TY - JOUR

T1 - Insights into ice stream dynamics through modelling their response to tidal forcing

AU - Rosier, S.H.

AU - Gudmundsson, G.H.

AU - Green, J.A.

N1 - UK Natural Environment Research Council through grant (NE/J/500203/1); Climate Change Consortium for Wales and from the NERC, grant NE/F014821/1 (Advanced Fellowship)

PY - 2014/9/25

Y1 - 2014/9/25

N2 - The tidal forcing of ice streams at their ocean boundary can serve as a natural experiment to gain an insight into their dynamics and constrain the basal sliding law. A nonlinear 3-D viscoelastic full Stokes model of coupled ice stream ice shelf flow is used to investigate the response of ice streams to ocean tides. In agreement with previous results based on flow-line modelling and with a fixed grounding line position, we find that a nonlinear basal sliding law can qualitatively reproduce long-period modulation of tidal forcing found in field observations. In addition, we show that the inclusion of lateral drag, or allowing the grounding line to migrate over the tidal cycle, does not affect these conclusions. Further analysis of modelled ice stream flow shows a varying stress-coupling length scale of boundary effects upstream of the grounding line. We derive a viscoelastic stress-coupling length scale from ice stream equations that depends on the forcing period and closely agrees with model output

AB - The tidal forcing of ice streams at their ocean boundary can serve as a natural experiment to gain an insight into their dynamics and constrain the basal sliding law. A nonlinear 3-D viscoelastic full Stokes model of coupled ice stream ice shelf flow is used to investigate the response of ice streams to ocean tides. In agreement with previous results based on flow-line modelling and with a fixed grounding line position, we find that a nonlinear basal sliding law can qualitatively reproduce long-period modulation of tidal forcing found in field observations. In addition, we show that the inclusion of lateral drag, or allowing the grounding line to migrate over the tidal cycle, does not affect these conclusions. Further analysis of modelled ice stream flow shows a varying stress-coupling length scale of boundary effects upstream of the grounding line. We derive a viscoelastic stress-coupling length scale from ice stream equations that depends on the forcing period and closely agrees with model output

U2 - 10.5194/tc-8-1763-2014

DO - 10.5194/tc-8-1763-2014

M3 - Article

VL - 8

SP - 1763

EP - 1775

JO - Cryosphere

JF - Cryosphere

SN - 1994-0416

ER -