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Climate Impacts of the Biomass Burning in Indochina on Atmospheric Conditions over Southern China

Category: Aerosol and Atmospheric Chemistry

Volume: 19 | Issue: 12 | Pages: 2707-2720
DOI: 10.4209/aaqr.2019.01.0028
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To cite this article:
Huang, L., Lin, W., Li, F., Wang, Y., Jiang, B. (2019). Climate Impacts of the Biomass Burning in Indochina on Atmospheric Conditions over Southern China. Aerosol Air Qual. Res. Volume: 2613-2624. doi: 10.4209/aaqr.2019.01.0028.

Lina Huang1, Wenshi Lin 1,2, Fangzhou Li3, Yuan Wang4, Baolin Jiang3

  • 1 School of Atmospheric Sciences and Guangdong Province Key Laboratory for Climate Change and Natural Disaster Studies, Sun Yat-sen University, Guangzhou, Guangdong 510275, China
  • 2 Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Zhuhai 519082, China
  • 3 School of Atmospheric Sciences, Sun Yat-sen University, Guangzhou 519082, China
  • 4 Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA 91106, USA

Highlights

  • Aerosol indirect effect plays a greater role in removing aerosols than radiative one.
  • Air is drier and hotter under radiative effect, but indirect effect is the opposite.
  • Under solely aerosol radiative effect, BB aerosols would remain longer in the air.

Abstract

Substantial biomass burning (BB) activities in Indochina during March and April of each year generate aerosols that are transported via westerly winds to southern China. These BB aerosols have both radiative (direct and semi-direct) and indirect effects on the climate. This study evaluates impacts of BB in Indochina during April 2013 on atmospheric conditions in southern China using WRF-Chem sensitivity simulations. We show that the atmosphere becomes drier and hotter under the aerosol radiative effect in southern China, while the changes linked to the indirect effect are opposite. The former (the latter) rises (reduces) surface temperature 0.13°C (0.19°C) and decrease (increase) water vapor mixing ratios 0.23 g kg–1 (0.40 g kg–1) at 700 hPa. Atmospheric responses to aerosols in turn affect aerosol dissipation. Specifically, BB aerosols absorb solar radiation and heat the local atmosphere, which inhibits the formation of clouds (reducing low-level cloud about 7%) related to the aerosol semi-direct effect. Less cloud enhances surface solar radiation flux and temperature. Otherwise, northeasterly winds linked to radiative effect suppress water vapor transport. In this case, precipitation reduces 1.09 mm day–1, diminishing wet removal and westward transport of aerosols. Under the indirect effect, greater cloud coverage is formed, which reduces surface solar radiation flux and increases local latent heat release. This extra heating promotes air convection and diffusion of pollution. Regional mean precipitation increases 0.49 mm d–1, facilitating wet pollution removal. Under indirect effect, aerosol extinction coefficient reduces 0.011 km–1 at 2-km height over southern China. However, it increases around 0.002 km–1 at 3-km height over southernmost China related to radiative effect. Therefore, atmospheric changes linked to indirect effect play a greater role in removing pollutants from the atmosphere than radiative effect over southern China.

Keywords

Aerosol radiative effect Aerosol indirect effect Cloud cover WRF-Chem Latent heat


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