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Evaluation of remote-sensing techniques to measure decadal-scale changes of Hofsjokull ice cap, Iceland

September 16, 2000

Dynamic surficial changes and changes in the position of the firn line and the areal extent of Hofsjökull ice cap, Iceland, were studied through analysis of a time series (1973–98) of synthetic-aperture radar (SAR) and Landsat data. A digital elevation model of Hofsjökull, which was constructed using SAR interferometry, was used to plot the SAR backscatter coefficient (σ°) vs elevation and air temperature along transects across the ice cap. Seasonal and daily σ° patterns are caused by freezing or thawing of the ice-cap surface, and abrupt changes in σ° are noted when the air temperature ranges from ∼−5° to 0°C. Late-summer 1997 σ° (SAR) and reflectance (Landsat) boundaries agree and appear to be coincident with the firn line and a SAR σ° boundary that can be seen in the January 1998 SAR image. In January 1994 through 1998, the elevation of this σ° boundary on the ice capwas quite stable, ranging from 1000 to 1300 m, while the equilibrium-line altitude, as measured on the ground, varied considerably. Thus the equilibrium line may be obscured by firn from previous years. Techniques are established to measure long-term changes in the elevation of the firn line and changes in the position of the ice margin.

Publication Year 2000
Title Evaluation of remote-sensing techniques to measure decadal-scale changes of Hofsjokull ice cap, Iceland
DOI 10.3189/172756500781833061
Authors D.K. Hall, R.S. Williams, J.S. Barton, O. Sigurdsson, L.C. Smith, J.B. Garvin
Publication Type Article
Publication Subtype Journal Article
Series Title Journal of Glaciology
Index ID 70125319
Record Source USGS Publications Warehouse
USGS Organization Coastal and Marine Geology Program; Woods Hole Coastal and Marine Science Center
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