Insights on the formation of longitudinal surface structures on ice sheets from analysis of their spacing, spatial distribution and relationship to ice thickness and flow

J. C. Ely (Corresponding Author), C.D. Clark, F. S. L. Ng, M. Spagnolo

Research output: Contribution to journalArticle

4 Citations (Scopus)
4 Downloads (Pure)

Abstract

Longitudinal surface structures (LSSs) are prevalent upon the ice streams, ice shelves and outlet glaciers of ice sheets. These features inform our understanding of past and present ice sheet behavior. However, consensus regarding their genesis has not been reached. Here we analyze 42,311 LSS segments mapped across Antarctica together with geophysical data to determine their morphological and glaciological properties. Most LSSs are spaced 450 to 1500 m apart, a distance positively correlated with the width of the ice flow unit on which they occur. The start points (upstream end locations) of LSSs have diverse ice thicknesses and velocities. The majority of LSSs occur where ice flow is converging or broadly parallel, and they are prominent at ice confluences. Some occur at slow-flowing ice stream onsets. Occasionally, LSSs relate to sudden variations in basal shear stress due to basal perturbations. From these observations, we argue that LSSs are the consequence of increased strain which occurs during the lateral compression and longitudinal extension of ice: (i) converging/flowing into a channel (this scenario characterizes most LSSs), (ii) at the onset of ice streaming, (iii) at flow unit confluence, and (iv) as ice flows over and around a basal perturbation.
Original languageEnglish
Pages (from-to)961–972
Number of pages12
JournalJournal of Geophysical Research: Earth Surface
Volume122
Issue number4
Early online date20 Apr 2017
DOIs
Publication statusPublished - Apr 2017

Fingerprint

Ice Cover
ice flow
ice thickness
Ice
Surface structure
Spatial distribution
ice sheet
spatial distribution
ice
spacing
ice stream
confluence
perturbation
analysis
ice shelf
land ice
shear stress
glaciers
Glaciers
glacier

Keywords

  • Ice Sheet
  • Flow Stripe
  • Longitudinal Surface Structures
  • Outlet Glaciers
  • Structural Glaciology

ASJC Scopus subject areas

  • Agricultural and Biological Sciences(all)
  • Earth and Planetary Sciences(all)
  • Environmental Science(all)

Cite this

Insights on the formation of longitudinal surface structures on ice sheets from analysis of their spacing, spatial distribution and relationship to ice thickness and flow. / Ely, J. C. (Corresponding Author); Clark, C.D.; Ng, F. S. L.; Spagnolo, M.

In: Journal of Geophysical Research: Earth Surface, Vol. 122, No. 4, 04.2017, p. 961–972.

Research output: Contribution to journalArticle

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abstract = "Longitudinal surface structures (LSSs) are prevalent upon the ice streams, ice shelves and outlet glaciers of ice sheets. These features inform our understanding of past and present ice sheet behavior. However, consensus regarding their genesis has not been reached. Here we analyze 42,311 LSS segments mapped across Antarctica together with geophysical data to determine their morphological and glaciological properties. Most LSSs are spaced 450 to 1500 m apart, a distance positively correlated with the width of the ice flow unit on which they occur. The start points (upstream end locations) of LSSs have diverse ice thicknesses and velocities. The majority of LSSs occur where ice flow is converging or broadly parallel, and they are prominent at ice confluences. Some occur at slow-flowing ice stream onsets. Occasionally, LSSs relate to sudden variations in basal shear stress due to basal perturbations. From these observations, we argue that LSSs are the consequence of increased strain which occurs during the lateral compression and longitudinal extension of ice: (i) converging/flowing into a channel (this scenario characterizes most LSSs), (ii) at the onset of ice streaming, (iii) at flow unit confluence, and (iv) as ice flows over and around a basal perturbation.",
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