Geodetic massbalance of Svartisen ice cap
Cecilie, Rolstad DenbyProject period: 2007-2009.
Staff: C. Rolstad, Master student T. Haug
Geodetic mass balance
The geodetic mass balance of the western Svartisen ice cap in northern Norway is determined,in from photogrammetry on vertical aerial photographs taken in 1968, 1985 and 2002.The existing 1968 digital terrain model (DTM) was generated using analogue photogrammetry, and the 1985 and 2002 DTMs are newly generated using digital photogrammetry. The geodetic mass balance for 1968–85 is –2.6±0.8mw.e., and for 1985–2002 it is –2.0±1.6mw.e. The area of western Svartisen decreased from 190 km2 in 1968, to 187 km2 in 1985 and to 184 km2 in 2002.
Surveying, Engabreen, Svartisen
Photo:
Uncertainty estimate – spatial statistics
Traditional mass balance estimates and geodetic mass balance estimates can differ significantly. It is therefore a need to improve uncertainty estimates in both methods. This study focuses on the uncertainties in the geodetic mass balance. A geostatistical assessment of the elevations derived from stereo photogrammetry surrounding the glacier is done, and these are applied to indicate the uncertainties in the elevation changes of the glacier surface. Spatially averaged uncertainty is dependent not only on the standard error of individual elevation changes, but also on the size of the averaging area and the scale of spatial autocorrelation. Concurrent photogrammetrical and laser scanning data are also used to evaluate the dependency of the geostatistics on the surface type.
This work is conducted in cooperation with the Norwegian Water Resources and Energy Directorate (NVE), and the B. Denby, the Norwegian Institute for Air Research (NILU).
From Mass balance workshop at Skeikampen, 2008.
Publications
Haug, T, Rolstad, C., H. Elvehøy, M. Jackson and I. M-Johansen, 2009. Geodetic mass balance of the western Svartisen ice cap, Norway, in the periods 1968 - 1985 and 1985 - 2002. Annals of Glaciology 50(50), 119-125.
Rolstad, C., T. Haug and B. Denby, 2009. Geodetic glacier mass balance uncertainty – assessment of photogrammetrical elevation errors using spatial statistics and laser scanning data. Journal of Glaciology, 55(192), 666-680.
Published: 16.04.00
Updated: 23.04.10
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Contact: Cecilie Rolstad (cecilie.rolstad@umb.no)