Aerosol vertical mass flux measurements during heavy aerosol pollution episodes at a rural site and an urban site in the Beijing area of the North China Plain

Aerosol vertical mass flux measurements during heavy aerosol pollution episodes at a rural site and an urban site in the Beijing area of the North China Plain

<p>Due to excessive anthropogenic emissions, heavy aerosol pollution episodes (HPEs) often occur during winter in the Beijing–Tianjin–Hebei (BTH) area of the North China Plain. Extensive observational studies have been carried out to understand the causes of HPEs; however, few measurements of...

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Main Authors: R. Yuan, X. Zhang, H. Liu, Y. Gui, B. Shao, X. Tao, Y. Wang, J. Zhong, Y. Li, Z. Gao
Format: Article
Language:English
Published: Copernicus Publications 2019-10-01
Series:Atmospheric Chemistry and Physics
Online Access:https://www.atmos-chem-phys.net/19/12857/2019/acp-19-12857-2019.pdf
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record_format Article
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language English
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author R. Yuan
X. Zhang
X. Zhang
H. Liu
Y. Gui
B. Shao
X. Tao
Y. Wang
J. Zhong
Y. Li
Z. Gao
spellingShingle R. Yuan
X. Zhang
X. Zhang
H. Liu
Y. Gui
B. Shao
X. Tao
Y. Wang
J. Zhong
Y. Li
Z. Gao
Aerosol vertical mass flux measurements during heavy aerosol pollution episodes at a rural site and an urban site in the Beijing area of the North China Plain
Atmospheric Chemistry and Physics
author_facet R. Yuan
X. Zhang
X. Zhang
H. Liu
Y. Gui
B. Shao
X. Tao
Y. Wang
J. Zhong
Y. Li
Z. Gao
author_sort R. Yuan
title Aerosol vertical mass flux measurements during heavy aerosol pollution episodes at a rural site and an urban site in the Beijing area of the North China Plain
title_short Aerosol vertical mass flux measurements during heavy aerosol pollution episodes at a rural site and an urban site in the Beijing area of the North China Plain
title_full Aerosol vertical mass flux measurements during heavy aerosol pollution episodes at a rural site and an urban site in the Beijing area of the North China Plain
title_fullStr Aerosol vertical mass flux measurements during heavy aerosol pollution episodes at a rural site and an urban site in the Beijing area of the North China Plain
title_full_unstemmed Aerosol vertical mass flux measurements during heavy aerosol pollution episodes at a rural site and an urban site in the Beijing area of the North China Plain
title_sort aerosol vertical mass flux measurements during heavy aerosol pollution episodes at a rural site and an urban site in the beijing area of the north china plain
publisher Copernicus Publications
series Atmospheric Chemistry and Physics
issn 1680-7316
1680-7324
publishDate 2019-10-01
description <p>Due to excessive anthropogenic emissions, heavy aerosol pollution episodes (HPEs) often occur during winter in the Beijing–Tianjin–Hebei (BTH) area of the North China Plain. Extensive observational studies have been carried out to understand the causes of HPEs; however, few measurements of vertical aerosol fluxes exist, despite them being the key to understanding vertical aerosol mixing, specifically during weak turbulence stages in HPEs. In the winter of 2016 and the spring of 2017 aerosol vertical mass fluxes were measured by combining large aperture scintillometer (LAS) observations, surface PM<span class="inline-formula"><sub>2.5</sub></span> and PM<span class="inline-formula"><sub>10</sub></span> mass concentrations, and meteorological observations, including temperature, relative humidity (RH), and visibility, at a rural site in Gucheng (GC), Hebei Province, and an urban site at the Chinese Academy of Meteorological Sciences (CAMS) in Beijing located 100&thinsp;km to the northeast. These are based on the light propagation theory and surface-layer similarity theory. The near-ground aerosol mass flux was generally lower in winter than in spring and weaker in rural GC than in urban Beijing. This finding provides direct observational evidence for a weakened turbulence intensity and low vertical aerosol fluxes in winter and polluted areas such as GC. The HPEs included a transport stage (TS), an accumulative stage (AS), and a removal stage (RS). During the HPEs from 25 to 31 January 2017, in Beijing, the mean mass flux decreased by 51&thinsp;% from 0.0049&thinsp;mg&thinsp;m<span class="inline-formula"><sup>−2</sup></span>&thinsp;s<span class="inline-formula"><sup>−1</sup></span> in RSs to 0.0024&thinsp;mg&thinsp;m<span class="inline-formula"><sup>−2</sup></span>&thinsp;s<span class="inline-formula"><sup>−1</sup></span> in the TSs. During the ASs, the mean mass flux decreased further to 0.00087&thinsp;mg&thinsp;m<span class="inline-formula"><sup>−2</sup></span>&thinsp;s<span class="inline-formula"><sup>−1</sup></span>, accounting for approximately one-third of the flux in the TSs. A similar reduction from the TSs to ASs was observed in the HPE from 16 to 22 December 2016 in GC. It can be seen that from the TS to the AS, the aerosol vertical turbulent flux decreased, but the aerosol particle concentration within the surface layer increased, and it is inferred that in addition to the contribution of regional transport from upwind areas during the TS, suppression of vertical turbulence mixing confining aerosols to a shallow boundary layer increased accumulation.</p>
