鲁中地区2015-2016年冬春季两次持续性霾天气过程的综合对比分析

Comparative Analysis of Two Persistent Hazy Processes in Central Shandong Province in Winter and Spring of 2015-2016

为探讨鲁中地区20152016年冬春季持续性霾过程的演变特征和影响因素,利用气象资料、环境监测数据,结合CALIPSO卫星资料及HYSPLIT后向轨迹模式,对分别发生在冬春季的两个个例的气象条件、气溶胶粒子分布和污染物来源的不同特征进行了对比分析。结果表明:冬春两个持续性霾过程均持续6天以上,达到重度霾和严重污染级别,冬季的更重,持续时间更长。霾发生时,出现高颗粒物粒子浓度、低地面风速和高相对湿度。细颗粒物在冬季个例中贡献更大,在春季影响重度霾的发生。冬春季过程发生在平直的环流形势且多短波槽脊、地面出现均压区的环流背景下,地面辐合线导致春季污染物的积聚。冬季逆温呈高低层分布,地面辐射降温、暖平流引发的增温是逆温层的形成机制。春季逆温层仅出现在地面附近,形成以地面辐射降温为主。重度霾时,冬季高浓度气溶胶粒子层聚集在1.0 km左右,以本地污染物的贴地传输为主。春季高浓度气溶胶粒子层聚集在1.5 km,受外来污染物传输和高层沙尘沉降的影响。弱上升运动、高湿度使冬季污染层高度偏低、强度偏大,春季的反之。冬季低逆温层造成1.2 km上下层污染物类型明显不同,春季逆温层偏高且弱使污染物类型分布均匀。

Using meteorological data,environmental monitoring data,CALIPSO satellite data and the backward trajectory data calculated by HYSPLIT model,this paper explores the evolution characteristics and impact factors of the sustained hazy processes in the central part of Shandong province from 2015 to 2016,and comparatively analyizes the different characteristics of meteorological conditions,aerosol particle distribution and pollutant sources of two persistent hazy processes.The results show that the two persistent haze processes,which reached heavy haze and serious pollution,both lasted for more than 6 days,and the winter process was even heavier lasting even longer.Haze usually occurs with high particle concentration,low surface wind speed and high relative humidity.Fine particulate matter contributes more in winter and also affects the occurrence of heavy haze in spring.The straight circulation,short-wave trough and ridge,and the surface uniform pressure provide stable atmospheric circulation situation.The surface convergence lines lead to the accumulation of pollutants in spring.In winter,the temperature inversion is distributed in high and low layers.The surface radiation cooling accompanied with warm advection is the formation mechanism of the inversion layer.In the spring case,the inversion layer only appears near the surface,and its formation is dominated by surface radiation cooling.In the winter heavy haze period,the high concentration aerosol particle layer,which is mainly composed of local pollutants,aggregates at the height of 1.0 km or so.In spring,the high concentration aerosol layer accumulates at the height about 1.5 km.The main pollution source is the pollutants from other places and the sedimentation of high-level sand and dust.The weak upward motion and high humidity lead to the low height and high intensity of the pollution layer in winter,but the situation is opposite in spring.The low inversion layer results in a significant difference in the pollutant types of the upper and lower layers of 1.2 km in winter while the high and weak inversion layer makes the pollutants evenly distributed.