一次持续性雾霾天气过程的阶段性特征及影响因子分析  

Characteristics in Stages of a Long-lasting Fog and Haze Weather and Influence Factors Analysis

作　　者：苗爱梅[1] 李苗 王洪霞[1] 

机构地区：[1]山西省气象台,山西太原030006 [2]山西省气象服务中心,山西太原030002

出　　处：《干旱气象》2014年第6期947-953,共7页Journal of Arid Meteorology

基　　金：山西省科技攻关项目"基于GIS的极端气象灾害预警与评估集成系统"(20090311083);中国气象局关键技术集成与应用项目"山西省中尺度天气分析业务建设"(CMAGJ2012M09);中国气象局预报员专项"2012年相似环流背景下山西暴雨过程对比分析"(CMAYBY2013-009)共同资助

摘　　要：应用常规与非常规气象观测资料及PM2.5浓度监测资料,对2013年1月20~24日山西区域一次持续性雾霾天气过程进行分析。研究发现：（1）本次雾霾天气过程具有明显的阶段性特征。2013年1月20日14时至23日11时,由于相对湿度的变化导致了3次轻雾转大雾过程;23日14~20时,由于PM2.5浓度的增大经历了1次轻雾转霾的天气过程。（2）地面弱的气压场和较小的风速以及PM2.5浓度的上升和相对湿度的增大为本次持续性雾霾天气过程的形成和发展提供了有利条件。（3）边界层逆温的存在是雾霾低能见度过程形成的必要条件,边界层有逆温层而不出现雾霾天气的条件是：相对湿度〈50%,PM2.5日均值浓度〈75μg·m-3;逆温层下相对湿度的大小是区别雾和霾天气的指标。（4）相对湿度和PM2.5是决定能见度大小的关键因子,其对能见度的影响体现出明显的阶段性特征,当相对湿度〈90%时,PM2.5浓度对能见度的作用强于相对湿度,是影响能见度变化的主要因子,但随着相对湿度的增大,其对能见度的影响相对增强,当能见度降至1 km以下时,相对湿度成为影响能见度变化的主要因子。Based on the meteorological observation data and PM2. 5concentration data,a long- lasting fog and haze weather process occurred from 20 to 24 January 2013 in Shanxi Province was analyzed. The results show that：（ 1） The persistent fog and haze weather process had obvious characteristics in phases. The changes of relative humidity caused three times converting from mist to fog from 14：00 January 20 to 11： 00 January 23,and PM2. 5concentration increase caused a converting from mist to haze from 14： 00 to 20： 00 January 23.（ 2） The weak pressure filed and smaller wind speed over the ground,the rising PM2. 5concentration and increasing relative humidity were beneficial to formation and development of the persistent fog and haze weather.（ 3） The fog and haze weather was certainly companied with the temperature inversion at boundary layer,but not vice versa. And that would not appear when the relative humidity was below 50% and the daily mean PM2. 5concentration was less than 75 μg·m- 3under the temperature inversion weather conditions.The relative humidity in the inversion layer was an index to distinguish the fog and haze.（ 4） The relative humidity and PM2. 5concentration were two key factors that affect the visibility in phases. When the relative humidity was below 90%,the influence of the relative humidity on the visibility was weaker than PM2. 5concentration,and it would appear haze weather at the moment. But the influence of relative humidity on the visibility was gradually enhancing with relative humidity increase,and it was dominant when the visibility fell below 1 km.

关 键 词：持续性雾霾 阶段性特征 关键因子 

分 类 号：P426.4[天文地球—大气科学及气象学]