Experimental determination of a double-valued drag relationship for glacier sliding
The contribution of glaciers to sea-level rise and their effects on landscape evolution depend on the poorly known relationship between sliding speed and drag at the ice/bed interface. Results from experiments with a new rotary laboratory device demonstrate empirically for the first time a double-va...
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ftiowastateuniv:oai:lib.dr.iastate.edu:ge_at_pubs-1135 2023-05-15T16:41:02+02:00 Experimental determination of a double-valued drag relationship for glacier sliding Zoet, Lucas K. Iverson, Neal R. 2015-02-01T08:00:00Z application/pdf https://lib.dr.iastate.edu/ge_at_pubs/152 https://lib.dr.iastate.edu/cgi/viewcontent.cgi?article=1135&context=ge_at_pubs en eng Iowa State University Digital Repository https://lib.dr.iastate.edu/ge_at_pubs/152 https://lib.dr.iastate.edu/cgi/viewcontent.cgi?article=1135&context=ge_at_pubs Creative Commons Attribution license. CC-BY Geological and Atmospheric Sciences Publications basal ice glacier flow glacier mechanics glacier modelling subglacial processes Geomorphology Glaciology text 2015 ftiowastateuniv 2021-08-28T22:47:00Z The contribution of glaciers to sea-level rise and their effects on landscape evolution depend on the poorly known relationship between sliding speed and drag at the ice/bed interface. Results from experiments with a new rotary laboratory device demonstrate empirically for the first time a double-valued drag relationship like that suggested by some sliding theories: steady drag on a rigid, sinusoidal bed increases, peaks and declines at progressively higher sliding speeds due to growth of cavities in the lee sides of bed undulations. Drag decreases with increased sliding speed if cavities extend beyond the inflection points of up-glacier facing surfaces, so that adverse bed slopes in contact with ice diminish with further cavity growth. These results indicate that shear tractions on glacier beds can potentially decrease due to increases in sliding speed driven by weather or climate variability, promoting even more rapid glacier motion by requiring greater strain rates to produce resistive stresses. Although a double-valued drag relationship has not yet been demonstrated for the complicated geometries of real glacier beds, both its potential major implications and the characteristically convex stoss surfaces of bumps on real glacier beds provide stimulus for exploring the effects of this relationship in ice-sheet models. Text Ice Sheet Digital Repository @ Iowa State University |
institution |
Open Polar |
collection |
Digital Repository @ Iowa State University |
op_collection_id |
ftiowastateuniv |
language |
English |
topic |
basal ice glacier flow glacier mechanics glacier modelling subglacial processes Geomorphology Glaciology |
spellingShingle |
basal ice glacier flow glacier mechanics glacier modelling subglacial processes Geomorphology Glaciology Zoet, Lucas K. Iverson, Neal R. Experimental determination of a double-valued drag relationship for glacier sliding |
topic_facet |
basal ice glacier flow glacier mechanics glacier modelling subglacial processes Geomorphology Glaciology |
description |
The contribution of glaciers to sea-level rise and their effects on landscape evolution depend on the poorly known relationship between sliding speed and drag at the ice/bed interface. Results from experiments with a new rotary laboratory device demonstrate empirically for the first time a double-valued drag relationship like that suggested by some sliding theories: steady drag on a rigid, sinusoidal bed increases, peaks and declines at progressively higher sliding speeds due to growth of cavities in the lee sides of bed undulations. Drag decreases with increased sliding speed if cavities extend beyond the inflection points of up-glacier facing surfaces, so that adverse bed slopes in contact with ice diminish with further cavity growth. These results indicate that shear tractions on glacier beds can potentially decrease due to increases in sliding speed driven by weather or climate variability, promoting even more rapid glacier motion by requiring greater strain rates to produce resistive stresses. Although a double-valued drag relationship has not yet been demonstrated for the complicated geometries of real glacier beds, both its potential major implications and the characteristically convex stoss surfaces of bumps on real glacier beds provide stimulus for exploring the effects of this relationship in ice-sheet models. |
format |
Text |
author |
Zoet, Lucas K. Iverson, Neal R. |
author_facet |
Zoet, Lucas K. Iverson, Neal R. |
author_sort |
Zoet, Lucas K. |
title |
Experimental determination of a double-valued drag relationship for glacier sliding |
title_short |
Experimental determination of a double-valued drag relationship for glacier sliding |
title_full |
Experimental determination of a double-valued drag relationship for glacier sliding |
title_fullStr |
Experimental determination of a double-valued drag relationship for glacier sliding |
title_full_unstemmed |
Experimental determination of a double-valued drag relationship for glacier sliding |
title_sort |
experimental determination of a double-valued drag relationship for glacier sliding |
publisher |
Iowa State University Digital Repository |
publishDate |
2015 |
url |
https://lib.dr.iastate.edu/ge_at_pubs/152 https://lib.dr.iastate.edu/cgi/viewcontent.cgi?article=1135&context=ge_at_pubs |
genre |
Ice Sheet |
genre_facet |
Ice Sheet |
op_source |
Geological and Atmospheric Sciences Publications |
op_relation |
https://lib.dr.iastate.edu/ge_at_pubs/152 https://lib.dr.iastate.edu/cgi/viewcontent.cgi?article=1135&context=ge_at_pubs |
op_rights |
Creative Commons Attribution license. |
op_rightsnorm |
CC-BY |
_version_ |
1766031479451680768 |