HR: 0800h
AN: C31A-1109    [Abstracts]
TI: Physical Impacts and Hydrological Model Simulations of a Tundra Watershed Affected by Fire, Seward Peninsula, Alaska
AU: * Liljedahl, A K
EM: ftakl@uaf.edu
AF: Water and Environmental Research Center Institute of Northern Engineering, University of Alaska, Fairbanks PO Box 755860, Fairbanks, AK 99775 United States
AU: Hinzman, L D
EM: ffldh@uaf.edu
AF: Water and Environmental Research Center Institute of Northern Engineering, University of Alaska, Fairbanks PO Box 755860, Fairbanks, AK 99775 United States
AU: Busey, B
EM: fnrcb1@uaf.edu
AF: Water and Environmental Research Center Institute of Northern Engineering, University of Alaska, Fairbanks PO Box 755860, Fairbanks, AK 99775 United States
AU: Yoshikawa, K
EM: ffky@uaf.edu
AF: Water and Environmental Research Center Institute of Northern Engineering, University of Alaska, Fairbanks PO Box 755860, Fairbanks, AK 99775 United States
AB: A warmer climate in the arctic region is shown to increase the frequency and severity of fires. An investigation of the effects of a fire on a tundra environment can result in a better understanding of the impact a warming climate and its secondary effects on the arctic ecosystem and its morphology, where the presence of permafrost is of vital importance in shaping the abiotic and biotic regime. The aims of the study was to investigate short-term hydrological and thermal changes at a tussock tundra basin caused by fire and apply observations into a spatially distributed computer model, TopoFlow, to simulate post-fire hydrological dynamics. Niagara Creek (6.5km²), situated at central Seward Peninsula, Northwestern Alaska, was affected by a severe burn August 2002. Field data was acquired before and after the fire at a fixed location and showed an increased average annual soil temperature the second year following the fire of 1.9°C to 2.6°C throughout the soil profile down to the observed depth of 1m, which also stated higher averages than the previous year. A doubled active layer depth was found year 2003, indicating a continuing increase 2004. The noon radiation efficiency ratio increased with 6% during June and July 2004 compared to pre-fire observations. Efficiency ratio of emitted noon long wave radiation increased with 12%. Near surface organic soils display enhanced post-fire soil moisture levels, close to saturation, throughout the thawed season. Thermokarst formation and severe erosion and occurred along Niagara Creek streambed after the fire. Post-fire hydrograph model simulations do not exhibit a large difference from the calibrated curves, with only slightly higher peak flows. Evapotranspirative water losses are reduced during post-fire simulations, while no clear change in recession periods after rainstorm events was found.
DE: 0702 Permafrost (0475)
DE: 0706 Active layer
DE: 0768 Thermal regime
DE: 0798 Modeling
DE: 1225 Global change from geodesy (1222, 1622, 1630, 1641, 1645, 4556)
SC: Cryosphere [C]
MN: Fall Meeting 2005