Ice Damage/Fracturing
Ice Damage/Fracturing
The speed at which the glaciers of the Antarctic Ice Sheet flow, and hence the rate at which ice is discharged into the ocean, depends on the geometry of the ice sheet and the material properties of the ice. The development of fractures has a significant effect on both of these components of the system and is therefore of crucial importance to understanding the dynamics and future evolution of the ice sheet. For example, fracturing introduces a nonlinearity into the system that is not well understood but could have significant consequences for the ice sheet, especially when fracturing occurs in the margins of ice shelves that provide buttressing to the upstream grounded ice. Additionally, surface crevasses can pre-condition ice shelves for disintegration via hydrofracture, can influence the surface energy balance of the ice sheet, and are a source of surface-to-bed hydrological pathways on grounded ice. Developing a proper understanding of these processes and how they interact requires large-scale acquisition of data on the extent and character of crevasses across the Antarctic Ice Sheet and the evolution of these in time.
Composite Sentinel-1 SAR image over the Amundsen Sea Embayment from June 2021 (a) and associated 50m resolution crevasse map (b) adapted from Surawy-Stepney et al. (2023b).
Summary of the fracture datasets planned within 5DAIS:
- In 5DAIS we will expand upon the methods detailed in Surawy-Stepney et al., 2023a and Surawy-Stepney et al., 2023b to extract maps of fractures over the majority of the Antarctic margin.
- These methods use a combination of deep learning and classical computer vision techniques along with advanced filtering and mosaicking to extract crevasse features from radiometrically terrain corrected synthetic aperture radar imagery collected by ESA/EC’s Sentinel-1 satellites at 50m spatial resolution.
- We will further develop the methods of detecting changes to the structural integrity of ice shelves by looking for trends in fracture and apply this procedure around the continent to determine spatial distribution of structural change.