Meltwater generation in ice stream shear margins: case study in Antarctic ice streams

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Authors

Meghana Ranganathan , Jack-William Barotta, Colin R. Meyer, Brent Minchew

Abstract

Liquid water within glacier ice and at the glacier beds exerts a significant control on ice flow and glacier stability through a number of processes, including altering the rheology of the ice and lubricating the bed. Some of this water is generated as melt in regions of rapid deformation, including shear margins, due to heating by viscous dissipation. However, how much meltwater is generated and drained from shear margins remains unclear. Here, we apply a model that describes the evolution of ice temperature, melting, and water transport within deforming ice to estimate the flux of meltwater from shear margins in glaciers. We derive analytical expressions for ice temperature, effective pressure, and porosity in zones of temperate ice, and we apply this model to estimate the flux from three Antarctic glaciers: Bindschadler and MacAyeal Ice Streams, Pine Island Glacier, and Byrd Glacier. We show that the flux of meltwater from shear margins in these regions may be as significant as the meltwater produced by frictional heating at the bed, with average fluxes of ~1000-2000 m^3 yr^ -1. This contribution of shear heating to meltwater flux at the bed may thus affect both the rheology of the ice as well as sliding at the bed, both key controls on fast ice flow.

DOI

https://doi.org/10.31223/X5BK8D

Subjects

Earth Sciences, Glaciology, Physical Sciences and Mathematics

Keywords

Antarctica, ice sheets, glacier hydrology, meltwater, temperate ice

Dates

Published: 2022-01-05 11:12

Last Updated: 2022-01-06 05:13

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License

CC BY Attribution 4.0 International

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Data Availability (Reason not available):
The source code for the model presented in this study, along with the data needed to generate Figure 4, are openly available at https://github.com/megr090/MeltwaterFlux. No new data were produced for this study, and data used in this study are publicly available through their respective publications.

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