Five-year observation of aerosol optical properties and its radiative effects to planetary boundary layer during air pollution episodes in North China: Intercomparison of a plain site and a mountainous site in Beijing

Yu Zheng; Huizheng Che; Xiangao Xia; Yaqiang Wang; Hong Wang; Yunfei Wu; Jun Tao; Hujia Zhao; Linchang An; Lei Li; Ke Gui; Tianze Sun; Xiaopan Li; Zhizhong Sheng; Chao Liu; Xianyi Yang; Yuanxin Liang; Lei Zhang; Chong Liu; Xiang Kuang; Shi Luo; Yingchang You; Xiaoye Zhang

doi:10.1016/j.scitotenv.2019.03.418

Five-year observation of aerosol optical properties and its radiative effects to planetary boundary layer during air pollution episodes in North China: Intercomparison of a plain site and a mountainous site in Beijing

Sci Total Environ. 2019 Jul 15:674:140-158. doi: 10.1016/j.scitotenv.2019.03.418. Epub 2019 Mar 31.

Authors

Yu Zheng¹, Huizheng Che², Xiangao Xia³, Yaqiang Wang⁴, Hong Wang⁴, Yunfei Wu⁵, Jun Tao⁶, Hujia Zhao⁴, Linchang An⁷, Lei Li⁴, Ke Gui⁴, Tianze Sun⁴, Xiaopan Li⁴, Zhizhong Sheng⁴, Chao Liu⁸, Xianyi Yang⁴, Yuanxin Liang⁴, Lei Zhang⁴, Chong Liu⁹, Xiang Kuang¹⁰, Shi Luo¹⁰, Yingchang You¹⁰, Xiaoye Zhang⁴

Affiliations

¹ 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.
² State Key Laboratory of Severe Weather (LASW) and Institute of Atmospheric Composition, Chinese Academy of Meteorological Sciences, CMA, Beijing 100081, China. Electronic address: chehz@cma.gov.cn.
³ Laboratory for Middle Atmosphere and Global Environment Observation (LAGEO), Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029, China; School of Geoscience University of Chinese Academy of Science, Beijing 100049, China.
⁴ State Key Laboratory of Severe Weather (LASW) and Institute of Atmospheric Composition, Chinese Academy of Meteorological Sciences, CMA, Beijing 100081, China.
⁵ CAS Key Laboratory of Regional Climate-Environment for Temperate East Asia (RCE-TEA), Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029, China.
⁶ South China Institute of Environmental Sciences, Ministry of Environmental Protection, Guangzhou 510655, China.
⁷ National Meteorological Center, CMA, Beijing 100081, China.
⁸ State Key Laboratory of Severe Weather (LASW) and Institute of Atmospheric Composition, Chinese Academy of Meteorological Sciences, CMA, Beijing 100081, China; School of Surveying and Land Information Engineering, Henan Polytechnic University, Henan 454000, China.
⁹ School of Atmospheric Sciences, Nanjing University, Nanjing 210093, China.
¹⁰ 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.

PMID: 31004891
DOI: 10.1016/j.scitotenv.2019.03.418

Abstract

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^-2, respectively, and the maximum atmospheric heating was found in summer (~66 ± 12 W m^-2). 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.

Keywords: Aerosol optical properties; Beijing; Dust; Haze; Planetary boundary layer; Radiative effects.