Thermodynamics of a fast-moving Greenlandic outlet glacier revealed by fiber-optic distributed temperature sensing. ...

• Main Authors: Law, Robert, Christoffersen, Poul, Hubbard, Bryn, Doyle, Samuel H, Chudley, Thomas R, Schoonman, Charlotte M, Bougamont, Marion, Des Tombe, Bas, Schilperoort, Bart, Kechavarzi, Cedric, Booth, Adam, Young, Tun Jan
• Format: Article in Journal/Newspaper
• Language: English
• Published: American Association for the Advancement of Science (AAAS) 2021
• Subjects: 37 Earth Sciences; 3709 Physical Geography and Environmental Geoscience; 3705 Geology; Greenland; Kujalleq; glacier; greenlandic; Sermeq Kujalleq
• Online Access: https://dx.doi.org/10.17863/cam.70252; https://www.repository.cam.ac.uk/handle/1810/322796

Measurements of ice temperature provide crucial constraints on ice viscosity and the thermodynamic processes occurring within a glacier. However, such measurements are presently limited by a small number of relatively coarse-spatial-resolution borehole records, especially for ice sheets. Here, we advance our understanding of glacier thermodynamics with an exceptionally high-vertical-resolution (~0.65 m), distributed-fiber-optic temperature-sensing profile from a 1043-m borehole drilled to the base of Sermeq Kujalleq (Store Glacier), Greenland. We report substantial but isolated strain heating within interglacial-phase ice at 208 to 242 m depth together with strongly heterogeneous ice deformation in glacial-phase ice below 889 m. We also observe a high-strain interface between glacial- and interglacial-phase ice and a 73-m-thick temperate basal layer, interpreted as locally formed and important for the glacier's fast motion. These findings demonstrate notable spatial heterogeneity, both vertically and at the ...