厦门市大气能见度变化规律及影响因子分析

Atmospheric visibility trends and analysis of the influencing factors over Xiamen city

以厦门市为研究对象,基于2014—2016年监测数据,分析大气能见度变化规律,探究大气污染物(PM_(10)、PM_(2. 5)、SO_2、NO_2、CO、O_3)浓度及气象因子(风速WS、大气温度T、露点温度DPT、最低云层高度CCH、海平面压强SLP、相对湿度RH)对大气能见度的影响。研究表明:厦门市年均大气能见度为8. 97 km,年度最高值出现在夏季,最低值出现在春季;日最高值出现在中午,最低值出现在凌晨;除O_3外大气能见度与大气污染物浓度均呈负相关,与T、WS和CCH呈正相关,而与RH,DPT及SLP呈负相关;通过K均值聚类分析,综合得出厦门市7组典型天气的大气能见度及相关气象指标与其它污染物浓度均值;利用消光系数(βext)与大气污染物浓度,构建了回归模型(β_(ext)=0. 007PM_(2.5)+0. 143,R^2=0. 500;β_(ext)=0. 005PM_(10)+0. 119,R^2=0. 393;β_(ext)=0. 011SO_2+0. 249,R^2=0. 168;β_(ext)=0. 007NO_2+0. 155,R^2=0. 313),能代表β_(ext)与各大气污染物的关系。

Taking Xiamen as the subject,based on the monitoring data during 2014-2016,the atmospheric visibility trends were analysed and the impacts of air pollutants ( PM10,PM2.5,SO2,NO2,CO and O3) and meteorological factors (wind speed,temperature,dew point temperature,minimum cloud height,sea level pressure,relative humidity,and relative humidity ) on atmospheric visibility were studied.The results show that the annual average atmospheric visibility is 8.97 km over Xiamen.The annual highest value occurs in summer,and the lowest in spring.The daily highest value occurs at noon and the lowest at midnight.The atmospheric visibility is negatively correlated with the concentration of air pollutant except O3,and positively correlated with T,WS and CCH,but negatively with RH,DPT and SLP .Through the K-means clustering analysis,we obtained 7 classes of the typical weather in Xiamen including the data of average value about atmospheric visibility,related meteorological indexes and the concentration of other pollutants.The regression model (βext=0.007PM2.5+0.143,R^2=0.500;βext=0.005PM10+0.119,R^2=0.393;βext=0.011SO2+0.249,R^2=0.168;βext=0.007NO2+0.155,R^2=0.313) was constructed by using the extinction coefficient (βext ) and the concentration of air pollutants,which could represent the relationship between β ext and the concentrations of pollutants.