Sustained high basal motion of the Greenland ice sheet revealed by borehole deformation

Claudia Ryser; Martin P. Luethi; Lauren C. Andrews; Matthew J. Hoffman; Ginny A. Catania; Robert L. Hawley; Thomas A. Neumann; Steen Savstrup Kristensen

doi:10.3189/2014JoG13J196

Sustained high basal motion of the Greenland ice sheet revealed by borehole deformation

Claudia Ryser, Martin P. Luethi, Lauren C. Andrews, Matthew J. Hoffman, Ginny A. Catania, Robert L. Hawley, Thomas A. Neumann, Steen Savstrup Kristensen

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Abstract

Ice deformation and basal motion characterize the dynamical behavior of the Greenland ice sheet (GrIS). We evaluate the contribution of basal motion from ice deformation measurements in boreholes drilled to the bed at two sites in the western marginal zone of the GrIS. We find a sustained high amount of basal motion contribution to surface velocity of 44-73% in winter, and up to 90% in summer. Measured ice deformation rates show an unexpected variation with depth that can be explained with the help of an ice-flow model as a consequence of stress transfer from slippery to sticky areas. This effect necessitates the use of high-order ice-flow models, not only in regions of fast-flowing ice streams but in all temperate-based areas of the GrIS. The agreement between modeled and measured deformation rates confirms that the recommended values of the temperature-dependent flow rate factor A are a good choice for ice-sheet models.

Original language	English
Journal	Journal of Glaciology
Volume	60
Issue number	222
Pages (from-to)	647-660
Number of pages	14
ISSN	0022-1430
DOIs	https://doi.org/10.3189/2014JoG13J196
Publication status	Published - 2014

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title = "Sustained high basal motion of the Greenland ice sheet revealed by borehole deformation",

abstract = "Ice deformation and basal motion characterize the dynamical behavior of the Greenland ice sheet (GrIS). We evaluate the contribution of basal motion from ice deformation measurements in boreholes drilled to the bed at two sites in the western marginal zone of the GrIS. We find a sustained high amount of basal motion contribution to surface velocity of 44-73% in winter, and up to 90% in summer. Measured ice deformation rates show an unexpected variation with depth that can be explained with the help of an ice-flow model as a consequence of stress transfer from slippery to sticky areas. This effect necessitates the use of high-order ice-flow models, not only in regions of fast-flowing ice streams but in all temperate-based areas of the GrIS. The agreement between modeled and measured deformation rates confirms that the recommended values of the temperature-dependent flow rate factor A are a good choice for ice-sheet models.",

author = "Claudia Ryser and Luethi, {Martin P.} and Andrews, {Lauren C.} and Hoffman, {Matthew J.} and Catania, {Ginny A.} and Hawley, {Robert L.} and Neumann, {Thomas A.} and Kristensen, {Steen Savstrup}",

year = "2014",

doi = "10.3189/2014JoG13J196",

language = "English",

volume = "60",

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TY - JOUR

T1 - Sustained high basal motion of the Greenland ice sheet revealed by borehole deformation

AU - Ryser, Claudia

AU - Luethi, Martin P.

AU - Andrews, Lauren C.

AU - Hoffman, Matthew J.

AU - Catania, Ginny A.

AU - Hawley, Robert L.

AU - Neumann, Thomas A.

AU - Kristensen, Steen Savstrup

PY - 2014

Y1 - 2014

N2 - Ice deformation and basal motion characterize the dynamical behavior of the Greenland ice sheet (GrIS). We evaluate the contribution of basal motion from ice deformation measurements in boreholes drilled to the bed at two sites in the western marginal zone of the GrIS. We find a sustained high amount of basal motion contribution to surface velocity of 44-73% in winter, and up to 90% in summer. Measured ice deformation rates show an unexpected variation with depth that can be explained with the help of an ice-flow model as a consequence of stress transfer from slippery to sticky areas. This effect necessitates the use of high-order ice-flow models, not only in regions of fast-flowing ice streams but in all temperate-based areas of the GrIS. The agreement between modeled and measured deformation rates confirms that the recommended values of the temperature-dependent flow rate factor A are a good choice for ice-sheet models.

AB - Ice deformation and basal motion characterize the dynamical behavior of the Greenland ice sheet (GrIS). We evaluate the contribution of basal motion from ice deformation measurements in boreholes drilled to the bed at two sites in the western marginal zone of the GrIS. We find a sustained high amount of basal motion contribution to surface velocity of 44-73% in winter, and up to 90% in summer. Measured ice deformation rates show an unexpected variation with depth that can be explained with the help of an ice-flow model as a consequence of stress transfer from slippery to sticky areas. This effect necessitates the use of high-order ice-flow models, not only in regions of fast-flowing ice streams but in all temperate-based areas of the GrIS. The agreement between modeled and measured deformation rates confirms that the recommended values of the temperature-dependent flow rate factor A are a good choice for ice-sheet models.

U2 - 10.3189/2014JoG13J196

DO - 10.3189/2014JoG13J196

M3 - Journal article

SN - 0022-1430

VL - 60

SP - 647

EP - 660

JO - Journal of Glaciology

JF - Journal of Glaciology

IS - 222

ER -

Sustained high basal motion of the Greenland ice sheet revealed by borehole deformation

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