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TitleMeteorological snow chemistry relationships at Divide Site, St. Elias Mountains, Yukon Territory
AuthorVogan, N W; Kreutz, K J; Wake, C P; Zdanowicz, C MORCID logo; Copland, L; Fisher, D; Osterberg, E; Wanamaker, A; Yalcin, K
SourceEos, Transactions of the American Geophysical Union vol. 87, no. 52, 2006, 1 pages
LinksOnline - En ligne
Alt SeriesEarth Sciences Sector, Contribution Series 20080617
MeetingAmerican Geophysical Union, Fall meeting; San Francisco; US; December 11-15, 2006
Mediapaper; on-line; digital
AreaSt. Elias Mountains; Mount Logan; Eclipse Icefield
Lat/Long WENS-142.0000 -140.0000 61.0000 60.0000
Subjectssurficial geology/geomorphology; ice; ice conditions; snow; precipitation; cores; core analysis; atmospheric geochemistry; sediment transport; transport mechanisms; transportation
Released2006 01 01
AbstractA new ice core (343 m) was collected from the Eclipse Icefield (~30 km northeast of the Logan Massif, 3017 masl) in the St. Elias Mountains in 2001-02. Previous work on snow samples and an ice core recovered in 1980 from Mt. Logan (5345 masl) has shown that major discontinuities in the variation of the water stable isotope ratios exist with altitude, which are believed to be derived from a multilayered atmosphere during precipitation events on high altitude glacier sites. To properly interpret the glaciochemical records developed from the new Eclipse Icefield ice cores, calibration of snow properties with meteorological data (temperature, precipitation, and sea level pressure) is critical. At the Divide Site (2800 masl), two automatic weather stations (AWS) have been operating since 2002, collecting snow depth as well as standard meteorological data. Based on the AWS data from 2002-2005, the site has a mean annual temperature of -9°C with an average wind speed of 21 km/hr and a mean atmospheric pressure of 726 mb. The winter accumulation seasons (August-April) of 2002-03, 2003-04, 2005-06 result in ~4m of snow (~2m w.e.) with a net surface height change of ~2m over the balanced year (August-August) thereby allowing discrete subannual isotopic records. Accumulating snow from 2002-03 and 2003-04 has an average isotopic composition of -186(permil) (SMOW) deltaD and -24(permil) (SMOW) delta18O. We will present a detailed analysis of the accumulation record at the site from 2003 to 2006 in order to identify the individual snowfall events. We will discuss the changes in the isotopic composition between these snowfall events and determine the relative control that variability in the local meteorological conditions at the time of precipitation and broader scale changes in atmospheric circulation and moisture transport have on stable water isotopes in precipitation in the St. Elias Mountains.

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