| Emission-dominated gas exchange of elemental mercury vapor over natural surfaces in China |
| Xun Wang; Che-Jen Lin; Wei Yuan; Jonas Sommar; Wei Zhu; Xinbin Feng
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| 2016
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Source Publication | Atmospheric Chemistry and Physics
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Volume | 16Issue:17Pages:11125-11143 |
Abstract | Mercury (Hg) emission from natural surfaces plays an important role in global Hg cycling. The present estimate of global natural emission has large uncertainty and remains unverified against field data, particularly for terrestrial surfaces. In this study, a mechanistic model is developed for estimating the emission of elemental mercury vapor (Hg-0) from natural surfaces in China. The development implements recent advancements in the understanding of air-soil and air-foliage exchange of Hg-0 and redox chemistry in soil and on surfaces, incorporates the effects of soil characteristics and land use changes by agricultural activities, and is examined through a systematic set of sensitivity simulations. Using the model, the net exchange of Hg-0 between the atmosphere and natural surfaces of mainland China is estimated to be 465.1Mg yr(-1), including 565.5 Mg yr(-1) from soil surfaces, 9.0 Mg yr(-1) from water bodies, and 100.4 Mg yr(-1) from vegetation. The air-surface exchange is strongly dependent on the land use and meteorology, with 9% of net emission from forest ecosystems; 50% from shrubland, savanna, and grassland; 33% from cropland; and 8% from other land uses. Given the large agricultural land area in China, farming activities play an important role on the air-surface exchange over farmland. Particularly, rice field shift from a net sink (3.3 Mg uptake) during April-October (rice planting) to a net source when the farmland is not flooded (November-March). Summing up the emission from each land use, more than half of the total emission occurs in summer (51 %), followed by spring (28 %), autumn (13 %), and winter (8 %). Model verification is accomplished using observational data of airsoil/air-water fluxes and Hg deposition through litterfall for forest ecosystems in China and Monte Carlo simulations. In contrast to the earlier estimate by Shetty et al. (2008) that reported large emission from vegetative surfaces using an evapotranspiration approach, the estimate in this study shows natural emissions are primarily from grassland and dry cropland. Such an emission pattern may alter the current understanding of Hg emission outflow from China as reported by Lin et al. (2010b) because a substantial natural Hg emission occurs in West China. |
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Subject Area | 环境地球化学
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Indexed By | SCI
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Language | 英语
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Document Type | 期刊论文
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Identifier | http://ir.gyig.ac.cn/handle/352002/6536
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Collection | 环境地球化学国家重点实验室_环境地球化学国家重点实验室_期刊论文
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Recommended Citation GB/T 7714 |
Xun Wang,Che-Jen Lin,Wei Yuan,et al. Emission-dominated gas exchange of elemental mercury vapor over natural surfaces in China[J]. Atmospheric Chemistry and Physics,2016,16(17):11125-11143.
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APA |
Xun Wang,Che-Jen Lin,Wei Yuan,Jonas Sommar,Wei Zhu,&Xinbin Feng.(2016).Emission-dominated gas exchange of elemental mercury vapor over natural surfaces in China.Atmospheric Chemistry and Physics,16(17),11125-11143.
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MLA |
Xun Wang,et al."Emission-dominated gas exchange of elemental mercury vapor over natural surfaces in China".Atmospheric Chemistry and Physics 16.17(2016):11125-11143.
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