Proceedings of the Western Snow Conference, Bend, OR 1996.
Mark Rikkers
Mark W. Williams
Richard Sommerfeld
Department of Geography and
Institute of Arctic and Alpine Research
University of Colorado
Boulder, Colorado 80309
Department of Geography and
Institute of Arctic and Alpine Research
University of Colorado
Boulder, Colorado 80309
US Forest Service
Rocky Mountain Forest and Range Experimental Station
Fort Collins, CO
Abstract:
We evaluated the spatial variance of snowmelt discharge
during the 1995 melt season.
We tested two hypotheses at Niwot Ridge,
a continental alpine site located in the
Colorado Front Range at an elevation of 3500m:
1) meltwater discharge through
snow is positively correlated at the scale of
approximately 5m,
and 2) this characteristic
lag distance will increase with time throughout the snowmelt season.
In 1994, 16 small snowmelt lysimeters (each 0.2 m2 in area)
were placed in a circular array with a 5m radius;
lysimeters were separated by a distance of 2m along the
circumference of the circle and drained by gravity into
dedicated tipping buckets housed in a subnivean laboratory.
The spatial variability in meltwater flux was large,
with three tipping buckets
over-topped during most of the snowmelt season,
three tipping buckets receiving less
than 5% of measured snow-water equivalence (SWE),
and the remainder of the lysimeters
showing a strong diurnal hydrograph.
Not all hydrographs returned to near zero at night,
in part because of a positive sensible heat flux.
Analysis of the spatial variability of meltwater flux using
geostatistics show positive correlations at distances of less
than 6.5m for the entire snowmelt cycle.
This characteristic distance increased throughout
most of the snowmelt season,
from 2m at the beginning of melt to 10m at the end of the season.