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:
- Multidecadal satellite images and ice shelf modeling experiments were
used to examine dynamic changes of Larsen C during 1963–2020
- Rift development near ice rises is a primary control on ice shelf
retreat and flow acceleration before the compressive arch is reached
- Capturing the time-varying effects of rifts on ice rigidity is needed
to make realistic simulations of future ice shelf change
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.