Near-margin ice thickness and subglacial water routing, Leverett Glacier, Greenland

Abstract

ABSTRACT Ice thickness measurements near the margin of the Greenland Ice Sheet (GrIS) are relatively sparse, presenting issues for modeling ice-flow dynamics, ice-sheet change, and subglacial hydrology. We acquired near-margin ice thickness data at Leverett Glacier, west Greenland, using a highly portable, low power, ground-penetrating radar operating at 10–80 MHz. Ice-thickness measurements, to a maximum of 270 m, were incorporated into the BedMachine model of ice thickness, created using mass conservation methods. The new data significantly modified the modeled ice thickness, and hence bed elevation and routing of subglacial water, in both the Leverett and adjacent Russell Glacier. Although the revised modeled basal topography and subglacial hydrology are consistent with observations, our new data unrealistically reduced the overall size of the Leverett Glacier hydrological catchment. Additional ice-thickness measurements are therefore required to realistically constrain subglacial topography and subglacial hydrological routing in this area. Our work improves understanding of the basal topography and the subglacial hydrology of Leverett Glacier, with implications for glacier dynamics and assessments of water piracy between catchments in the marginal zone of the GrIS, and for the interpolation of ice-thickness grids using mass conservation methods.