HR: 11:50h
AN: C32A-07    [Abstracts]
TI: Thaw-Subsidence Measurements in the Circumpolar Active Layer Monitoring (CALM) Program
AU: * Nelson, F E
EM: fnelson@udel.edu
AF: University of Delaware, Department of Geography, Newark, DE 19716, United States
AU: Shiklomanov, N I
EM: shiklom@udel.edu
AF: University of Delaware, Department of Geography, Newark, DE 19716, United States
AU: Streletskiy, D A
EM: strelets@udel.edu
AF: University of Delaware, Department of Geography, Newark, DE 19716, United States
AU: Little, J D
EM: jlittle@monroecc.edu
AF: University of Delaware, Department of Geography, Newark, DE 19716, United States
AU: Maxhitova, G G
EM: galina_m@ib.komisc.ru
AF: Komi Science Centre, Russian Academy of Sciences, Syktyvkar, 167982, Russian Federation
AU: Hinkel, K M
EM: kenneth.hinkel@uc.edu
AF: University of Cincinnati, Department of Geography, Cincinnati, OH 45221, United States
AB: Vertical movement of the ground surface due to frost heave and thaw subsidence is a common phenomenon in permafrost regions. The magnitude of this movement varies both temporally and spatially, owing to interannual climatic variability at the ground surface and to local variations of soil moisture. Because measurements at point locations made using frost/thaw tubes at CALM sites during the 1990s indicated that penetration of thaw into the ice-rich transient layer may not be reflected in records of active-layer thickness, spatial sampling experiments were initiated early in this decade at several sites in Alaska and Russia. Differential Global Positioning Systems (DGPS) technology was employed at sites in the northern Brooks Range Foothills and on the Arctic Coastal Plain of northern Alaska. Traditional theodolite survey methods were used at sites in the European Russian Arctic. The resulting heave/subsidence records, in conjunction with temperature and active-layer measurements, were used to evaluate regional and site-specific factors affecting the spatial and temporal variability of frost heave and subsidence. Heave and settlement show patterns of spatial variation similar to those of active-layer thickness (ALT). Results from all locations indicate a monotonic increase in thaw penetration into the upper ice-rich permafrost during the period of observation. The CALM II (2004-09) measurement protocol accommodates long- term subsidence measurements, and instrumentation is being developed for deployment at most CALM observatories.
DE: 0702 Permafrost (0475)
DE: 0706 Active layer
DE: 0708 Thermokarst
SC: Cryosphere [C]
MN: 2007 Fall Meeting