Inferred Ice Stiffness/Strength

Inferred Ice Stiffness/Strength

The external driving forces applied to the Antarctic Ice Sheet by gravity and buoyancy are balanced by a mixture of viscous stresses and drag on the ice sheet base. The relative importance of these components of the force budget are determined by how slippery the interface between the ice sheet and the bed is, and the stiffness of the ice. The stiffness is a function principally of temperature, with temperate ice being more fluid than colder ice. However, stiffness is also affected by crystal grain size, the presence of macroscopic fabrics in the ice, and the presence of voids caused by fracturing. Understanding the present stiffness of ice across Antarctica, as well as the dominant mechanisms by which changes in stiffness occur is essential for reliably simulating the future evolution of the ice sheet.

Stiffness over the Larsen-C Ice Shelf at different assumed englacial temperatures – adapted from Borstad et al., 2013.

Summary of the inferred ice stiffness dataset planned within 5DAIS:

• Continent-wide englacial stiffness inferred from velocity data, acquired using feature-tracking applied to Sentinel-1 SAR imagery and the BISICLES ice sheet model (Cornford et al., 2013).
• Make use of a new, more accurate 3D temperature field, and fracture and strain-rate data from satellite observations for priors in the ice stiffness calculation.