Derived Bedrock Elevations, Strain Rates, and Stresses from Measured Surface Elevations and Velocities: Jakobshavns Isbrae, Greenland
. Jakobshavns Isbrae (69 o 10'N, 49 o 59'W) drains about 6.5 percent of the Greenland Ice Sheet and is the fastest ice stream known. The Jakobshavns Isbrae basin of about 10,000 km 2 was mapped photogrammetrically from four sets of aerial photography, two taken in July 1985 and two in July...
| Main Authors: | , , , , , |
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| Other Authors: | |
| Format: | Text |
| Language: | English |
| Published: |
1992
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| Subjects: | |
| Online Access: | http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.55.9011 http://www.umcs.maine.edu/~shamis/papers/jacob/jacob4.ps |
| Summary: | . Jakobshavns Isbrae (69 o 10'N, 49 o 59'W) drains about 6.5 percent of the Greenland Ice Sheet and is the fastest ice stream known. The Jakobshavns Isbrae basin of about 10,000 km 2 was mapped photogrammetrically from four sets of aerial photography, two taken in July 1985 and two in July 1986. Positions and elevations of several hundred natural features on the ice surface were determined for each epoch by photogrammetric block aerial triangulation, and surface velocity vectors were computed from the positions. The two flights in 1985 yielded the best results and provided the most common points (716) for velocity determinations and are therefore used in the modeling studies. The data at these irregularly spaced points were used to calculate ice elevations and velocity vectors at uniformly spaced gridpoints 3 km apart by interpolation. The field of surface strain rates was then calculated from this gridded data and used to compute the field of surface deviatoric stresses, using t. |
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