title: Sensitive response of the Greenland Ice Sheet to surface melt drainage over a soft bed.
abstract: The dynamic response of the Greenland Ice Sheet (GrIS) depends on feedbacks between surface meltwater delivery to the subglacial environment and ice flow. Recent work has highlighted an important role of hydrological processes in regulating the ice flow, but models have so far overlooked the mechanical effect of soft basal sediment. Here we use a three-dimensional model to investigate hydrological controls on a GrIS soft-bedded region. Our results demonstrate that weakening and strengthening of subglacial sediment, associated with the seasonal delivery of surface meltwater to the bed, modulates ice flow consistent with observations. We propose that sedimentary control on ice flow is a viable alternative to existing models of evolving hydrological systems, and find a strong link between the annual flow stability, and the frequency of high meltwater discharge events. Consequently, the observed GrIS resilience to enhanced melt could be compromised if runoff variability increases further with future climate warming.
authors.affiliation: Scott Polar Research Institute, Department of Geography, University of Cambridge, Cambridge CB2 1ER, UK.
authors.forename: M
authors.initials: M
authors.lastname: Bougamont
authors.affiliation: Scott Polar Research Institute, Department of Geography, University of Cambridge, Cambridge CB2 1ER, UK.
authors.forename: P
authors.initials: P
authors.lastname: Christoffersen
authors.affiliation: Centre for Glaciology, Department of Geography and Earth Sciences, University of Aberystwyth, Aberystwyth SY23 3DB, UK.
authors.forename: A L
authors.initials: AL
authors.lastname: Hubbard
authors.affiliation: Centre for Glaciology, Department of Geography and Earth Sciences, University of Aberystwyth, Aberystwyth SY23 3DB, UK.
authors.forename: A A
authors.initials: AA
authors.lastname: Fitzpatrick
authors.affiliation: Centre for Glaciology, Department of Geography and Earth Sciences, University of Aberystwyth, Aberystwyth SY23 3DB, UK.
authors.forename: S H
authors.initials: SH
authors.lastname: Doyle
authors.affiliation: Scripps Institution of Oceanography, Institute of Geophysics and Planetary Physics, University of California, San Diego, CA 92093, USA.
authors.forename: S P
authors.initials: SP
authors.lastname: Carter