Heat sources for glacial ice melt in a West Greenland tidewater outlet glacier fjord: The role of subglacial freshwater discharge

• Published in: Geophysical Research Letters
• Main Authors: Bendtsen, Jørgen, Mortensen, John, Lennert, Kunuk, Rysgaard, Søren
• Format: Article in Journal/Newspaper
• Language: English
• Published: 2015
• Subjects: Greenland; glacier; Ice Sheet; Tidewater
• Online Access: https://pure.au.dk/portal/en/publications/a7242a5e-04e3-453a-99e9-7d9b5338302a; https://doi.org/10.1002/2015GL063846; http://onlinelibrary.wiley.com/doi/10.1002/2015GL063846/full

The melting of tidewater outlet glaciers from the Greenland Ice Sheet contributes significantly to global sea level rise. Accelerated mass loss is related to melt-processes in front of calving glaciers, yet the role of ocean heat transports is poorly understood. Here we present the first direct measurements from a subglacial plume in front of a calving tidewater outlet glacier. Surface salinity in the plume corresponded to a meltwater content of 7 %, which is indicative of significant entrainment of warm bottom water and, according to plume model calculations, significant ice melt. Energy balance of the area near the glacier showed that ice melt was mainly due to ocean heat transport and that direct plume-associated melt was only important in periods with high meltwater discharge rates of ~100 m3 s−1. Ocean mixing outside of the plume area was thus the primary heat source for melting glacier ice.