Shujie Wang1,2,3, Hongxing Liu4,5, Kenneth Jezek6, Richard B. Alley2,7, Lei Wang8, Patrick Alexander9, and Yan Huang5
1Department of Geography, Pennsylvania State University, University Park, PA 16802, USA.
2Earth and Environmental Systems Institute, Pennsylvania State University, University Park, PA 16802, USA.
3Institute for Computational and Data Sciences, Pennsylvania State University, University Park, PA 16802, USA.
4Department of Geography, University of Alabama, Tuscaloosa, AL 35487, USA.
5Key Laboratory of Geographic Information Science, Ministry of Education, East China Normal University, Shanghai 200241, China.
6School of Earth Sciences, Ohio State University, Columbus, OH 43210, USA.
7Department of Geosciences, Pennsylvania State University, University Park, PA 16802, USA.
8Department of Geography & Anthropology, Louisiana State University, Baton Rouge, LA 70803, USA.
9Lamont-Doherty Earth Observatory, Columbia University, Palisades, NY 10964, USA.
Corresponding author: Shujie Wang (skw5660@psu.edu)
Key Points:
Abstract
Rapid retreat of the Larsen A and B ice shelves has provided important clues about the ice shelf destabilization processes. The Larsen C Ice Shelf, the largest remaining ice shelf on the Antarctic Peninsula, may also be vulnerable to future collapse in a warming climate. Here, we utilize multi-source satellite images collected over 1963–2020 to derive multidecadal time series of ice front, flow velocities, and critical rift features over Larsen C, with the aim of understanding the controls on its retreat. We complement these observations with modeling experiments using the Ice-sheet and Sea-level System Model to examine how front geometry conditions and mechanical weakening due to rifts affect ice shelf dynamics. Over the past six decades, Larsen C lost over 20% of its area, dominated by rift-induced tabular iceberg calving. The Bawden Ice Rise and Gipps Ice Rise are critical areas for rift formation, through their impact on the longitudinal deviatoric stress field. Mechanical weakening around Gipps Ice Rise is found to be a primary control on localized flow acceleration, leading to the propagation of two rifts that caused a major calving event in 2017. Capturing the time-varying effects of rifts on ice rigidity in ice shelf models is essential for making realistic predictions of ice shelf flow dynamics and instability. In the context of the Larsen A and Larsen B collapses, we infer a chronology of destabilization processes for embayment-confined ice shelves, which provides a useful framework for understanding the historical and future destabilization of Antarctic ice shelves.