基于激光雷达对一次沙尘过程臭氧和气溶胶垂直结构的协同观测  

Collaborative Observation of Vertical Structures of Ozone and Aerosol in a Dust Episode Based on Lidar

作　　者：王界 刘文清 张天舒[1] 夏建东 邓威 胡文杰 WANG Jie;LIU Wen-qing;ZHANG Tian-shu;XIA Jian-dong;DENG Wei;HU Wen-jie(Institutes of Physical Science and Information Technology,Anhui University,Hefei 230061,China;Institute of Environment,Hefei Comprehensive National Science Center,Hefei 230031,China;Information Materials and Intelligent Sensing Laboratory of Anhui Province,Anhui University,Hefei 230061,China;Key Laboratory of Environmental Optics and Technology,Anhui Institutes of Optics and Fine Mechanics,Chinese Academy of Sciences,Hefei 230031,China;Anhui Shufeng Environmental Technology Development Co.,Ltd.,Hefei 230031,China)

机构地区：[1]安徽大学物质科学与信息技术研究院,安徽合肥230061 [2]合肥综合性科学中心环境研究院,安徽合肥230031 [3]安徽大学信息材料与智能感知安徽省实验室,安徽合肥230061 [4]中国科学安徽光学精密机械研究所,中国科学院环境光学与技术重点实验室,安徽合肥230031 [5]安徽蜀峰环境科技发展有限公司,安徽合肥230031

出　　处：《光谱学与光谱分析》2023年第7期2258-2265,共8页Spectroscopy and Spectral Analysis

基　　金：研究合肥市大气污染特征和演变规律项目(2020BFFFD01804);中国工程院战略研究与咨询项目(2022-06-04);天津市科技计划项目(22ZLGCGX00020)资助。

摘　　要：利用自主研制的四波长全固态激光雷达系统,实现了大气臭氧和气溶胶的协同观测,这也是该系统在国内的首次立体观测应用。基于该雷达系统,重点针对2021年4月中旬沙尘污染前、中、后三个阶段进行污染物的空间垂直分布特征进行分析,发现臭氧的垂直分布主要集中在距地面1.5 km范围内,沙尘前的臭氧浓度整体明显高于沙尘中和沙尘后。沙尘前和沙尘中,气溶胶的垂直分布高度可以达到2.5 km,由于沙尘的突然入境,会造成局地消光系数突变升高超过2.5 km^(-1),沙尘过境后气溶胶主要积累在近地面500 m范围内。通过激光雷达的连续观测和垂直廓线分析发现沙尘前,在上午7时前后城市上空距地面300 m高度附近会出现臭氧浓度的低值区,约13μg·m^(-3),不足附近范围的1/4,这可能是在稳定大气环境中由日出前的“滴定效应”造成。但是,沙尘的突然输入不仅消除了该稳定的“滴定效应”,而且还抹平了臭氧的日变化特征,使得近地面的臭氧浓度峰谷值降为55μg·m^(-3),是沙尘前和沙尘后的0.44倍和0.46倍。同时,由于沙尘的输入,细颗粒物质量浓度的占比降低至不足20%,加之上游一次污染物输入,进一步抑制了臭氧的生成和转化过程。The cooperative observation of atmospheric ozone and aerosol is realized by using the self-developed four-wavelength solid-state lidar system,which is also the first three-dimensional observation application of the system in China.Based on the radar system,the spatial vertical distribution characteristics of pollutants before,during and after a dust episodein Mid-April 2021 were studied.We found that the vertical distribution of ozone was mainly concentrated within 1.5 km from the ground,and the ozone concentration before the dust was significantly higher than during and after dust.The vertical distribution of aerosol could reach the height of 2.5 km before and in the dust.Due to the sudden entry of dust,the local extinction coefficient will increase abruptly by more than 2.5 km^(-1).After the passage of sand dust,the aerosol was mainly suppressed within 500 m near the ground.Through the continuous observations and the vertical-profile analysis of lidar,it is found that before the dust,a region of low ozone concentration with a minimum concentration of 13μg·m^(-3)near the height of 300 m around 7 a.m.was displayed,which is about 1/4 of the nearby region.This low ozone region may be caused by the“titration effect”before sunrise in a stable atmospheric environment.However,the sudden input of dust not only eliminated the stable“titration effect”but also erasesd the daily variation of ozone by reducing the peak-to-valley value of ozone concentration on the ground to 55μg·m^(-3),which was 0.44 and 0.46 times that before and after dust respectively.Meanwhile,the input of dust,reduced the proportion of fine particle mass concentration to less than 20%and transported more primary pollutants from upstream,further inhibiting the generation and transformation of ozone.

关 键 词：激光雷达 沙尘 垂直结构 臭氧 协同观测 

分 类 号：TN958.98[电子电信—信号与信息处理]