Basin-scale partitioning of Greenland ice sheet mass balance components (2007-2011)

• Published in: Earth and Planetary Science Letters
• Main Authors: Andersen, M.L., Stenseng, Lars, Skourup, Henriette, Colgan, W., Khan, Shfaqat Abbas, Kristensen, Steen Savstrup, Andersen, S. B., Box, J.E., Ahlstrøm, A. P., Fettweis, X., Forsberg, René
• Format: Article in Journal/Newspaper
• Language: English
• Published: 2015
• Subjects: Airborne survey; Flux gate; Greenland ice sheet; Ice discharge; Mass loss partition; Surface mass balance; Climate models; Glacial geology; Glaciers; Sea level; Surveys; Airborne surveys; Ice discharges; Mass loss; Ice; /dk/atira/pure/sustainabledevelopmentgoals/climate_action; name=SDG 13 - Climate Action; Greenland; Ice Sheet
• Online Access: https://orbit.dtu.dk/en/publications/e1205d0d-6e8c-45a8-94d8-c69ed8aa7928; https://doi.org/10.1016/j.epsl.2014.10.015

The current deficit in Greenland ice sheet mass balance is due to both a decrease in surface mass balance (SMB) input and an increase in ice discharge (D) output. While SMB processes are beginning to be well captured by observationally-constrained climate modeling, insight into D is relatively limited. We use InSAR-derived velocities, in combination with ice thickness observations, to quantify the mass flux (F) across a flux perimeter around the ice sheet at ~1700 m elevation. To quantify D, we correct F for SMB, as well as changes in volume due to ice dynamics, in the area downstream of the gate. Using a 1961-1990 reference climatology SMB field from the MAR regional climate model, we quantify ice sheet mass balance within eighteen basins. We find a 2007-2011 mean D of 515±57 Gtyr-1. We find a 2007-2011 mean total mass balance of -262±21 Gtyr-1, which is equal to a 0.73 mm yr-1 global sea level rise contribution. This mass loss is dominated by SMB, which accounts for 61% of mass loss in the basins where partitioning is possible.