Exploring Stability of Greenland’s Peripheral Marine-Terminating Glaciers through Analysis of Automated Terminus Position Timeseries

Abstract:

Changes in the position of marine glacier termini can strongly influence the stress balance that governs ice flow. Marine termini across the Arctic and Antarctic have retreated over the past two decades, resulting in widespread dynamic acceleration and mass loss. Yet, despite the important influence of terminus position on glacier stability, there have been few geographically-expansive studies that have investigated multi-year variations in terminus position with sub-annual temporal resolution due to the time-intensive nature of manual terminus mapping. Here we apply a newly-developed automated terminus mapping algorithm, which relies on the Wavelet Transform Modulus Maxima method to map intensity gradients in optical images, to a particularly under-studied region: Greenland’s peripheral glaciers and ice caps. The algorithm is applied to the full Landsat 8 record (2013-2020) to construct the first record of terminus change for the 641 marine-terminating glaciers spanning Greenland’s periphery. At broad spatial and temporal scales, we find both expected and unexpected terminus position change patterns based on a comparison with patterns observed for the ice sheet’s marine outlet glaciers. Our analysis represents the first in-depth analysis of terminus change for these glaciers and focuses not only on these broad patterns, but also on the inter-annual differences in terminus position change, which was not possible prior to the development of automated terminus mapping efforts.