Recent ice dynamics of outlet glaciers in Enderby Land, Kemp Land and Dronning Maud Land, East Antarctica, and their links to ocean-climate forcings between 1960s and 2024

Abstract

The East Antarctic Ice Sheet (EAIS) holds the largest potential contribution to
global sea-level rise—approximately→ 53 m—yet its outlet glaciers display pro-
nounced regional heterogeneity in both past behaviour and future vulnerability.
Observations and numerical models alike have shown that while some sectors of the EAIS are losing mass, others remain stable or even gain mass, raising questions about which regions may be most susceptible to continued warming.

To address this, the present thesis combines multi-decadal (1960s–2023) satellite remote sensing with statistical analysis to examine terminus behaviour across 44 marine-terminating glaciers in Enderby Land, Kemp Land, and Dronning Maud Land (DML). The regional assessment across Enderby and Kemp Land revealed that between the 1970s and 1988, reduced sea-ice cover drove widespread retreat; this pattern reversed from 1988 to 2000 as cooler ocean conditions and higher sea-ice concentrations, associated with a positive phase of the Southern Annular Mode, promoted glacier advance. Since 2000, however, the fraction of advancing glaciers has declined modestly. Furthermore, the terminus behaviour across individual glaciers was asynchronous, underscoring the influence of local, glacier-specific
controls alongside ocean-climatic drivers.

Statistical correlations between terminus-position change and ocean–climate drivers further underscore this heterogeneity. Across the study regions, higher seasonal sea-ice concentrations are generally associated with glacier advanc, that is, terminus positions tend to advance when sea-ice cover increases (positive correlation coefficients, typically ranging from +0.3 to +0.7). In contrast, elevated subsurface ocean temperatures correlate with glacier retreat (negative correlation coe!cients, often between –0.2 and –0.6). Nevertheless, the precise strength and direction of these relationships di”er substantially among individual glaciers. While some glaciers exhibited positive moderate correlations with sea-ice conditions, others exhibited negative moderate correlations with ocean warming. This variability highlighted the critical role of local factors such as fjord geometry, ice-shelf thickness, and grounding-line depth in modulating each glacier’s ocean-climatic response.

To examine some of these processes in more detail, two case studies focussed on Wilma–Robert–Downer (WRD) system in Kemp Land and Jutulstraumen in DML. These illustrate contrasting calving dynamics mediated by rift propagation. At WRD, rifts repeatedly nucleate in the same sector, advance with the ice tongue, and spawned major calving events in 1991 and 2003 (and a smaller event in 2014); persistent sea-ice and m´elange within rift cavities have, however, mitigated calving severity and facilitated subsequent advance. By contrast, Jutulstraumen’s floating tongue has hosted long-lived, slowly propagating rifts since the 1960s, enabling uninterrupted advance since its last major calving in 1967 stabilised by topographic pinning and cold waters, though recent warm-water incursions suggest rising vulnerability.

In contrast to the persistent mass losses of Greenland, West Antarctica and parts of the EAIS, majority of these EAIS outlet glaciers demonstrate net stability or advance on annual to decadal timescales, punctuated by episodic retreat. Local geomorphological and oceanic factors - fjord geometry, ice-shelf buttressing, and pinning points emerge as critical stabilising influences, highlighting the non-uniform sensitivity of EAIS glaciers to both regional climate variability and site-specific controls.