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Glaciological characteristics of Institute Ice Stream using remote sensing

Published online by Cambridge University Press:  03 June 2004

TED SCAMBOS
Affiliation:
National Snow and Ice Data Center, CIRES, UCB Box 449, 1540 30th Street, University of Colorado, Boulder, CO 80309, USA
JENNIFER BOHLANDER
Affiliation:
National Snow and Ice Data Center, CIRES, UCB Box 449, 1540 30th Street, University of Colorado, Boulder, CO 80309, USA
BRUCE RAUP
Affiliation:
National Snow and Ice Data Center, CIRES, UCB Box 449, 1540 30th Street, University of Colorado, Boulder, CO 80309, USA
TERRY HARAN
Affiliation:
National Snow and Ice Data Center, CIRES, UCB Box 449, 1540 30th Street, University of Colorado, Boulder, CO 80309, USA

Abstract

We assess the ice flow of Institute Ice Stream (IIS; 81.5°S, 75°W) and the adjacent Ronne Ice Shelf using satellite images and geophysical parameters from recent continent-wide compilations. Landsat image pairs from the 1980s and 1990s are used to determine ice velocity. Peak speed is 398 ± 10 m a−1. Several mappings using images spanning an eleven-year period indicate this speed and the pattern of ice flow throughout the mapped portion of the stream is constant to within ± 20 m a−1. Combining catchment extent (141 700 km2) with surface accumulation, mass input to IIS is 25.1 ± 2 Gt a−1. Mean ice thickness across the grounding line is 1177 m. Mass flux to the Ronne Ice Shelf, determined from these values and our velocity profile, is 22.7 ± 2 Gt a−1. Topographic mapping using photoclinometry, coupled with ice thickness and ice velocity, permits an assessment of driving force versus flow speed. This indicates wide variations in basal resistance. Despite evidence of present-day near-balance and constant speed in the ice stream trunk, a recent change in outflow is implied by folding of shelf streaklines near Korff Ice Rise. This may be a result of changing shelf thickness or erosion of Doake Ice Rumples.

Type
Research Article
Copyright
© Antarctic Science Ltd 2004

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