title: Thunderstorms Increase Mercury Wet Deposition.
abstract: Mercury (Hg) wet deposition, transfer from the atmosphere to Earth's surface by precipitation, in the United States is highest in locations and seasons with frequent deep convective thunderstorms, but it has never been demonstrated whether the connection is causal or simple coincidence. We use rainwater samples from over 800 individual precipitation events to show that thunderstorms increase Hg concentrations by 50% relative to weak convective or stratiform events of equal precipitation depth. Radar and satellite observations reveal that strong convection reaching the upper troposphere (where high atmospheric concentrations of soluble, oxidized mercury species (Hg(II)) are known to reside) produces the highest Hg concentrations in rain. As a result, precipitation meteorology, especially thunderstorm frequency and total rainfall, explains differences in Hg deposition between study sites located in the eastern United States. Assessing the fate of atmospheric mercury thus requires bridging the scales of global transport and convective precipitation.
authors.affiliation: Department of Earth, Ocean, and Atmospheric Science, Florida State University , Tallahassee, Florida 32306, United States.
authors.forename: Christopher D
authors.initials: CD
authors.lastname: Holmes
authors.affiliation: Department of Earth, Ocean, and Atmospheric Science, Florida State University , Tallahassee, Florida 32306, United States.
authors.forename: Nishanth P
authors.initials: NP
authors.lastname: Krishnamurthy
authors.affiliation: Center for Environmental Diagnostics and Bioremediation, University of West Florida , Pensacola, Florida 32514, United States.
authors.forename: Jane M
authors.initials: JM
authors.lastname: Caffrey
authors.affiliation: Department of Earth, Ocean, and Atmospheric Science, Florida State University , Tallahassee, Florida 32306, United States.
authors.forename: William M
authors.initials: WM
authors.lastname: Landing
authors.affiliation: Atmospheric Research & Analysis, Inc. , Cary, North Carolina 27513, United States.
authors.forename: Eric S
authors.initials: ES
authors.lastname: Edgerton
authors.affiliation: National Centers for Environmental Information, National Oceanic and Atmospheric Administration , Asheville, North Carolina 28801, United States.
authors.forename: Kenneth R
authors.initials: KR
authors.lastname: Knapp
authors.affiliation: Department of Atmospheric Science, University of Alabama , Huntsville, Alabama 35805, United States.
authors.forename: Udaysankar S
authors.initials: US
authors.lastname: Nair
mesh_terms: D000393:Air Pollutants; D001272:Atmosphere; D004784:Environmental Monitoring; D008628:Mercury; D011891:Rain; D012621:Seasons; D014481:United States
chemical_list: D000393:Air Pollutants; D008628:Mercury