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Tidal Grounding‐Line Migration Modulated by Subglacial Hydrology
Author(s) -
Warburton K. L. P.,
Hewitt D. R.,
Neufeld J. A.
Publication year - 2020
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 - 10.1029/2020gl089088
Subject(s) - geology , context (archaeology) , geophysical fluid dynamics , geomorphology , geophysics , climatology , paleontology
We present a mathematical model of the hydrology of grounding‐line migration on tidal timescales, in which the ice acts elastically, overlying a connected hydrological network, with the ocean tides modeled by an oscillating far‐field fluid height. The upstream grounding‐line migration is driven by a fluid pressure gradient through the grounding zone, while the downstream migration is limited by fluid drainage through the till. The two processes are described using separate travelling‐wave solutions, based on a model of fluid flow under an elastic sheet. The asymmetry between the upstream and downstream motion allows the grounding line to act as a nonlinear filter on the tidal forcing as the pressure signal propagates upstream, and this frequency modulation is discussed in the context of velocity data from ice streams across Antarctica to provide a novel constraint on till permeability.