SERMeQ model produces a realistic upper bound on calving retreat for 155 Greenland outlet glaciers

Abstract

The rate of land ice loss due to iceberg calving is a key source of variability among model projections of the 21st century sea level rise. It is especially challenging to account for mass loss due to iceberg calving in Greenland, where ice drains to the ocean through hundreds of outlet glaciers, many smaller than typical model grid scale. Here, we apply a numerically efficient network flowline model (SERMeQ) forced by surface mass balance to simulate an upper bound on decadal calving retreat of 155 grounded outlet glaciers of the Greenland Ice Sheet-resolving five times as many outlets as was previously possible. We show that the upper bound holds for 91% of glaciers examined and that simulated changes in terminus position correlate with observed changes. SERMeQ can provide a physically consistent constraint on forward projections of the dynamic mass loss from the Greenland Ice Sheet associated with different climate projections.

Advances in data availability to constrain and evaluate frontal ablation of ice-dynamical models of Greenland's tidewater peripheral glaciers

“…We propose the use of the terminus positions mapped by Kochtitzky and Copland (2022) to identify glaciers with more than one terminus and correct this problem by manually subdividing the RGI outlines so there is only one terminus per RGI entity, or by testing these glaciers with new automatic centerline detection methods that are independent of topographic data. Ultee and Bassis (2020) have successfully applied a new centerline detection algorithm based on tracing ice surface velocities from terminus positions. This approach could be implemented in OGGM, by making use of Kochtitzky and Copland (2022) terminus positions and ITS_LIVE surface velocities.…”