The impact of glacier geometry on meltwater plume structure and submarine melt in Greenland fjords

• Published in: Geophysical Research Letters
• Main Authors: Carroll, D., Sutherland, D.A., Hudson, B., Moon, T., Catania, G.A., Shroyer, E.L., Nash, J.D., Bartholomaus, T.C., Felikson, D., Stearns, L.A., Noël, Brice, van den Broeke, M.R.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Blackwell Publishing Ltd 2016
• Subjects: fjord; Greenland Ice Sheet; modeling; outlet glacier; physical oceanography; submarine melt; Equivalent depth; Glacier geometry; Ocean stratification; Plume structure; Upwelling plume; Geophysics; Earth and Planetary Sciences (all); General Earth and Planetary Sciences; Physical; chemical; mathematical & earth Sciences; Earth sciences & physical geography; Physique; chimie; mathématiques & sciences de la terre; Sciences de la terre & géographie physique; glacier; Greenland; Ice Sheet
• Online Access: https://orbi.uliege.be/handle/2268/301896; https://orbi.uliege.be/bitstream/2268/301896/1/Carroll_GRL_2016.pdf; https://doi.org/10.1002/2016GL070170

peer reviewed 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.