Published In

Journal of Glaciology

Document Type

Article

Publication Date

1-1-2002

Subjects

Ice streams -- Antarctica, Ice sheets -- Antarctica -- Dynamics, Glaciers -- Antarctica, Glacial landforms -- Antarctica

Abstract

The transition from inland- to streaming-style ice flow near to and upstream from the onset to Ice Stream D, West Antarctica, is investigated using the force- balance technique. Basal drag provides the majority of the flow resistance over the study area but is substantially modified by non-local stress gradients. Lateral drag increases with distance downstream, balancing ~50-100% of the driving stress at the onset. Longitudinal stress gradients (LSG) are also found to be significant, an observation that distinguishes ice flow in this region from the inland- and streaming-flow regimes that bound it, in which LSG are usually negligible. LSG decrease the spatial variability in basal drag and sliding speed and increase the area of the bed over which frictional melting occurs. Overall, LSG decrease the resistive influence of basal stress concentrations and increase the spatial uniformity of basal sliding. These observations suggest that streaming flow develops as an integrated response to the physical interaction between the ice and its bed over an extended region upstream from the onset, rather than being solely due to changes in basal characteristics at the onset. An implication is that non-steady-flow behavior upstream from the onset may ultimately propagate downstream and result in non-steady behavior at the onset.

Description

Originally appeared in the Journal of Glaciology, published by the International Glaciological Society. Article can be found at http://www.igsoc.org/journal/

DOI

10.3189/172756502781831539

Persistent Identifier

http://archives.pdx.edu/ds/psu/8437

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