基于加密探空观测的成都市一次重霾污染过程中大气边界层气溶胶垂直结构分析  

Observation analysis of aerosol vertical structures in boundary layer during a heavy haze event in Chengdu based on intensive sounding measurements

作　　者：曹蔚 赵天良[1] 徐祥德[3] 张小曳[3] 郑小波 杨富燕 夏俊荣[1] 曹乐[1] 邱玉珺[1] 谷晓平 CAO Wei;ZHAO Tian-liang;XU Xiang-de;ZHANG Xiao-ye;ZHENG Xiao-bo;YANG Fu-yan;XIA Jun-rong;CAO Le;QIU Yu-jun;GU Xiao-ping(Key Laboratory for Aerosol-Cloud-Precipitation of China Meteorological Administration,Collaborative In-novation Center on Forecast and Evaluation of Meteorological Disasters,Joint International Research Laboratory of Climate and Environment Change,Key Laboratory of Meteorological Disaster,Ministry of Education,Nanjing University of Information Science and Technology,Nanjing 210044,China;Guizhou Climate Center,Guiyang 550002,China;State Key Laboratory of Severe Weather,Chinese Academy of Meteorological Sciences,Beijing 100081,China;Guizhou Institute of Mountainous Climate and Environment,Guiyang 550002,China)

机构地区：[1]南京信息工程大学,气象灾害教育部重点实验室,气候与环境变化国际合作联合实验室,气象灾害预报预警与评估协同创新中心,中国气象局气溶胶与云降水重点开放实验室,江苏南京210044 [2]贵州省气候中心,贵州贵阳550002 [3]中国气象科学研究院灾害天气国家重点实验室,北京100081 [4]贵州省山地环境气候研究所,贵州贵阳550002

出　　处：《地球化学》2020年第3期344-352,共9页Geochimica

基　　金：国家重点基础研究发展计划(2016YFC0203304);国家自然科学基金(91544109,91644223)。

摘　　要：基于2017年1月4日至7日成都市一次重霾污染过程的系留汽艇探测的低层大气气象要素和大气颗粒物垂直探空加密观测资料,分析了大气边界层结构及气溶胶垂直分布。结果表明,此次重霾污染期间,大气边界层昼夜变化特征基本消失。稳定边界层结构出现25次,对流边界层结构仅出现3次,大气边界层结构趋于稳定,边界层高度普遍在700 m以下。霾污染发生、维持及消散阶段大气边界层气溶胶垂直结构具有明显差异。霾污染发生阶段,大气边界层气溶胶粗、细粒子主要集中在300 m高度以下,近地面层大气气溶胶粒子累积触发霾污染事件;霾维持阶段,大气颗粒物粒子浓度数垂直方向趋于一致,大气边界层稳定结构中存在强的大气垂直混合作用;在霾消散阶段,较高处的气溶胶粒子浓度最先下降,且下降幅度最大,表明对流层自由大气作用对霾污染消散具有影响。大气边界层风速的增大加剧了大气传输扩散。温度与大气颗粒物浓度在近地层呈负相关关系,在100 m高度以上呈正相关关系。大气边界层低层偏冷,高层偏暖的稳定大气热力层结减弱了大气污染物的垂直扩散。相对湿度的增加有利于气溶胶粒子的吸湿增长和液相化学反应,加剧了霾污染。The vertical distributions of aerosol number concentrations and boundary layer structures were intensively measured using a kite balloon during a heavy haze event from January 4 to 7,2017,in Chengdu,southwest China.This study analyzed the aerosol vertical distribution and atmospheric boundary layer structures based on those measurements.The analysis showed that during heavy haze pollution,the diurnal changes in the atmospheric boundary layer basically disappeared with the stable boundary layer structure 25 times and with the convective boundary layer structure only 3 times.The boundary layer structure tended to be stable.The vertical distribution of aerosol particles varied distinctly during the beginning,persistent,and dissipation stages of the heavy haze event.During the beginning stage,aerosol particles decreased vertically with height and atmospheric particles accumulated in the surface layer,thereby triggering the haze event;in the persistent phase,the aerosol number concentration was kept almost consistent vertically below 1000 m,thereby indicating strong vertical mixing in the stable boundary layer;in the haze dissipation phase,the concentrations of aerosol particles decreased earlier at the higher levels,thereby reflecting the influence of the free atmosphere on the dispersion of the stable boundary layer with haze pollution.Based on the analysis of the influence of the dynamic and thermal factors of the boundary layer on the aerosol number concentrations,we found that strong wind intensified the aerosol diffusion in the atmosphere.The air temperature and atmospheric particle concentrations were negatively correlated at the near surface and positively correlated above the height of 100 m with the enhancement of thermal stability weakening the vertical mixing of aerosols.The increase in relative humidity was conducive to the hygroscopic growth and liquid phase chemical reactions of aerosol particles,thereby exacerbating the haze pollution.

关 键 词：霾污染 大气气溶胶 垂直分布 大气边界层 四川盆地 

分 类 号：P593[天文地球—地球化学] X513[天文地球—地质学]