HR: 11:05h
AN: A12B-03    [Abstracts]
TI: Mercury deposition to snow and ice provides a link between the lower atmosphere and the cryosphere in northern Alaska
AU: * Douglas, T A
EM: Thomas.A.Douglas@erdc.usace.army.mil
AF: Cold Regions Research and Engineering Laboratory- Alaska, Building 4070, PO Box 35170, Fort Wainwright, AK 99703-0170 United States
AU: Sturm, M
EM: Matthew.Sturm@erdc.usace.army.mil
AF: Cold Regions Research and Engineering Laboratory- Alaska, Building 4070, PO Box 35170, Fort Wainwright, AK 99703-0170 United States
AU: Simpson, W R
EM: ffwrs@uaf.edu
AF: University of Alaska Fairbanks Department of Chemistry and Biochemistry and Geophysical Institute, 900 Yukon Drive, Fairbanks, AK 99775-6160 United States
AU: Alvarez-Aviles, L
EM: ftla@uaf.edu
AF: University of Alaska Fairbanks Department of Chemistry and Biochemistry and Geophysical Institute, 900 Yukon Drive, Fairbanks, AK 99775-6160 United States
AU: Blum, J D
EM: jdblum@umich.edu
AF: University of Michigan Department of Geological Sciences, 2534 CC Little Bldg 1100 North University Ave, Ann Arbor, MI 48109-1005 United States
AU: Perovich, D K
EM: Donald.K.Perovich@erdc.usace.army.mil
AF: Cold Regions Research and Engineering Laboratory- New Hampshire, 72 Lyme Road, Hanover, NH 03755 United States
AU: Keeler, G J
EM: jkeeler@umich.edu
AF: University of Michigan Air Quality Laboratory, 109 South Observatory, Ann Arbor, MI 48109 United States
AU: Lammers, A
EM: alammers@umich.edu
AF: University of Michigan Department of Geological Sciences, 2534 CC Little Bldg 1100 North University Ave, Ann Arbor, MI 48109-1005 United States
AU: Biswas, A
EM: abiswas@umich.edu
AF: University of Michigan Department of Geological Sciences, 2534 CC Little Bldg 1100 North University Ave, Ann Arbor, MI 48109-1005 United States
AB: We investigated a wide range of snow and ice forms as potential scavengers of atmospheric mercury during mercury depletion events (MDEs). Our work was part of a large campaign near Barrow, Alaska in the spring of 2005 (LEADEX-2005). Gaseous and reactive phase mercury, ozone and halogen oxide measurements were made at numerous locations along the Arctic Ocean Coast as part of the campaign and allowed us to identify when MDEs were occurring. Results from previous work implicated sea ice leads and the near shore coastal snow pack as locations where elevated mercury concentrations in frost flowers (75-185 ng/L) and surface hoar (~900 ng/L) were likely. In LEADEX-2005 the previous work was expanded by sampling snow along transects away from the lead edge and from daily sampling of diamond dust and surface snow at a site located 6 kilometers inland from the lead. Vapor condensate was also collected on chilled sample bottles hoisted above the lead on a 2 m² kite and from a 2-m high pole. We also sampled surface hoar, rime ice, wind slab, fresh snow and blowing snow near the leads. Diamond dust was collected in glass trays and rime was scraped from the leading edge of an unmanned aerial vehicle wing. Nilas and frost flowers of varying ages were collected from a boat in open water at the lead. Elevated mercury concentrations were measured in virtually every type of vapor deposited snow or ice form, including some samples that yielded concentrations well over 1000 ng/L. Our results suggest that deposition of mercury to snow and ice during MDEs is controlled by four processes: 1) scavenging during crystallization or snow fall, 2) impaction of mercury laden aerosols onto crystalline surfaces, 3) sublimation of snow and ice, and 4) condensation driven by temperature gradients. We believe these four factors combine to control elevated mercury concentrations where the lower atmosphere and cryosphere meet.
DE: 0312 Air/sea constituent fluxes (3339, 4504)
DE: 0736 Snow (1827, 1863)
DE: 0738 Ice (1863)
DE: 0750 Sea ice (4540)
DE: 3339 Ocean/atmosphere interactions (0312, 4504)
SC: Atmospheric Sciences [A]
MN: Fall Meeting 2005