Department of Atmospheric Science, University of Alabama in Huntsville , Huntsville, Alabama 35806, United States.
Department of Earth, Ocean and Atmospheric Science, Florida State University , Tallahassee, Florida 32306, United States.
Environ Sci Technol. 2017 Mar 7;51(5):2628-2634. doi: 10.1021/acs.est.6b04187. Epub 2017 Feb 10.
We analyze the effect of precipitation type on mercury wet deposition using a new database of individual rain events spanning the contiguous United States. Measurements from the Mercury Deposition Network (MDN) containing single rainfall events were identified and classified into six precipitation types. Mercury concentrations in surface precipitation follow a power law of precipitation depth that is modulated by precipitation system morphology. After controlling for precipitation depth, the highest mercury deposition occurs in supercell thunderstorms, with decreasing deposition in disorganized thunderstorms, quasi-linear convective systems (QLCS), extratropical cyclones, light rain, and land-falling tropical cyclones. Convective morphologies (supercells, disorganized, and QLCS) enhance wet deposition by a factor of at least 1.6 relative to nonconvective morphologies. Mercury wet deposition also varies by geographic region and season. After controlling for other factors, we find that mercury wet deposition is greater over high-elevation sites, seasonally during summer, and in convective precipitation.
我们使用一个涵盖美国大陆的新的个别降雨事件数据库，分析了降水类型对汞湿沉降的影响。从包含单个降雨事件的汞沉降网络 (MDN) 中识别并分类出六种降水类型。地表降水的汞浓度遵循降水深度的幂律，该规律受降水系统形态的调节。在控制降水深度后，超单体雷暴的汞沉积最高，非组织雷暴、准线性对流系统 (QLCS)、温带气旋、小雨和登陆热带气旋的沉积减少。对流形态（超级单体、非组织和 QLCS）相对于非对流形态增强了至少 1.6 倍的湿沉降。汞湿沉降还因地理位置和季节而异。在控制其他因素后，我们发现，高海拔地区、夏季和对流降水时的汞湿沉降更大。
