HR: 0800h
AN: C31A-1107    [Abstracts]
TI: Modeling non-sorted circles along low Arctic climate gradient, Dalton highway, Alaska
AU: * Nicolsky, D J
EM: ftdjn@uaf.edu
AF: Geophysical Institute, University of Alaska Fairbanks, PO Box 757320, Fairbanks, AK 99775-7320
AU: Romanovsky, V E
EM: ftver@uaf.edu
AF: Geophysical Institute, University of Alaska Fairbanks, PO Box 757320, Fairbanks, AK 99775-7320
AU: Tipenko, G S
EM: ffgst@uaf.edu
AF: Geophysical Institute, University of Alaska Fairbanks, PO Box 757320, Fairbanks, AK 99775-7320
AU: Walker, D A
EM: ffdaw@uaf.edu
AF: Institute of Arctic Biology, University of Alaska Fairbanks, PO Box 757000, Fairbanks, AK 99775-7000
AB: This research investigates cryoturbation processes in the Arctic tundra, and mechanisms that cause differential frost heave in the active layer. The project explores the influence of seasonal freeze/thaw cycles on the dynamics of frost boils north of the Alaska's Brook Range. The main question to be addressed is, "How changes in surface conditions such as vegetation, snow cover and climate affect the seasonal dynamics of water and heat within frost-boil systems?" A coupled thermo-mechanical model of the frost boil phenomena based on principles of non-smooth thermo-mechanics is presented. The soil is treated as a heterogeneous fully saturated mixture of ice, water and soil particles, which obeys laws of elasticity for slow deformations in a porous media. The pore water migration towards the freezing zone and its consequent freezing are the main driving forces of the soil deformation. The model includes the heat and mass conservation laws, continuity equation, the Clapeyron's equation, and an empirical formula, which relates unfrozen water content to temperature. We applied this model to investigate the sensitivity of a predicted differential frost heave, to thermo-rheological properties of the soil and other physical parameters. The model shows that the soil texture plays the decisive role in creating the differential frost heave. Modeling of frost-boil systems along the Arctic gradient and reaction of them to changes in climate, in the active layer depth and in vegetation cover is performed by specifying boundary conditions and soil properties. Using this model we explore interaction between vegetation cover and thermo-mechanical processes at several sites along the Dalton highway in the Arctic tundra.
DE: 0704 Seasonally frozen ground
DE: 0766 Thermodynamics (1011, 3611, 8411)
DE: 0798 Modeling
SC: Cryosphere [C]
MN: Fall Meeting 2005