HR: 0800h
AN: C41A-0175    [Abstracts]
TI: Remote Sensing of Spring Streams on Alaska's North Slope
AU: * Balser, A W
EM: fnawb@uaf.edu
AF: Institute of Arctic Biology, University of Alaska Fairbanks, IAB, 311 Irving I University of Alaska Fairbanks, Fairbanks, AK 99775 United States
AU: Huryn, A D
EM: huryn@bama.ua.edu
AF: Aquatic Biology Program, University of Alabama, A122 Bevill Building, 7th Ave. University of Alabama, Tuscaloosa, AL 35487 United States
AB: Spring-fed headwater streams are thought to dramatically affect local aquatic food-web dynamics by providing continual ice-free refugia for species unable to tolerate freezing. Accurate locations of these streams on Alaska's North Slope are needed to investigate associated hypotheses. Thermal springs on Alaska's North Slope are spread over vast, roadless areas and are difficult to identify in summer by aerial survey. Pre-existing data on spring locations are incomplete, largely anecdotal and of insufficient accuracy for use in field sampling. Satellite remote sensing provides capabilities for measuring, monitoring and querying large tracts of remote landscape in an efficient, synoptic manner. Landsat Enhanced Thematic Mapper(ETM) imagery was used to reconnoiter a region of the North Slope using winter scenes, when the contrast between ambient conditions and the springs' thermal signal is easiest to detect. Scenes from February 9, 2002 were selected from the available archive based on cloud cover ($<$10%), and the lowest ambient temperature for dates with adequate archived imagery. Analytical methods were two tiered. A manual examination and interpretation of the imagery detected obvious linear features of relatively high temperature in logical locations for springs. A second examination, using masking and ratio techniques with tabular query, suppressed confounding factors and identified a second set of likely thermal spring locations. A subset coordinate list of candidate sites was developed from these findings, and drove sampling/ground truthing activity in the summer of 2004. All sites visited were confirmed springs and are part of ongoing aquatic food-web research based at Toolik Field Station.
UR: http://www.uaf.edu/toolik/gis/NABS_poster.pdf
DE: 9315 Arctic region
DE: 8135 Hydrothermal systems (8424)
DE: 4894 Instruments and techniques
DE: 4804 Benthic processes/benthos
DE: 1829 Groundwater hydrology
SC: Cryosphere [C]
MN: 2004 AGU Fall Meeting