Meltwater delivered to the bed of the Greenland Ice Sheet is a driver of variable ice-motion through changes in effective pressure and enhanced basal lubrication. Ice surface velocities have been shown to respond rapidly both to meltwater production at the surface and to drainage of supraglacial lakes, suggesting efficient transfer of meltwater from the supraglacial to subglacial hydrological s...

Meltwater discharge and electrical conductivity were measured in eight 1 3 1 m lysimeters, and snow accumulation and electrical conductivity of melted samples were measured in snow pits during four snowmelt seasons at Mammoth Mountain, California. The peak snow-water equivalent ranged from 0.57 to 2.92 m over the four melt seasons. Lysimeter discharges ranged from 20% to 205% of the mean flow; ...

Meltwater is produced on the surface of glaciers and ice sheets when the seasonal surface energy forcing warms the snow to its melting temperature. This meltwater can run off the surface in streams or percolate through the porous snow and refreeze, which warms the subsurface through the release of latent heat. We model the percolation process from first principles using a continuum model that i...

Rising sea levels and increased surface melting of the Greenland ice sheet have heightened the need for direct observations of meltwater release from the ice edge to ocean. Buoyant sediment plumes that develop in fjords downstream of outlet glaciers are controlled by numerous factors, including meltwater runoff. Here, Moderate Resolution Imaging Spectroradiometer (MODIS) satellite imagery is us...

Predicting Greenland Ice Sheet mass loss due to ice dynamics requires a complete understanding of spatiotemporal velocity fluctuations and related control mechanisms. We present a 5 year record of seasonal velocity measurements for 55 marine-terminating glaciers distributed around the ice sheet margin, along with ice-front position and runoff data sets for each glacier. Among glaciers with subs...

Surface meltwater can refreeze within firn layers and crevasses to warm ice through latentheat transfer on decadal to millennial timescales. Earlier work posited that the consequent softening of the ice might accelerate ice flow, potentially increasing ice-sheet mass loss. Here, we calculate the effect of meltwater refreezing on ice temperature and softness in the Pâkitsoq (near Swiss Camp) and...

Evidence from the Irish Sea basin supports the existence of an abrupt rise in sea level (meltwater pulse) at 19,000 years before the present (B.P.). Climate records indicate a large reduction in the strength of North Atlantic Deep Water formation and attendant cooling of the North Atlantic at this time, indicating a source of the meltwater pulse from one or more Northern Hemisphere ice sheets. ...