2014年秋季长株潭城市群一次典型霾污染天气过程的气象特征及成因分析

利用长株潭地区地面空气质量监测资料、常规地面气象资料及NCEP再分析资料和MODIS火点监测资料，结合HYSPLIT4后向轨迹模式，对2014年10月1718日长株潭地区一次严重霾天气过程的空气污染特征和成因进行综合分析。研究表明，长株潭地区此次严重霾天气污染事件的主要污染物为PM2.5，安徽南部和江西西北部地区秸秆焚烧产生的颗粒物，经高空偏东北气流引导输送到长株潭地区，是这次大范围烟霾天气的主要来源。长株潭地区西部高空槽区宽广，槽前西南气流较为强盛，地面受均压场控制，水平风速弱，为严重霾污染天气的维持提供了有利的环流条件。中低层逆温和大气底层湿度的增加，使污染物粒子不断累积；近地面连续静（小）风和风向的频繁转变，不利于污染物粒子的水平扩散；中下层弱的下沉气流、较低的混合层高度有利于污染物的垂直累积，为此次重度霾污染天气的发展、加强提供了有利的气象条件。

Meteorological Characteristics and Cause Analysis of a Typical Haze Weather Process in Chang Zhu Tan Urban Agglomeration in Fall 2014

Chang Zhu Tan region experienced a serious haze event during October 1718, 2014. The surface air quality data, conventional observation data, and NCEP reanalyzed data, as well as the MODIS fire points monitoring data were used, combining with HYSPLIT4 backward trajectory model, to investigate the pollution characteristic and cause of this haze event. The results show that the main pollutant of this heavy haze event is PM2.5. The gas pollutants releasing from crop residue burning in the south parts of Anhui province and northwest parts of Jiangxi province steered by upper northeast flow to Chang Zhu Tan region was the main source of this haze event. The upper trough over west of Chang Zhu Tan areas is broad and wide, accompanied with the powerful southwest jet before the trough and the ground uniform pressure, resulting the weak horizontal wind velocity, which provide favorable circulation conditions for the maintain of heavy haze. The inversion temperature and increasing of humidity at the middle and lower levels are important conditions for reinforcement of haze, the low wind speed and frequent change in wind direction are not conductive to the horizontal diffusion of pollutant particles, weak downdrafts and the lower mixing height are helpful to the vertical accumulation of pollutant particles, which provide the favorable weather condition for the development and enhancement of this heavy haze event.