Englacial latent-heat transfer has limited influence on seaward ice flux in western Greenland

• Published in: Journal of Glaciology
• Main Authors: POINAR, KRISTIN, JOUGHIN, IAN, LENAERTS, JAN T. M., VAN DEN BROEKE, MICHIEL R.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Cambridge University Press (CUP) 2016
• Subjects: Earth-Surface Processes; Greenland; Jakobshavn Isbræ; Ice Sheet; Jakobshavn; Jakobshavn isbræ; Journal of Glaciology
• Online Access: http://dx.doi.org/10.1017/jog.2016.103; https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0022143016001039

ABSTRACT Surface meltwater can refreeze within firn layers and crevasses to warm ice through latent-heat 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 Jakobshavn Isbræ regions of western Greenland using a numeric model and existing borehole measurements. We show that in the Jakobshavn catchment, meltwater percolation within the firn warms the ice at depth by 3–5°C. By contrast, meltwater refreezing in crevasses (cryo-hydrologic warming) at depths of ~300 m warms the ice in Pâkitsoq by up to 10°C, but this causes minimal increase in ice motion (<10 m a −1 ). Pâkitsoq is representative of western Greenland's land-terminating ice, where the slow movement of ice through a wide ablation zone provides ideal conditions for cryo-hydrologic warming to occur. We find that only ~37% of the western Greenland ice flux, however, travels through such areas. Overall, our findings suggest that cryo-hydrologic warming will likely have only a limited effect on the dynamic evolution of the Greenland ice sheet.