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Bed topography and surges in ice streams
Author(s) -
Schoof Christian
Publication year - 2004
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2003gl018807
Subject(s) - geology , drag , ice stream , surge , pressure ridge , ice sheet , mechanics , flow (mathematics) , pancake ice , streams , drumlin , geomorphology , sea ice , climatology , physics , cryosphere , computer network , computer science
Extensive bed topography at the scale of the ice thickness occurs frequently in the form of drumlins. By analogy with hard‐bed sliding, ice flow over this type of topography leads to the generation of drag on the ice, particularly when ice flow is rapid. A crucial difference with classical Nye‐Kamb sliding is that the upper, free surface of the ice has a significant effect on the sliding process through the formation of a standing wave. Using a theoretical model, we demonstrate that the presence of this wave introduces a non‐linearity into the sliding motion which can lead to multiple sliding velocities for the same large‐scale ice stream geometry, and that switches between these velocities can cause surging behavior.