Influence of atmospheric in-cloud aqueous-phase chemistry on the global simulation of SO.sub.2 in CESM2

Sulfur dioxide (SO.sub.2) is a major atmospheric pollutant and precursor of sulfate aerosols, which influences air quality, cloud microphysics, and climate. Therefore, better understanding the conversion of SO.sub.2 to sulfate is essential to simulate and predict sulfur compounds more accurately. Th...

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Bibliographic Details
Published inAtmospheric chemistry and physics Vol. 21; no. 21; pp. 16093 - 32185
Main Authors Ge, Wendong, Liu, Junfeng, Yi, Kan, Xu, Jiayu, Zhang, Yizhou, Hu, Xiurong, Ma, Jianmin, Wang, Xuejun, Wan, Yi, Hu, Jianying, Zhang, Zhaobin, Wang, Xilong, Tao, Shu
Format Journal Article
LanguageEnglish
Published Copernicus GmbH 02.11.2021
Subjects
Air quality
Atmospheric physics
Clouds
Comparative analysis
Sulfates
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Summary:Sulfur dioxide (SO.sub.2) is a major atmospheric pollutant and precursor of sulfate aerosols, which influences air quality, cloud microphysics, and climate. Therefore, better understanding the conversion of SO.sub.2 to sulfate is essential to simulate and predict sulfur compounds more accurately. This study evaluates the effects of in-cloud aqueous-phase chemistry on SO.sub.2 oxidation in the Community Earth System Model version 2 (CESM2). We replaced the default parameterized SO.sub.2 aqueous-phase reactions with detailed HO.sub.x, Fe, N, and carbonate chemistry in cloud droplets and performed a global simulation for 2014-2015. Compared with the observations, the results incorporating detailed cloud aqueous-phase chemistry greatly reduced SO.sub.2 overestimation. This overestimation was reduced by 0.1-10 ppbv (parts per billion by volume) in most of Europe, North America, and Asia and more than 10 ppbv in parts of China. The biases in annual simulated SO.sub.2 mixing ratios decreased by 46 %, 41 %, and 22 % in Europe, the USA, and China, respectively. Fe chemistry and HO.sub.x chemistry contributed more to SO.sub.2 oxidation than N chemistry. Higher concentrations of soluble Fe and higher pH values could further enhance the oxidation capacity. This study emphasizes the importance of detailed in-cloud aqueous-phase chemistry for the oxidation of SO.sub.2 . These mechanisms can improve SO.sub.2 simulation in CESM2 and deepen understanding of SO.sub.2 oxidation and sulfate formation.
ISSN:1680-7316
1680-7324