A Century of Stability of Avannarleq and Kujalleq Glaciers, West Greenland, Explained Using High‐Resolution Airborne Gravity and Other Data

• Main Authors: An, L, Rignot, E, Mouginot, J, Millan, R
• Format: Article in Journal/Newspaper
• Language: unknown
• Published: eScholarship, University of California 2018
• Subjects: Climate Action; Life Below Water; Greenland; bathymetry; gravity; mass balance; remote sensing; Meteorology & Atmospheric Sciences; Kujalleq; Avannarleq; Sermeq Avannarleq
• Online Access: https://escholarship.org/uc/item/1551d4q2

The evolution of Greenland glaciers in a warming climate depends on their depth below sea level, flow speed, surface melt, and ocean-induced undercutting at the calving front. We present an innovative mapping of bed topography in the frontal regions of Sermeq Avannarleq and Kujalleq, two major glaciers flowing into the ice-choked Torssukatak Fjord, central west Greenland. The mapping combines a mass conservation algorithm inland, multibeam echo sounding data in the fjord, and high-resolution airborne gravity data at the ice-ocean transition where other approaches have traditionally failed. We obtain a reliable, precision (±40m) solution for bed topography across the ice-ocean boundary. The results reveal a 700m deep fjord that abruptly ends on a 100-300m deep sill along the calving fronts. The shallow sills explain the presence of stranded icebergs, the resilience of the glaciers to ocean-induced undercutting by warm Atlantic water, and their remarkable stability over the past century.