Zheng Yu, Che Huizheng, Xia Xiangao, Wang Yaqiang, Wang Hong, Wu Yunfei, Tao Jun, Zhao Hujia, An Linchang, Li Lei, Gui Ke, Sun Tianze, Li Xiaopan, Sheng Zhizhong, Liu Chao, Yang Xianyi, Liang Yuanxin, Zhang Lei, Liu Chong, Kuang Xiang, Luo Shi, You Yingchang, Zhang Xiaoye
Key Laboratory of Meteorological Disaster, Ministry of Education/Joint International Research Laboratory of Climate and Environment Change/Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters/Key Laboratory for Aerosol-Cloud-Precipitation of China Meteorological Administration, Nanjing University of Information Science &Technology, Nanjing 210044, China; State Key Laboratory of Severe Weather (LASW) and Institute of Atmospheric Composition, Chinese Academy of Meteorological Sciences, CMA, Beijing 100081, China.
State Key Laboratory of Severe Weather (LASW) and Institute of Atmospheric Composition, Chinese Academy of Meteorological Sciences, CMA, Beijing 100081, China.
Sci Total Environ. 2019 Jul 15;674:140-158. doi: 10.1016/j.scitotenv.2019.03.418. Epub 2019 Mar 31.
The aerosol microphysical, optical and radiative properties of the whole column and upper planetary boundary layer (PBL) were investigated during 2013 to 2018 based on long-term sun-photometer observations at a surface site (106 m a.s.l.) and a mountainous site (1225 m a.s.l.) in Beijing. Raman-Mie lidar data combined with radiosonde data were used to explore the aerosol radiative effects to PBL during dust and haze episodes. The results showed size distribution exhibited mostly bimodal pattern for the whole column and the upper PBL throughout the year, except in July for the upper PBL, when a trimodal distribution occurred due to the coagulation and hygroscopic growth of fine particles. The seasonal mean values of aerosol optical depth at 440 nm for the upper PBL were 0.31 ± 0.34, 0.30 ± 0.37, 0.17 ± 0.30 and 0.14 ± 0.09 in spring, summer, autumn and winter, respectively. The single-scattering albedo at 440 nm of the upper PBL varied oppositely to that of the whole column, with the monthly mean value between 0.91 and 0.96, indicating weakly to slightly strong absorptive ability at visible spectrum. The monthly mean direct aerosol radiative forcing at the Earth's surface and the top of the atmosphere varied from -40 ± 7 to -105 ± 25 and from -18 ± 4 to -49 ± 17 W m, respectively, and the maximum atmospheric heating was found in summer (~66 ± 12 W m). From a radiative point of view, during dust episode, the presence of mineral dust heated the lower atmosphere, thus promoting vertical turbulence, causing more air pollutants being transported to the upper air by the increasing PBLH. In contrast, during haze episode, a large quantity of absorbing aerosols (such as black carbon) had a cooling effect on the surface and a heating effect on the upper atmosphere, which favored the stabilization of PBL and occurrence of inversion layer, contributing to the depression of the PBLH.
基于北京一个地面站点（海拔约106米）和一个山区站点（海拔约1225米）的长期太阳光度计观测数据，对2013年至2018年期间整层大气和气旋上部行星边界层（PBL）的气溶胶微观物理、光学和辐射特性进行了研究。利用拉曼-米氏激光雷达数据结合无线电探空仪数据，探讨了沙尘和雾霾事件期间气溶胶对行星边界层的辐射效应。结果表明，除了7月的行星边界层上部因细颗粒物的凝聚和吸湿增长出现三峰分布外，全年整层大气和行星边界层上部的气溶胶粒径分布大多呈现双峰模式。行星边界层上部在440纳米处的气溶胶光学厚度的季节平均值在春季、夏季、秋季和冬季分别为0.31±0.34、0.30±0.37、0.17±0.30和0.14±0.09。行星边界层上部在440纳米处的单次散射反照率与整层大气的情况相反，月平均值在0.91至0.96之间，表明在可见光谱范围内具有弱到中等强度的吸收能力。地球表面和大气顶部的月平均直接气溶胶辐射强迫分别在-40±7至-105±25瓦/平方米和-18±4至-49±17瓦/平方米之间变化，夏季出现最大的大气加热（约66±12瓦/平方米）。从辐射角度来看，在沙尘事件期间，矿物尘埃的存在加热了低层大气，从而促进了垂直湍流，导致更多的空气污染物随着行星边界层高度的增加被输送到高层大气中。相反，在雾霾事件期间，大量的吸收性气溶胶（如黑碳）对地表有冷却作用，对高层大气有加热作用，这有利于行星边界层的稳定和逆温层的出现，导致行星边界层高度降低。
