福建省沿海典型霾天气过程特征和成因分析

Characteristics and Causes of Typical Haze Weather Processes in Coastal Areas of Fujian Province

文章选取2016年3月28日-4月4日(积累型)及2016年1月18-21日(输送型)两次霾天气过程,分析福建省沿海典型霾天气过程特征和成因结果表明:积累型过程持续时间长,福建沿海受地面倒槽暖区天气形势控制,不利于污染物扩散,ρ(PM2.5)积累升高导致霾天气出现,受到较高ρ(PM2.5)和相对湿度的共同影响,能见度最低降至2 km以下,从霾生成、维持到消散具有增温、增湿、风速小的特点,大气垂直结构中出现逆温层更加不利于污染物扩散,加剧霾的严重程度。输送型霾天气过程持续时间较短,受东北冷涡和高空槽影响,低层PM2.5受东风回流影响输送至福建省沿海,导致福建省沿海自北而南出现霾天气,在污染物输送过程中,大气垂直结构中出现低层逆温不利于污染物向地面输送,会延迟霾天气出现的时间。

To analyze the characteristics and causes of typical haze weather processes in coastal cities of Fujian province,two haze weather processes were selected from March 28 to April 4,2016(cumulating type)and January 18 to 21,2016(transporting type).The results showed that the cumulating type process lasted for a long time and was controlled by the synoptic situation of warm area of ground inverted trough,which was not conducive to pollutant diffusion.The accumulation ofρ(PM2.5)leaded to the generation of haze.Visibility was affected by highρ(PM2.5)and relative humidity,the lowest visibility was less than 2 km.From the process of haze generation,maintenance to dissipation,it accorded the characteristics of warming,humidifying and low wind speed.The presence of inversion layer in the vertical structure of the atmosphere was more disadvantageous to pollutant diffusion and aggravated the severity of haze.Transporting type haze weather process lasted for a short time.Affected by northeast cold eddy and high altitude trough,PM2.5in the lower layer was transported to the coast of Fujian Province under the influence of east wind backflow,which resulted in haze weather from north to south along the coast cities of Fujian Province.In the process of pollutant transport,the occurrence of low-level inversion in the vertical structure of the atmosphere was not conducive to the transport of pollutants to the ground and would delay the occurrence of haze weather.