Structure and dynamics of a subglacial discharge plume in a Greenlandic fjord

• Published in: Journal of Geophysical Research: Oceans
• Main Authors: Mankoff, Kenneth D., Straneo, Fiamma, Cenedese, Claudia, Das, Sarah B., Richards, Clark G., Singh, Hanumant
• Format: Article in Journal/Newspaper
• Language: English
• Published: John Wiley & Sons 2016
• Subjects: Greenland; Glacier; Fjord; Ice; Ocean; Plume; Arctic; Climate change; glacier; greenlandic
• Online Access: https://hdl.handle.net/1912/8810

Author Posting. © American Geophysical Union, 2016. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Journal of Geophysical Research: Oceans 121 (2016): 8670–8688, doi:10.1002/2016JC011764. Discharge of surface-derived meltwater at the submerged base of Greenland's marine-terminating glaciers creates subglacial discharge plumes that rise along the glacier/ocean interface. These plumes impact submarine melting, calving, and fjord circulation. Observations of plume properties and dynamics are challenging due to their proximity to the calving edge of glaciers. Therefore, to date information on these plumes has been largely derived from models. Here we present temperature, salinity, and velocity data collected in a plume that surfaced at the edge of Saqqarliup Sermia, a midsized Greenlandic glacier. The plume is associated with a narrow core of rising waters approximately 20 m in diameter at the ice edge that spreads to a 200 m by 300 m plume pool as it reaches the surface, before descending to its equilibrium depth. Volume flux estimates indicate that the plume is primarily driven by subglacial discharge and that this has been diluted in a ratio of 1:10 by the time the plume reaches the surface. While highly uncertain, meltwater fluxes are likely 2 orders of magnitude smaller than the subglacial discharge flux. The overall plume characteristics agree with those predicted by theoretical plume models for a convection-driven plume with limited influence from submarine melting. National Science Foundation (NSF) Grant Numbers: PLR-1418256 , OCE-1434041; Woods Hole Oceanographic Institution (WHOI) Ocean and Climate Change Institute (OCCI) Arctic Research Initiative OCCI; National Aeronautics and Space Administration Grant Number: NNX10AN83H 2017-06-15