糖心视频

Thwaites Glacier in West Antarctica鈥攐ften called the "Doomsday Glacier"鈥攊s one of the fastest-changing ice鈥搊cean systems on Earth, and its future remains a major uncertainty in global sea-level rise projections. One of its floating extensions, the Thwaites Eastern Ice Shelf (TEIS), is partially confined and anchored by a pinning point at its northern terminus.

Over the last two decades, TEIS has experienced progressive fracturing around a prominent shear zone upstream of this pinning point.

A published in the Journal of Geophysical Research: Earth Surface provides comprehensive details on how progressive disintegration has been taking place over the last two decades.

The study was published by the Center for Earth Observation Sciences and led by Debangshu Banerjee, a recent graduate student from the Center for Earth Observation Science (CEOS), together with Dr. Karen Alley (Assistant Professor, CEOS) and Dr. David Lilien (Assistant Professor, Indiana University Bloomington and former Research Associate at CEOS).

Tracking fractures and ice shelf weakening

The research is part of the TARSAN (Thwaites-Amundsen Regional Survey and Network) project, one of the components of the International Thwaites Glacier Collaboration (ITGC)鈥攁 major U.S.鈥揢.K. research initiative studying the processes driving change in the Thwaites Glacier of West Antarctica. Renowned glaciologists Dr. Ted Scambos, Dr. Martin Truffer, Dr. Adrian Luckman, and Dr. Erin Pettitt have also been a part of this research.

Drawing on two decades (2002鈥�2022) of satellite imagery, ice-flow velocity measurements, and in-situ GPS records, the team traced the evolution of fractures within the TEIS shear zone and their connection to changes in ice dynamics. The analysis revealed that the gradual development of these fractures led to the shelf's progressive detachment from its pinning point, causing accelerated flow upstream and a loss of mechanical stability.

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The study identifies four distinct stages in this weakening process and offers two key insights. First, the fractures developed in two phases: an initial propagation of long, flow-parallel fractures, followed by shorter fractures oriented perpendicular to the direction of ice flow.

Second, the researchers found evidence for a positive feedback mechanism between fracture-induced damage and ice acceleration鈥攁n amplifying cycle that hastened the shelf's disintegration in recent years.

The research highlights how the pinning point, once a major stabilizing force for the TEIS, has gradually transitioned into a destabilizing agent through four distinct stages. This pattern of ice-shelf disintegration may serve as a warning for other Antarctic ice shelves that are currently showing similar signs of weakening.

The continued loss of these floating ice shelves could have significant implications for the Antarctic Ice Sheet's future contribution to global sea-level rise.