陕西关中两次霾重污染过程气象条件分析  

Analysis of Meteorological Conditions for Two Air Pollution Events in Guanzhong Region

作　　者：黄少妮[1] 孟金平[2] 杜莉丽[1] 刘慧 Huang Shaoni;Meng Jinping;Du Lili;Liu Hui(Shaanxi Meteorological Observatory,Xi'an 710014;Beijing Meteorological Service,Beijing 100089)

机构地区：[1]陕西省气象台,西安710014 [2]北京市气象局,北京100089

出　　处：《气象科技》2019年第5期809-817,共9页Meteorological Science and Technology

基　　金：中国气象局预报员专项（CMAYBY2018-074）“陕西智能网格预报协同技术总结分析及改进”资助

摘　　要：应用常规观测资料、污染物浓度资料和NCEP 1°×1°再分析资料从环流形势、边界层特征和扩散条件等方面对2013年和2016年两次持续性霾重污染过程进行对比分析。结果表明:①2013年过程和2016年过程在500hPa高空上分别为阻塞环流型和纬向环流型,关中地区受偏西气流影响、地面气压场较弱、大气层结均比较稳定;②2013年过程西安贴地逆温层顶高度低、相对湿度大、气温低、不利于大气垂直湍流交换,污染物容易堆积,这也是2013年过程比2016年过程重污染持续时间长、污染浓度高的原因之一;③两次过程西安平均风速均小于2m/s,具有显著的低风速特征,且东北风为其主导风向。持续东北风引起上游污染传输和低风速导致的本地污染累积是造成2013年过程污染浓度更高的重要因素;④2013年过程结束是受强冷空气影响,来自高空的干洁大气下沉到地面,置换了边界层的污染空气,使空气质量得到根本改善;而2016年过程是受高原槽东移影响,雨雪天气的沉降作用使得霾消散。Based on the conventional observational data,the observational PM2.5 concentration and NCEP reanalysis data,a comparative analysis is conducted on the atmospheric conditions,boundary layer characteristics of two serious air pollution events which took place in 2013 and 2016,respectively.The results are:(1)At 500 hPa,the processes of 2013 and 2016 were controlled by the blocking circulation and zonal circulation,respectively.The Guanzhong area was affected by the westerly flow;the surface pressure field was weak,and the atmospheric stratification was relatively stable.(2)In the 2013 event,the inversion layer near the ground in Xi’an was low;the relative humidity was high;the temperature was low;which is not conducive to the vertical turbulence exchange and in which the pollutants were easy to accumulate.It is one of the reasons that the process of 2013 heavy pollution lasted longer and the concentration of pollutants was higher than that of 2016.(3)Both heavy pollution processes in Xi’an had the significant low wind speed characteristic,and the northeast wind was the dominant wind direction.The2013 process is the result of the combination of local pollution accumulation and upstream pollution transmission.(4)The process of 2013 was affected by cold air,and the continuous dry and cold northeast wind made haze dissipate in the Guanzhong area;while the process of 2016 was affected by the plateau trough,and rain and snow weather made pollutants deposite and haze dissipate.

关 键 词：关中 霾 重污染 气象条件 

分 类 号：P458[天文地球—大气科学及气象学]