| Autor: |
Holmes CD; Department of Earth, Ocean, and Atmospheric Science, Florida State University , Tallahassee, Florida 32306, United States., Krishnamurthy NP; Department of Earth, Ocean, and Atmospheric Science, Florida State University , Tallahassee, Florida 32306, United States., Caffrey JM; Center for Environmental Diagnostics and Bioremediation, University of West Florida , Pensacola, Florida 32514, United States., Landing WM; Department of Earth, Ocean, and Atmospheric Science, Florida State University , Tallahassee, Florida 32306, United States., Edgerton ES; Atmospheric Research & Analysis, Inc. , Cary, North Carolina 27513, United States., Knapp KR; National Centers for Environmental Information, National Oceanic and Atmospheric Administration , Asheville, North Carolina 28801, United States., Nair US; Department of Atmospheric Science, University of Alabama , Huntsville, Alabama 35805, United States. |
| Abstrakt: |
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. |
