衡阳市冬季PM2.5外来输送特征及潜在源分析

ANALYSIS OF CHARACTERISTICS AND POTENTIAL SOURCES OF PM2.5 EXTERNAL TRANSPORTATION IN HENGYANG IN WINTER

利用HYSPLIT模型的后向轨迹模式,结合GDAS气象数据、衡阳市PM2.5质量浓度数据,分析了衡阳市2015—2017年冬季外来气团后向轨迹分布特征,并运用后向轨迹模式中的聚类分析法、潜在源分析法(PSCF)、浓度权重分析法(CWT),分析了衡阳市冬季PM2.5外来输送通道及潜在源分布情况。结果表明:衡阳市冬季外来气团后向轨迹主要来自偏北方向,移动速度较慢,100 m高度的PM2.5外来输送路径较集中,以近距离输送为主;500 m高度的输送路径较分散且更长,长距离输送的影响增大。聚类分析显示,来自东北方向的聚类轨迹出现频率最高,该类轨迹移动方向是PM2.5外来输送的主要通道方向。潜在源分析显示,衡阳市冬季PM2.5外来输送以区域输送为主,对浓度影响较大,湘东、湘南、赣西、湘赣交界处、桂东北、豫南地区为PM2.5外来输送的主要潜在源区,湘南、湘东北、赣西地区是高浓度外来输送潜在源区。

Backward trajectory pattern of HYSPLIT model was used along with GDAS meteorological data and PM 2.5 concentration data of Hengyang,to analyze the distribution characteristics of the backward trajectory of the external air mass in winter in Hengyang from 2015 to 2017.In addition,the distribution of PM 2.5 external transport channels and potential sources in Hengyang were analyzed via cluster analysis method,PSCF method and CWT method.The results showed that the backward trajectory of the external air mass of winter in Hengyang mainly came from the northern direction,and its movement speed was relatively slow.The external transport path of PM 2.5 at the height of 100 m was relatively concentrated,mainly at the height of short-range transport.The external transport path at the height of 500 m was relatively scattered and longer,and the influence of long-distance transport was increased.The cluster analysis showed that the clustering trajectory from the northeast direction had the highest frequency,and the moving direction of this kind of trajectory was the main channel direction of PM 2.5 external transportation;the potential source analysis showed that PM 2.5 external transport in Hengyang in winter was mainly regional transport,which had great impact on concentration.The eastern and southern Hunan,western Jiangxi,the border area between Hunan and Jiangxi,northeastern Guangxi and southern Henan were the main potential source areas for PM 2.5 external transport in Hengyang;the southeastern Hunan,northeastern Hunan and western Yunnan were potential sources of high concentration external transport area.