摘要
2023年3月19-25日阳泉市出现近3年来强度最强、影响范围最广的混合型重污染天气过程。通过对该时段空气质量数据、气象监测数据、微波辐射计数据及后向轨迹进行分析,并采用二分K均值算法对后向轨迹聚类,结果发现:(1)本次污染过程可分为霾、沙尘、沙尘转霾3个阶段。第一阶段受静稳天气影响,地面风速小,为霾天气阶段;第二阶段受蒙古气旋东移南下影响,PM_(10)浓度暴发式增长,是沙尘天气阶段;第三阶段受回流天气影响,地面风速减小,大气中PM_(10)受重力影响逐步沉降,PM_(2.5)再次逐渐累积,是沙尘转霾天气阶段。(2)污染物的输送通道轨迹分为3类,从空间特征来看,霾天气的输送路径在垂直方向上呈现先下沉再抬升的现象;从输送速度来看,沙尘天气移动速度高于霾天气的。(3)春季混合型污染天气出现时,霾天气的地面形势多为鞍形场、暖低压型和高压后部型,高空形势多为平直纬向环流;沙尘天气的地面形势多为高压前部(底部)型,高空形势多为梯度较大的经向环流。(4)气态污染物(SO2和NO2)浓度受近地面风场影响较大,且在沙尘天气和霾天气时段呈现截然不同的变化特征。(5)微波辐射计3.0 km以下,特别是边界层内的温度廓线和水汽密度廓线资料能弥补本地无常规探空资料的不足,利用边界层内的温度廓线可以提前发现贴地逆温。
From March 19 to 25,2023,a mixed heavy pollution weather process with the strongest intensity and widest influence in the past three years occurred in Yangquan City,Shanxi Province.Through analyzing the air quality data,meteorological monitoring data,microwave radiometer data,and backward trajectory during this period,the backward trajectories are clustered by means of the binary Kmeans algorithm.The results show that:(1)This heavy pollution process is divided into three stages:from the haze stage to the sand-dust stage,and then to the sand-dust to haze stage.The first stage was the haze weather stage,affected by static-stable weather with low surface wind speed.The second stage was the stage of sand-dust weather,affected by the Mongolian cyclone that moved eastward and southward,causing the PM_(10) concentration to increase explosively.The third stage was the sand-dust to haze stage,which was affected by reflux weather.During this stage,the surface wind speed was reduced,the PM_(10) in the atmosphere gradually settled down as the result of gravity,making the PM_(2.5) gradually accumulate again.(2)The transport paths of pollutants during this heavy pollution process are divided into three categories.Spatially,the pollutant transport path in haze weather was first downward and then upward in the vertical direction.In terms of the pollutant transport speed,the moving speed of sand and dust was higher than that in the haze weather.(3)When the mixed pollution weather appeared in spring,the surface situation of haze weather was mostly saddle-shaped field,warm low-pressure type and highpressure rear type,and the upper situation was mostly flat zonal circulation.The surface situation of sand-dust weather was mostly the high-pressure front(bottom)type,and the upper situation was mostly the meridional circulation with large gradient.(4)The concentrations of gaseous pollutants(SO2 and NO2)were greatly affected by the near-surface wind field,presenting different characteristics in the period of dust and haze weather.(5)Below the height of 3.0 km,the temperature profile and water vapor density profile data in the boundary layer can make up for the lack of local conventional radiosonde data.Moreover,according to the temperature profile in the boundary layer,the ground inversion can be observed in advance.
作者
马星芬
王雁
闫世明
王韫戬
贾立亭
穆昌俊
Ma Xingfen;Wang Yan;Yan Shiming;Wang Yunjian;Jia Liting;Mu Changjun(Yangquan Meteorological Office of Shanxi Province,Yangquan 045000,China;Shanxi Institute of Meteorological Sciences,Taiyuan 030002,China;Shanxi Institute of Energy,Jinzhong 030600,China)
出处
《气象与环境科学》
2025年第4期80-88,共9页
Meteorological and Environmental Sciences
基金
山西省自然科学基金项目(201901D111465)
山西省基础研究计划(202403021221337)
山西省基础研究计划青年基金项目(202203021222423)
山西省气象局“揭榜挂帅”项目(SXKJBGS202403)。
