HR: 1340h
AN: A23B-0778    [Abstracts]
TI: Coupled Physical and Chemical Study of the Subarctic Snowpack: Feedback of Metamorphic Intensity on Climate Change
AU: Domine, F
EM: florent@lgge.obs.ujf-grenoble.fr
AF: Geophysical Institute, University of Alaska Fairbanks, 903 Koyukuk Drive, P.O. Box 757320, Fairbanks, AK 99775-7320 United States
AU: Domine, F
EM: florent@lgge.obs.ujf-grenoble.fr
AF: International Arctic Research Center, University of Alaska Fairbanks, 930 Koyukuk Drive, P.O. Box 757340, Fairbanks, AK 99775-7340 United States
AU: Domine, F
EM: florent@lgge.obs.ujf-grenoble.fr
AF: CNRS, Glaciology Laboratory, 54, rue Moliere, B.P. 96, Saint-Martin d'Heres, 38402 France
AU: * Taillandier, A
AF: Geophysical Institute, University of Alaska Fairbanks, 903 Koyukuk Drive, P.O. Box 757320, Fairbanks, AK 99775-7320 United States
AU: * Taillandier, A
AF: International Arctic Research Center, University of Alaska Fairbanks, 930 Koyukuk Drive, P.O. Box 757340, Fairbanks, AK 99775-7340 United States
AU: * Taillandier, A
AF: CNRS, Glaciology Laboratory, 54, rue Moliere, B.P. 96, Saint-Martin d'Heres, 38402 France
AU: Alvarez-Aviles, L
AF: Geophysical Institute, University of Alaska Fairbanks, 903 Koyukuk Drive, P.O. Box 757320, Fairbanks, AK 99775-7320 United States
AU: Alvarez-Aviles, L
AF: Department of Chemistry, University of Alaska Fairbanks, 900 Yukon Drive, Fairbanks, AK 99775-6160 United States
AU: Simpson, W
AF: Geophysical Institute, University of Alaska Fairbanks, 903 Koyukuk Drive, P.O. Box 757320, Fairbanks, AK 99775-7320 United States
AU: Simpson, W
AF: Department of Chemistry, University of Alaska Fairbanks, 900 Yukon Drive, Fairbanks, AK 99775-6160 United States
AU: Houdier, S
AF: CNRS, Glaciology Laboratory, 54, rue Moliere, B.P. 96, Saint-Martin d'Heres, 38402 France
AU: Douglas, T
AF: Cold Regions Research and Engineering Laboratory, P.O. Box 35170, Fort Wainwright, AK 99703-0170 United States
AU: Sturm, M
AF: Cold Regions Research and Engineering Laboratory, P.O. Box 35170, Fort Wainwright, AK 99703-0170 United States
AU: Stolzberg, R
AF: Department of Chemistry, University of Alaska Fairbanks, 900 Yukon Drive, Fairbanks, AK 99775-6160 United States
AB: Temperature gradients in snowpacks induce metamorphism via sublimation/condensation cycles that physically alter snow crystals and promote the release or uptake of atmospheric trace gases. A change in the intensity of metamorphism caused by global warming will thus modify both the physics of the snowpack (albedo, heat transfer, permeability) and its chemical exchanges with the atmosphere. These modifications could exert strong feedbacks on global change. To identify these feedbacks, we performed a coupled study of snowpack physics and chemistry during an entire winter in Fairbanks, central Alaska, where cold ambient temperatures and a thin snowpack generate an intense metamorphism. We also monitored the evolution of the same snowpack subjected to low grade metamorphism by letting snow accumulate on tables, under which air circulation prevented the establishment of any significant temperature gradient. Variables measured regularly included: air and snow temperatures, the density, specific surface area and permeability of snow, crystal sizes and shapes and concentrations of major ions, aldehydes and O and D isotopes. The evolution of the natural snowpack is markedly different from that on tables. Snow permeability is about 20 times greater, density is lower and the specific surface area decreases faster with time in the natural snowpack. This results in a lower albedo, stronger soil/atmosphere gas exchanges and different soil/atmosphere heat transfers. The high grade metamorphism in the natural snowpack also leads to enhanced release of trace gases from the snowpack to the atmosphere, as observed for formaldehyde. The effects of a changing climate on snow physics and chemistry will be considered in light of the extensive dataset obtained during the winter of 2003-2004. The following feedbacks will be discussed: rate of decrease of SSA and snow albedo, permeability and heat transfer, input to the atmosphere and atmospheric chemistry-climate feedbacks, release of nutrients and pollutants to the biosphere after melting.
DE: 9315 Arctic region
DE: 1610 Atmosphere (0315, 0325)
DE: 0322 Constituent sources and sinks
DE: 0365 Troposphere--composition and chemistry
SC: Atmospheric Sciences [A]
MN: 2004 AGU Fall Meeting