HR: 14:45h
AN: C43B-06    [Abstracts]
TI: Tracing Pollutants in Northwest Alaskan Snow
AU: * Johnston, M H
EM: merrickj@dartmouth.edu
AF: Dartmouth College, 6105 Fairchild, Hanover, NH 03755-3571 United States
AU: Feng, X
EM: xiahong.feng@dartmouth.edu
AF: Dartmouth College, 6105 Fairchild, Hanover, NH 03755-3571 United States
AU: Posmentier, E S
EM: posmentier@dartmouth.edu
AF: Dartmouth College, 6105 Fairchild, Hanover, NH 03755-3571 United States
AU: Albert, M R
EM: Mary.R.Albert@erdc.usace.army.mil
AF: Cold Regions Research and Engineering Laboratoty, 72 Lyme RD, Hanover, NH 03755 United States
AU: Weatherly, J W
EM: John.W.Weatherly@erdc.usace.army.mil
AF: Cold Regions Research and Engineering Laboratoty, 72 Lyme RD, Hanover, NH 03755 United States
AU: Sturup, S
EM: stefan.sturup@dartmouth.edu
AF: Dartmouth College, 6105 Fairchild, Hanover, NH 03755-3571 United States
AB: Northwest Alaska has two primary storm tracks: one coming from the South, bringing the Pacific air mass, and the other from the North bringing the Arctic air mass to the area. In general, the precipitation is cleaner in the southern source than the northern one because the latter involves the Arctic air mass contaminated by industrial pollutants from Northern Russia (AMAP Report, 2002; Pollisar et al. 1998). As a result, the storm tracks may significantly affect the contaminant deposition in Northwest Alaska. In spring of 2003, a sampling team traveled inland from Kotzebue towards Kobuk, completing a 400-mile loop, collecting snow samples, and interacting with the local residents about related science and cultural experiences. Along the route, nine snow pits were dug and a series of physical observations and measurements was made including temperature, snow depth, snow density, presence of ice layers, and crystal grain classes. For each identified snow layer, samples were taken for quantitative microcopy and chemical and isotopic analyses. We examined hydrogen isotopic compositions, trace metal concentrations (including Cr, Co, As, Pb, V and Cd), and the tracks of storms from surface weather maps provided by the US Navy. The winter of 2002-2003 marked an unusually mild year for Alaska. A detailed examination of 12-hour weather maps for the snow accumulation period shows that most storms were derived from the Pacific Ocean, and these storms have variable δD values, ranging from -123 to -207. Only one storm, which may be carrying pollutants from Russia was from the Bering Sea. This storm occurred during the sampling trip and only four out of nine sites were sampled. Isotopically, this storm is significantly more enriched in deuterium (-100 permil) than the other storms. We conducted a discriminant analysis separating the samples into three groups -- the Bering Sea storm, the Pacific storms with relatively low δD values, and the Pacific storms with relative high δD values. These groups have different patterns in metal variations and thus significant separations are obtained along the first canonical axis. This result suggests that the contaminant loading in snow is not only affected by the moisture source of the storm, but also by the pathway of the storm tracks.
DE: 0345 Pollution--urban and regional (0305)
DE: 1040 Isotopic composition/chemistry
DE: 1854 Precipitation (3354)
DE: 1863 Snow and ice (1827)
SC: Cryosphere [C]
MN: 2005 Joint Assembly