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JOURNAL OF GEOPHYSICAL RESEARCH,
VOL. 113,
F02019,
doi:10.1029/2007JF000850,
2008
Distributed energy balance modeling of South Cascade Glacier, Washington and assessment of model uncertainty
Faron S. Anslow
Department of Geosciences, Oregon State University, Corvallis, Oregon, USA
Steven Hostetler
United States Geological Survey, Department of Geosciences, Oregon State University, Corvallis, Oregon, USA
William R. Bidlake
United States, Geological Survey, Washington Water Science Center, Tacoma, Washington, USA
Peter U. Clark
Department of Geosciences, Oregon State University, Corvallis, Oregon, USA
Abstract
We have developed a physically based, distributed surface energy balance model to simulate glacier mass balance under meteorological
and climatological forcing. Here we apply the model to estimate summer ablation on South Cascade Glacier, Washington, for
the 2004 and 2005 mass balance seasons. To arrive at optimal mass balance simulations, we investigate and quantify model uncertainty
associated with selecting from a range of physical parameter values that are not commonly measured in glaciological mass balance
field studies. We optimize the performance of the model by varying values for atmospheric transmissivity, the albedo of surrounding
topography, precipitation-elevation lapse rate, surface roughness for turbulent exchange of momentum, and snow albedo aging
coefficient. Of these the snow aging parameter and precipitation lapse rates have the greatest influence on the modeled ablation.
We examined model sensitivity to varying parameters by performing an additional 103 realizations with parameters randomly chosen over a ±5% range centered about the optimum values. The best fit suite of model
parameters yielded a net balance of −1.69 ± 0.38 m water equivalent (WE) for the 2004 water year and −2.10 ± 0.30 m WE up
to 11 September 2005. The 2004 result is within 3% of the measured value. These simulations account for 91% and 93% of the
variance in measured ablation for the respective years.
Received 18
June
2007;
accepted 20
February
2008;
published 31
May
2008.
Keywords: glaciology;
modeling;
climate.
Index Terms: 0764 Cryosphere: Energy balance; 0798 Cryosphere: Modeling; 0762 Cryosphere: Mass balance (1218, 1223); 1873 Hydrology: Uncertainty assessment (3275).
Read Full Article (file size: 1233174 bytes) Cited by
Citation: Anslow, F. S., S. Hostetler, W. R. Bidlake, and P. U. Clark
(2008),
Distributed energy balance modeling of South Cascade Glacier, Washington and assessment of model uncertainty,
J. Geophys. Res.,
113,
F02019,
doi:10.1029/2007JF000850.
Copyright 2008 by the American Geophysical Union.
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