[en] Meltwater from the Greenland Ice Sheet often drains subglacially into fjords, driving upwelling plumes at glacier termini. Ocean models and observations of submarine termini suggest that plumes enhance melt and undercutting, leading to calving and potential glacier destabilization. Here we systematically evaluate how simulated plume structure and submarine melt during summer months depends on realistic ranges of subglacial discharge, glacier depth, and ocean stratification from 12 Greenland fjords. Our results show that grounding line depth is a strong control on plume-induced submarine melt: deep glaciers produce warm, salty subsurface plumes that undercut termini, and shallow glaciers produce cold, fresh surface-trapped plumes that can overcut termini. Due to sustained upwelling velocities, plumes in cold, shallow fjords can induce equivalent depth-averaged melt rates compared to warm, deep fjords. These results detail a direct ocean-ice feedback that can affect the Greenland Ice Sheet.
Disciplines :
Earth sciences & physical geography
Author, co-author :
Carroll, D.; Department of Earth Sciences, University of Oregon, Eugene, United States
Sutherland, D.A.; Department of Earth Sciences, University of Oregon, Eugene, United States
Hudson, B.; Applied Physics Laboratory, University of Washington, Seattle, United States
Moon, T.; Department of Earth Sciences, University of Oregon, Eugene, United States ; Bristol Glaciology Centre, School of Geographical Sciences, University of Bristol, Bristol, United Kingdom
Catania, G.A.; Institute for Geophysics, University of Texas, Austin, United States ; Department of Geology, University of Texas, Austin, United States
Shroyer, E.L.; College of Earth, Ocean, and Atmospheric Sciences, Oregon State University, Corvallis, United States
Nash, J.D.; College of Earth, Ocean, and Atmospheric Sciences, Oregon State University, Corvallis, United States
Bartholomaus, T.C.; Institute for Geophysics, University of Texas, Austin, United States ; Department of Geology, University of Texas, Austin, United States
Felikson, D.; Institute for Geophysics, University of Texas, Austin, United States ; Department of Geology, University of Texas, Austin, United States
Stearns, L.A.; Department of Geology, University of Kansas, Lawrence, United States
Noël, Brice ; Université de Liège - ULiège > Département de géographie > Climatologie et Topoclimatologie ; Institute for Marine and Atmospheric Research Utrecht, Utrecht University, Utrecht, Netherlands
van den Broeke, M.R.; Institute for Marine and Atmospheric Research Utrecht, Utrecht University, Utrecht, Netherlands
Language :
English
Title :
The impact of glacier geometry on meltwater plume structure and submarine melt in Greenland fjords
NASA - National Aeronautics and Space Administration UO - University of Oregon
Funding text :
This work was partially supported by the National Aeronautics and Space Administration grant NNX12AP50G and the University of Oregon. M.R. van den Broeke and B.P.Y. Noël acknowledge financial support from the Polar Program of the Netherlands Organization for Scientific Research (NWO) and the Netherlands Earth System Science Center. T. Moon acknowledges support from the NSF OCE Postdoctoral Fellowship. We thank two anonymous reviewers for their thoughtful and constructive criticism of this work. Data used in this work are available by e-mailing the corresponding author.
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