2013年底浙西地区一次持续性灰霾天气过程分析

摘要

利用常规气象观测资料和NCEP 1°×1°再分析资料，对2013年底浙西地区一次持续性灰霾天气过程进行了分析。结果表明，该过程期间存在比较稳定的高、低空和地面环流形势，中低层湿度条件较差；低层以弱辐散和弱垂直运动为主，并且1000 hPa高度层以下浅薄逆温层的持续存在均有利于灰霾天气的维持；干冷空气前锋和主体影响期间，冷平流强度加大且低层有辐合中心和垂直上升运动中心出现，扩散条件好转是灰霾程度减弱的主要原因之一；浙西地区为盆地地形，南北高、中间低的地势不利于污染物的扩散。%By using the conventional observation data and 6 h NCEP 1°×1° reanalysis data, a persistent haze weather process in West Zhejiang during the end of 2013 was analyzed. The results indicated that the process had a relatively stable circulation of the air and the ground level with poor humidity condition at middle and low level. At low-level there was mainly a weak divergence and vertical motion, and the persistence of shallow inversion layer below 1 000 hPa was conducive to the maintenance of haze. During the dry cold air effect , the increasing cold advection intensity , low layer convergence and the vertical ascending motion were the main causes of less diffusion conditions haze. The western Zhejiang is the basin topography , and is not conducive to the spread of pollutants.