Observations of particle extinction, PM2.5 mass concentration profile and flux in north China based on mobile lidar technique
Observations of particle extinction, PM2.5 mass concentration profile and flux in north China based on mobile lidar technique
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基于移动激光雷达技术的华北地区颗粒物消光、PM2.5质量浓度剖面及通量观测
DOI：
10.1016/j.atmosenv.2017.06.022
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发表时间：
2017
影响因子：
5
通讯作者：
Xiaowen Shu
中科院分区：
文献类型：
--
作者：
Lihui Lv;Wenqing Liu;Tianshu Zhang;Zhenyi Chen;Yunsheng Dong;Guangqiang Fan;Yan Xiang;Yawei Yao;Nan Yang;Baolin Chu;Man Teng;Xiaowen Shu
粒径<2.5 μm的细颗粒物（PM2.5）对人类的生活和活动有着重要的直接和间接影响。然而，细颗粒物的研究受到限制，缺乏监测数据的多个固定站点的采样策略。移动的监测提供了广泛测量细颗粒的手段。在这项研究中，讨论了移动的激光雷达在绘制细颗粒物分布和传输地图方面的潜在用途。利用车载移动的激光雷达和风场资料，研究了大气边界层中颗粒物消光、PM2. 5质量浓度和细颗粒物区域输送通量的时空分布特征。以北京市为例，分析了不同污染水平下区域交通的贡献。利用车载移动的激光雷达系统，获得了测量路径上粒子消光的时空分布。在北京的中国科学院大学（UCAS），定点激光雷达和颗粒物采样器相邻操作，以确定颗粒消光系数与PM2. 5质量浓度之间的关系。当相对湿度小于90%时，颗粒物消光系数与PM2.5质量浓度的相关系数R2大于0.8。一个中尺度气象模式，天气研究和预报（WRF）模式，被用来获得的水平风速，风向和相对湿度的廓线。利用车载移动的激光雷达技术，结合PM2. 5廓线和垂直廓线风场数据，对大气输送通量进行了估算。该方法适用于吸湿生长可以忽略不计的情况（相对湿度<90%）。在实验中发现西南是北京的主要通道。
Fine particle with diameter <2.5 μm (PM2.5) have important direct and indirect effects on human life and activities. However, the studies of fine particle were limited by the lack of monitoring data obtained with multiple fixed site sampling strategies. Mobile monitoring has provided a means for broad measurement of fine particles. In this research, the potential use of mobile lidar to map the distribution and transport of fine particles was discussed. The spatial and temporal distributions of particle extinction, PM2.5mass concentration and regional transport flux of fine particle in the planetary boundary layer were investigated with the use of vehicle-based mobile lidar and wind field data from north China. Case studies under different pollution levels in Beijing were presented to evaluate the contribution of regional transport. A vehicle-based mobile lidar system was used to obtain the spatial and temporal distributions of particle extinction in the measurement route. Fixed point lidar and a particulate matter sampler were operated next to each other at the University of Chinese Academy of Science (UCAS) in Beijing to determine the relationship between the particle extinction coefficient and PM2.5mass concentration. The correlation coefficient (R2) between the particle extinction coefficient and PM2.5mass concentration was found to be over 0.8 when relative humidity (RH) was less than 90%. A mesoscale meteorological model, the Weather Research and Forecasting (WRF) model, was used to obtain profiles of the horizontal wind speed, wind direction and relative humidity. A vehicle-based mobile lidar technique was applied to estimate transport flux based on the PM2.5profile and vertical profile of wind data. This method was applicable when hygroscopic growth can be neglected (relatively humidity<90%). Southwest was found to be the main pathway of Beijing during the experiments.