Using GPS to Determine Local Surface Mass Balance

des Instituts für Geodäsie

Heft 50/1997

Using GPS
to Determine Local Surface Mass Balance:

A Case Study on the Taku Glacier, Alaska, 1993-1995

Scott R. McGEE

In: WELSCH, Walter M. / LANG, Martin / MILLER, Maynard M. (Hrsg.) [1997]:
Geodetic Activities Juneau Icefield, Alaska, 1981-1996.
Schriftenreihe des Studiengangs Vermessungswesen der Universität der Bundeswehr München, Heft 50, Neubiberg, S. 127-135.


This study has confirmed the utility and validity of a GPS-based approach to local surface mass balance determination. Used in conjunction with three-dimensinal surface modeling, GPS-derived data allow a very detailed analysis and quantification of the spatial and temporal mass balance changes to be made. The local surface mass changes observed at Profile IV on the Takun Glacier since 1993 appear to indicate an overall loss of mass. It must be cautioned however, that this apparent loss of mass may be due to factors other than actual mass loss; for example, the movement of a kinematic wave through the profile could produce data with the observed characteristics. The current study of Profile IV is too limited to be able to determine the exact cause of surface elevation changes and mass loss or accumulation. For this kind of determination to be reliably made, a greater number of profiles in the vicinity of Profile IV, both up-glacier and down-glacier, would have to be established and monitored.

The current two year study reported here cannot yet reveal long-term mass balance trends at this profile. Continued annual monitoring of the profile utilizing GPS and surface modeling will prove invaluable in documenting the ever-changing annual mass balance and will eventually provide a long-term examination of the surface mass balance regime of Profile IV.

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