Beijing. The main results are as follows. 1） A distinct weather feature for haze is the westerly wind without significant cold advection at 500 h Pa,and the small wind speed and cold air activities near and below 850 h Pa. 2） Boundary layer temperature inversion and stable atmospheric stratification were an important condition. Temperature inversion could occur not only in the boundary layer,but sometimes appeared in the lower troposphere near 850 h Pa as well. 3） Boundary layer convergence was another important condition for the formation of haze weather,especially in the case of regional pollution.It could enhance the haze due to transportation of pollutants. 4） Low-level easterly wind played an important role in the formation and aggravation of haze. Its wind speed was generally small,and caused the warm advection and temperature inversion in boundary layer,while increasing the relative humidity and enhancing the convergence in the boundary layer. When the easterly wind blew,the western mountainous terrain of Beijing also contributed on the accumulation of pollutants and intensification of haze. 5） The haze process during January 10—14 occurred under the conditions of weak convergence and low relative humidity in the boundary layer,while the process during January 27—31 occurred under the condition of high relative humidity.

关 键 词：霾 边界层辐合 低层偏东风 逆温 相对湿度 

分 类 号：P458.3[天文地球—大气科学及气象学]