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首页> 外文期刊>Atmospheric chemistry and physics >Air–surface exchange of gaseous mercury over permafrost soil: an investigation at a high-altitude (4700?m?a.s.l.) and remote site in the central Qinghai–Tibet Plateau
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Air–surface exchange of gaseous mercury over permafrost soil: an investigation at a high-altitude (4700?m?a.s.l.) and remote site in the central Qinghai–Tibet Plateau

机译：多年冻土土壤上气态汞的空气表面交换：在青藏高原中部高海拔地区（4700？m？a.s.l。）和偏远地区的一项调查

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The pattern of air–surface gaseous mercury (mainly Hg(0)) exchange in the Qinghai–Tibet Plateau (QTP) may be unique because this region is characterized by low temperature, great temperature variation, intensive solar radiation, and pronounced freeze–thaw process of permafrost soils. However, the air–surface Hg(0) flux in the QTP is poorly investigated. In this study, we performed field measurements and controlled field experiments with dynamic flux chambers technique to examine the flux, temporal variation and influencing factors of air–surface Hg(0) exchange at a high-altitude (4700?m?a.s.l.) and remote site in the central QTP. The results of field measurements showed that surface soils were the net emission source of Hg(0) in the entire study (2.86?ng?msup?2/sup?hsup?1/sup or 25.05?μg?msup?2/sup?yrsup?1/sup). Hg(0) flux showed remarkable seasonality with net high emission in the warm campaigns (June 2014: 4.95?ng?msup?2/sup?hsup?1/sup; September?2014: 5.16?ng?msup?2/sup?hsup?1/sup; and May–June?2015: 1.95?ng?msup?2/sup?hsup?1/sup) and net low deposition in the winter campaign (December?2014: ?0.62?ng?msup?2/sup?hsup?1/sup) and also showed a diurnal pattern with emission in the daytime and deposition in nighttime, especially on days without precipitation. Rainfall events on the dry soils induced a large and immediate increase in Hg(0) emission. Snowfall events did not induce the pulse of Hg(0) emission, but snowmelt resulted in the immediate increase in Hg(0) emission. Daily Hg(0) fluxes on rainy or snowy days were higher than those of days without precipitation. Controlled field experiments suggested that water addition to dry soils significantly increased Hg(0) emission both on short (minutes) and relatively long (hours) timescales, and they also showed that UV radiation was primarily attributed to Hg(0) emission in the daytime. Our findings imply that a warm climate and environmental change could facilitate Hg release from the permafrost terrestrial ecosystem in the QTP.
机译：青藏高原（QTP）的空气表面气态汞（主要为Hg（0））交换的模式可能是独特的，因为该地区的特点是温度低，温度变化大，强烈的太阳辐射以及明显的冻融多年冻土的过程。但是，对QTP中的空气表面Hg（0）通量的研究很少。在这项研究中，我们使用动态通量室技术进行了现场测量和受控现场实验，以检查高海拔（4700？m？asl）和偏远地区空气表面Hg（0）交换的通量，时间变化和影响因素站点在中央QTP中。现场测量结果表明，在整个研究中，表层土壤是Hg（0）的净排放源（2.86？ng？m ？2 ？h ？1 或25.05？gg？m ？2 ？yr ？1 ）。 Hg（0）通量表现出明显的季节性，在温暖的运动中呈高净排放（2014年6月：4.95？ng？m ？2 ？h ？1 ; 2014年9月： 5.16？ng？m ？2 ？h ？1 ;以及2015年5月至6月：1.95？ng？m ？2 ？h < sup>？1 ）和冬季运动的净低沉积（2014年12月：？0.62？ng？m ？2 ？h ？1 ）和白天也有昼间排放，夜间有沉积，特别是在没有降水的日子。干燥土壤上的降雨事件导致Hg（0）排放量大量增加并立即增加。降雪事件并未诱发Hg（0）排放的脉冲，但融雪导致Hg（0）排放的立即增加。雨天或下雪天的日汞（0）通量高于没有降水的日子。对照田间试验表明，在短（分钟）和相对长（小时）的时间尺度上，向干燥土壤中添加水会显着增加Hg（0）的排放，而且他们还表明，紫外线辐射主要归因于白天的Hg（0）排放。我们的发现表明，温暖的气候和环境变化可以促进QTP中永久冻土陆地生态系统中的Hg释放。

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