HR: 0800h
AN: C41A-0056    [Abstracts]
TI: A Laboratory Scale Study of the Fluid and Energy Dynamics in Non-sorted Circle Systems of Alaska
AU: Misra, D
EM: debu.misra@uaf.edu
AF: University of Alaska Fairbanks, Department of Mining and Geological Engineering, College of Engineering and Mines, PO Box 755800, Fairbanks, AK 99775, United States
AU: * Daanen, R
EM: ffrd@uaf.edu
AF: University of Alaska Fairbanks, Geophysical Institute, 903 Koyukuk Drive, Fairbanks, AK 99775, United States
AU: Samuel, R A
EM: fsras25@uaf.edu
AF: University of Alaska Fairbanks, Department of Mining and Geological Engineering, College of Engineering and Mines, PO Box 755800, Fairbanks, AK 99775, United States
AB: Non-sorted circle ecosystems are naturally stable and abundant ecosystems throughout the Arctic tundra. These are formed by processes of differential frost heave and are an important component of the water cycle in tundra regions. Even though the soil surface is basically bare, these systems are very stable. The stability of the system equilibrium and associated water and energy fluxes is, however, poorly understood. Water and ice are critical to non-sorted circle formation and interact in complex ways with the surrounding vegetation, soils, atmosphere and hydrological systems. Climate warming is expected to significantly affect such complex interaction in these ecosystems. It is also not clear how these systems will react to a larger shift in the perturbation of the soil surface. The objective of this study is to develop a laboratory scale model using soil from a non-sorted circle ecosystem to understand the effects of differential freezing on water and energy fluxes across its boundaries due to variations in temperature and insulation. We have generated a heave pattern using an insulation pattern that is similar to what is observed in the field using this laboratory setup. We have identified that preferential ice accumulation occurs underneath the soil and is sensitive to the freezing temperature and the amount of insulation. The amount of heave cannot be described by the expansion of water alone, secondary processes of water movement are very important in frost susceptible soils like the one used in the experiment. Since non- sorted circle systems are ubiquitous to Arctic Alaska, our research focus is expected to complement the existing knowledge base in pan-Arctic studies by improving the understanding of the ecosystem functioning, structure and stability at the regional scale.
DE: 0702 Permafrost (0475)
DE: 0710 Periglacial processes
DE: 0720 Glaciers
DE: 0774 Dynamics
DE: 1824 Geomorphology: general (1625)
SC: Cryosphere [C]
MN: 2007 Fall Meeting