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Short-term variability in Greenland Ice Sheet motion forced by time-varying meltwater drainage: implications for the relationship between subglacial drainage system behavior and ice velocity

journal contribution
posted on 2023-05-17, 23:06 authored by Bartholomew, I, Nienow, P, Sole, A, Mair, D, Cowton, T, Matt KingMatt King
High resolution measurements of ice motion along a ~120 km transect in a land-terminating section of the GrIS reveal short-term velocity variations (<1 day), which are forced by rapid variations in meltwater input to the subglacial drainage system from the ice sheet surface. The seasonal changes in ice velocity at low elevations (<1000 m) are dominated by events lasting from 1 day to 1 week, although daily cycles are largely absent at higher elevations, reflecting different patterns of meltwater input. Using a simple model of subglacial conduit behavior we show that the seasonal record of ice velocity can be understood in terms of a time-varying water input to a channelized subglacial drainage system. Our investigation substantiates arguments that variability in the duration and rate, rather than absolute volume, of meltwater delivery to the subglacial drainage system are important controls on seasonal patterns of subglacial water pressure, and therefore ice velocity. We suggest that interpretations of hydro-dynamic behavior in land-terminating sections of the GrIS margin which rely on steady state drainage theories are unsuitable for making predictions about the effect of increased summer ablation on future rates of ice motion.

History

Publication title

Journal of Geophysical Research

Volume

117

Issue

F3

Article number

F03002

Number

F03002

Pagination

1-17

ISSN

0148-0227

Department/School

School of Geography, Planning and Spatial Sciences

Publisher

Amer Geophysical Union

Place of publication

2000 Florida Ave Nw, Washington, USA, Dc, 20009

Rights statement

Copyright 2012 American Geophysical Union

Repository Status

  • Restricted

Socio-economic Objectives

Understanding climate change not elsewhere classified

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