HR: 10:50h
AN: C32A-03    [Abstracts]
TI: Tundra Soil-Water Content and Temperature Behavior and Implications for Winter Tundra Travel
AU: * Lilly, M R
EM: mlilly@gwscientific.com
AF: Geo-Watersheds Scientific, PO Box 81538, Fairbanks, AK 99708, United States
AU: Paetzold, R
EM: rpaetzold@gwscientific.com
AF: Geo-Watersheds Scientific, 2915 Cortez Court, College Station, Tx 77845, United States
AU: Kane, D L
EM: ffdlk@uaf.edu
AF: Water and Environmental Research Center, Univ. of Alaska Fairbanks, Duckering Building, Fairbanks, AK 99775, United States
AB: Unfrozen soil-water content was monitored in the upper meter of tundra soils, using TDR sensors at several locations on the North Slope of Alaska and in the Brooks Range foothills. In addition, soil temperature was monitored to a depth of 1.5 m at these locations using thermistors. Particular attention was paid to soil water and temperature behavior during freezing and thawing conditions. The upper organic layer of soil often exhibited very wet conditions and showed much greater temporal variability than the lower mineral soil layers. Permafrost acts as a barrier to water flow, so the soils usually are wet as they thaw in the spring. Boundaries between soil layers usually are very irregular and the soil materials are mixed due to churning from frost heaving. Soil-water content sensors integrate soil-water content over a relatively large volume compared to the essentially point measurements of the thermistors used to measure soil temperature. Anyone who has worked in the field knows how difficult it is to place sensors at an exact depth. Soil-surface roughness and vegetation under tundra conditions make accurate placement almost impossible. Minor discrepancies between soil-water freezing and thawing behavior should be expected. However, an overall picture of the annual soil-freezing processes still can be described by these matched sets of sensor observations. In addition to this data, general meteorological and snow depth data is collected. Results of this study may be useful in improving tundra travel guidelines. Currently, tundra travel is allowed if the soil temperature in the upper 30 cm of soil is colder than -5C. Soil water content and resulting ice bonding in the soil matrix does impact soil properties and the resulting impacts of tundra travel.
DE: 0702 Permafrost (0475)
DE: 0704 Seasonally frozen ground
DE: 0706 Active layer
DE: 0718 Tundra (9315)
DE: 0768 Thermal regime
SC: Cryosphere [C]
MN: 2007 Fall Meeting