url https://www.atmos-chem-phys.net/19/12857/2019/acp-19-12857-2019.pdf
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spelling doaj-6ed019836fcb4d08a46f1c9092bda46e2020-11-25T02:37:29ZengCopernicus PublicationsAtmospheric Chemistry and Physics1680-73161680-73242019-10-0119128571287410.5194/acp-19-12857-2019Aerosol vertical mass flux measurements during heavy aerosol pollution episodes at a rural site and an urban site in the Beijing area of the North China PlainR. Yuan0X. Zhang1X. Zhang2H. Liu3Y. Gui4B. Shao5X. Tao6Y. Wang7J. Zhong8Y. Li9Z. Gao10School of Earth and Space Sciences, University of Science and Technology of China, Anhui 230026, ChinaState Key Laboratory of Severe Weather & Key Laboratory of Atmospheric Chemistry of CMA, Chinese Academy of Meteorological Sciences, Beijing 100081, ChinaCenter for Excellence in Regional Atmospheric Environment, IUE, CAS, Xiamen 361021, ChinaSchool of Earth and Space Sciences, University of Science and Technology of China, Anhui 230026, ChinaSchool of Earth and Space Sciences, University of Science and Technology of China, Anhui 230026, ChinaSchool of Earth and Space Sciences, University of Science and Technology of China, Anhui 230026, ChinaSchool of Physical Sciences, University of Science and Technology of China, Anhui 230026, ChinaState Key Laboratory of Severe Weather & Key Laboratory of Atmospheric Chemistry of CMA, Chinese Academy of Meteorological Sciences, Beijing 100081, ChinaState Key Laboratory of Severe Weather & Key Laboratory of Atmospheric Chemistry of CMA, Chinese Academy of Meteorological Sciences, Beijing 100081, ChinaSchool of Geography and Remote Sensing, Nanjing University of Information Science and Technology, Nanjing 210044, ChinaSchool of Geography and Remote Sensing, Nanjing University of Information Science and Technology, Nanjing 210044, China<p>Due to excessive anthropogenic emissions, heavy aerosol pollution episodes (HPEs) often occur during winter in the Beijing–Tianjin–Hebei (BTH) area of the North China Plain. Extensive observational studies have been carried out to understand the causes of HPEs; however, few measurements of vertical aerosol fluxes exist, despite them being the key to understanding vertical aerosol mixing, specifically during weak turbulence stages in HPEs. In the winter of 2016 and the spring of 2017 aerosol vertical mass fluxes were measured by combining large aperture scintillometer (LAS) observations, surface PM<span class="inline-formula"><sub>2.5</sub></span> and PM<span class="inline-formula"><sub>10</sub></span> mass concentrations, and meteorological observations, including temperature, relative humidity (RH), and visibility, at a rural site in Gucheng (GC), Hebei Province, and an urban site at the Chinese Academy of Meteorological Sciences (CAMS) in Beijing located 100&thinsp;km to the northeast. These are based on the light propagation theory and surface-layer similarity theory. The near-ground aerosol mass flux was generally lower in winter than in spring and weaker in rural GC than in urban Beijing. This finding provides direct observational evidence for a weakened turbulence intensity and low vertical aerosol fluxes in winter and polluted areas such as GC. The HPEs included a transport stage (TS), an accumulative stage (AS), and a removal stage (RS). During the HPEs from 25 to 31 January 2017, in Beijing, the mean mass flux decreased by 51&thinsp;% from 0.0049&thinsp;mg&thinsp;m<span class="inline-formula"><sup>−2</sup></span>&thinsp;s<span class="inline-formula"><sup>−1</sup></span> in RSs to 0.0024&thinsp;mg&thinsp;m<span class="inline-formula"><sup>−2</sup></span>&thinsp;s<span class="inline-formula"><sup>−1</sup></span> in the TSs. During the ASs, the mean mass flux decreased further to 0.00087&thinsp;mg&thinsp;m<span class="inline-formula"><sup>−2</sup></span>&thinsp;s<span class="inline-formula"><sup>−1</sup></span>, accounting for approximately one-third of the flux in the TSs. A similar reduction from the TSs to ASs was observed in the HPE from 16 to 22 December 2016 in GC. It can be seen that from the TS to the AS, the aerosol vertical turbulent flux decreased, but the aerosol particle concentration within the surface layer increased, and it is inferred that in addition to the contribution of regional transport from upwind areas during the TS, suppression of vertical turbulence mixing confining aerosols to a shallow boundary layer increased accumulation.</p>https://www.atmos-chem-phys.net/19/12857/2019/acp-19-12857-2019.pdf

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