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PROGRESS SUMMARY
We have continued our meteorological and hydrologic data
collection in support of our process-oriented research. The six
years of data collected to date is unique in its scope and
continuity in a North Hemisphere Arctic setting. This valuable
data base has allowed us to further our understanding of the
interconnections and interactions between the atmosphere/
hydrosphere/biosphere/lithosphere. The increased understanding
of the heat and mass transfer processes has allowed us to
increase our model-oriented research efforts.
Spring snowmelt on the North Slope of Alaska is the dominant
hydrologic event of the year. (Kane et al., 1990a). This event
provides most of the moisture for use by vegetation in the spring
and early summer period. The mechanisms and timing of snowmelt
are important factors in predicting runoff, the migrations of
birds and large mammals and the diversity of plant communities.
It is important globally due to the radical and abrupt change in
the surface energy balance over vast areas.
We were able to explore the trends and differences in the
snowmelt process along a transect from the Brooks Range to the
Arctic Coastal plain. Snowpack ablation was monitored at three
sites. These data were analyzed along with meteorologic data at
each site. The initiation of ablation was site specific being
largely controlled by the complementary addition of energy from
radiation and sensible heat flux. Although the research sites
were only 115 km apart, the rates and mechanisms of snowmelt
varied greatly (Figure 1.). Usually, snowmelt begins at the mid-
elevations in the foothills and progresses northerly toward the
coast and southerly to the mountains. In the mere southerly
areas snowmelt progressed much faster and was more influenced by
sensible heat advected from areas south of the Brooks Range
(Table 1.). In contrast, snowmelt in the more northerly areas
was slower and the controlled by net radiation. (Hinzman et al.,
1990b)
The hydrologic cycle of an arctic watershed is dominated by such
physical elements as snow, ice, permafrost, seasonally frozen
soils, wide fluctuations in surface energy balance and phase
change of snow and ice to water. At Imnavait basin, snow
accumulation begins in September or early October and maximum
snowpack water equivalent is reached just prior to the onset of
ablation in mid May. No significant mid winter melt occurs in
this basin. Considerable snowfall redistribution by wind to
depressions and valley bottoms is evident (Figure 2). This is
hydrologically important as it places the snow close to runoff
5
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Annual dynamics within the active layer, report, January 1, 1991; United States. (https://digital.library.unt.edu/ark:/67531/metadc1074822/m1/2/: accessed July 16, 2024), University of North Texas Libraries, UNT Digital Library, https://digital.library.unt.edu; crediting UNT Libraries Government Documents Department.