HR: 0800h
AN: C41A-0195    [Abstracts]
TI: Snowmelt Hydrology of a Headwater Arctic Basin Revisited
AU: * Berezovskaya, S
EM: ffslb2@uaf.edu
AF: University of Alaska Fairbanks, Water and Environmental Research Center, Fairbanks, AK 99775 United States
AU: Kane, D L
EM: ffdlk@uaf.edu
AF: University of Alaska Fairbanks, Water and Environmental Research Center, Fairbanks, AK 99775 United States
AU: Hinzman, L D
EM: ffldh@uaf.edu
AF: University of Alaska Fairbanks, Water and Environmental Research Center, Fairbanks, AK 99775 United States
AB: Nine months of snow accumulation in the Alaskan Arctic guarantees that the snowmelt event will be a significant annual hydrologic event. These breakup floods constitute a majority of the maximum annual floods, although rainfall floods will generate the peak floods of record for small to intermediate sized headwater catchments. A paper published after the initial five years of study (1985-1989) concluded that redistribution of the snowpack by wind, direction of the prevailing winds and lack of subsurface storage produced runoff responses that resulted in significantly high values. The average maximum snowpack leaving the Imnavait Creek catchment as runoff immediately following ablation ranged from 0.50 to 0.66. What have we learned from 15 more years of data collection for this small headwater basin? First, our initial conclusions are still true. Further, this additional data allows us to re-examine the annual variability of the snow water equivalent (SWE) and timing of ablation, and the hydrologic runoff response. Over the 20-year period of record, the SWE has ranged from 69 mm to over 185 mm (standard deviation of 33 mm) and the window of ablation is from late April to June 10, or about six weeks. Both of these ranges are much greater than those observed during the first 5 years. Also, the runoff ratio over this period varies from 0.44 to 0.80 with a standard deviation of 0.11. This recent increase in variation may or may not be due to a changing climate. The subtle impact of a warming climate may be lost in the large inter-annual variation of hydrologic variables; however this reanalysis does permit better quantification of the natural variability and the 20-year data set is now beginning to provide the basis for evaluating longer-term trends.
DE: 1821 Floods
DE: 1823 Frozen ground
DE: 1833 Hydroclimatology
DE: 1836 Hydrologic budget (1655)
DE: 1863 Snow and ice (1827)
SC: Cryosphere [C]
MN: 2004 AGU Fall Meeting