天津市滨海新区持续性重度雾霾成因分析

Causes of a Continuous and Severe Fog and Haze in Binhai New Area of Tianjin

2015年12月20—26日滨海新区出现持续性重度雾霾天气,空气质量指数AQI持续5 d大于200。利用大气观测、探测及污染物探测资料、NCEP再分析资料等,分析此次重度雾霾成因。结果表明,持续的纬向性环流及地面弱气压场,使逆温层建立;近地面切变线使污染物、水汽汇聚结合形成持续雾霾。逆温层接地后,当主要污染物PM2.5浓度>350μg/m^3时,相对湿度即使小到45%,也会出现能见度<2 km的重度霾;当PM_(2.5)浓度>300μg/m^3、相对湿度>90%时,会出现能见度<0.1 km的严重雾霾。逆温层不接地,当PM_(2.5)浓度<65μg/m^3时,即使相对湿度>90%,能见度也会>6 km,不能形成雾霾。因此逆温层形成后接地和污染物浓度是滨海新区持续重度雾霾产生的关键条件。

There were persistent heavy fog and haze weather in December 20th -26th,2015 inBinhai New Area of Tianjin,The air mass index AQI is greater than 200 for 5 consecutive days. Inthis paper,we use atmospheric observations,detection and pollutant detection data,NCEPreanalysis data,etc. to Analyze the cause of heavy fog and haze .The results show that,thecontinuous zonal circulation and weak pressure field on the ground help to establish the inversionlayer, shear line near the ground help to combine pollutants and water vapor convergence to formacontinuous fog and haze. After the inversion layer is grounded,When the main pollutant PM2.5concentration is greater than 350 μg/m3,even though Relative humidity is as small as 45%, Therewill also be severe haze and visibility will be less than 2 km.When PM2.5 concentration is greaterthan 300 μg/m3, and When the Relative humidity greater than 90%,there will be serious fog andhaze,and visibility is less than 0.1km. When the inversion layer is not grounded and the PM2.5 oncentration is less than 65 g/m,the visibility will be greater than 6km and and Can not form fog andhaze Even if the relative humidity is greater than 90%. Therefore,after the establishment andgrounding of the inversion layer and the concentration of pollutants are key conditions for theformation of severe fog and haze formation in Binhai New Area.