Abstract
ABSTRACTOver recent decades, Greenland ice sheet surface melt has shown an increase both in intensity and spatial extent. Part of this water probably reaches the bed and can enhance glacier speed, advecting a larger volume of ice into the ablation area. In the context of a warming climate, this mechanism could contribute to the future rate of thinning and retreat of land-terminating glaciers of Greenland. These changes in ice flow conditions will in turn influence surface crevassing and thus the ability of water to reach the bed at higher elevations. Here, using a coupled basal hydrology and prognostic ice flow model, the evolution of a Greenland-type glacier subject to increasing surface melt is studied over a few decades. For different scenarios of surface melt increase over the next decades, the evolution of crevassed areas and the ability of water to reach the bed is inferred. Our results indicate that the currently observed crevasse distribution is likely to extend further upstream which will allow water to reach the bed at higher elevations. This will lead to an increase in ice flux into the ablation area which, in turn, accelerates the mass loss of land-terminating glaciers.
Highlights
The Greenland ice sheet is losing mass at an increasing rate (Kjeldsen and others, 2015), almost distributed between an increase in the surface melt during summer and an acceleration of flux to the ocean through marine-terminating outlets (Van den Broeke and others, 2016; van den Broeke and others, 2017)
Even though the ability of surface meltwater to modulate the flow of alpine glaciers at diurnal and seasonal timescale has been known for a long time (e.g. Lliboutry, 1958; Iken and Bindschadler, 1987; Mair and others, 2003), it is only relatively recently that this process was shown to operate for larger ice masses such as Greenland outlet glaciers (Zwally and others, 2002)
Our model results suggest that the crevassed areas of the land-terminating outlet glaciers of Greenland will move further inland as climate change increases the area affected by surface melt, with the consequence that surface meltwater can access the bed further inland
Summary
The Greenland ice sheet is losing mass at an increasing rate (Kjeldsen and others, 2015), almost distributed between an increase in the surface melt during summer and an acceleration of flux to the ocean through marine-terminating outlets (Van den Broeke and others, 2016; van den Broeke and others, 2017). This latter contribution has been shown to be mostly controlled by processes acting at the front of glaciers, where the ice meets the ocean (e.g. Rignot and others, 2010). This shows that the relation between the amount of run-off and ice flow speed is complex and variable in time and space, reflecting the evolution of the basal drainage system during the melt season (e.g. Bartholomew and others, 2010; Schoof, 2010)
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
