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Re-analysis of Alaskan benchmark glacier mass-balance data using the index method

Scientific Investigations Report 2010-5247

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Abstract

At Gulkana and Wolverine Glaciers, designated the Alaskan benchmark glaciers, we re-analyzed and re-computed the mass balance time series from 1966 to 2009 to accomplish our goal of making more robust time series. Each glacier's data record was analyzed with the same methods. For surface processes, we estimated missing information with an improved degree-day model. Degree-day models predict ablation from the sum of daily mean temperatures and an empirical degree-day factor. We modernized the traditional degree-day model and derived new degree-day factors in an effort to match the balance time series more closely. We estimated missing yearly-site data with a new balance gradient method. These efforts showed that an additional step needed to be taken at Wolverine Glacier to adjust for non-representative index sites. As with the previously calculated mass balances, the re-analyzed balances showed a continuing trend of mass loss. We noted that the time series, and thus our estimate of the cumulative mass loss over the period of record, was very sensitive to the data input, and suggest the need to add data-collection sites and modernize our weather stations.

Additional Publication Details

Publication type:
Report
Publication Subtype:
USGS Numbered Series
Title:
Re-analysis of Alaskan benchmark glacier mass-balance data using the index method
Series title:
Scientific Investigations Report
Series number:
2010-5247
Year Published:
2010
Language:
English
Publisher:
U.S. Geological Survey
Contributing office(s):
Alaska Science Center Water
Description:
vi, 14 p.; Appendix
Number of Pages:
16
Country:
United States
Online Only (Y/N):
N
Additional Online Files(Y/N):
N