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Balance, Meteorological, Ice Motion, Surface Altitude, Runoff, and
Ice Thickness Data at Gulkana Glacier, Alaska, 1995
by Rod S. March
U.S. GEOLOGICAL SURVEY
Water-Resources Investigations Report 00-4074
The 1995 measured winter snow, maximum winter snow, net, and
annual balances in the Gulkana Glacier basin were evaluated on the basis of
meteorological, hydrological, and glaciological data obtained in the basin.
Averaged over the glacier, the measured winter snow balance was 0.94 meter
on April 19, 1995, 0.6 standard deviation below the long-term average; the
maximum winter snow balance, 0.94 meter, was reached on April 25, 1995; the
net balance (from September 18, 1994 to August 29, 1995) was -0.70 meter,
0.76 standard deviation below the long-term average. The annual balance
(October 1, 1994, to September 30, 1995) was -0.86 meter. Ice-surface motion
and altitude changes measured at three index sites document seasonal ice
speed and glacier-thickness changes. Annual stream runoff was 2.05 meters
averaged over the basin, approximately equal to the long-term average.
The 1976 ice-thickness
data are reported from a single site near the highest measurement site
(180 meters thick) and from two glacier cross profiles near the
mid-glacier (270 meters thick on centerline) and low glacier (150 meters
thick on centerline) measurement sites.
A new area-altitude
distribution determined from 1993 photogrammetry is reported.
Area-averaged balances are reported from both the 1967 and 1993
area-altitude distribution so the reader may directly see the effect of
the update. Briefly, loss of ablation
area between 1967 and 1993 results in a larger weighting being applied to
data from the upper glacier site and hence, increases calculated
area-averaged balances. The balance increase is of the order of 15 percent
for net balance.
March, R. S., 2000, Mass balance, meteorological, ice motion, surface altitude,
runoff, and ice thickness data at Gulkana Glacier, Alaska, 1995 balance year: U.S. Geological Survey
Water-Resources Investigations Report 00-4074, 33 p.
[Full Report, Acrobat PDF (2.8 MB)]
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Maintainer: Rod March
Last update: Monday, December 27, 2010 05:06 PM