Nicholas Rathmann: Recent advances made on modeling and observing ice rheology and fabric at the Niels Bohr Institute (Copenhagen)

Abstract:

The evolving material properties of glacier ice can exert significant control on the flow of glaciers and ice sheets, causing softening or hardening that varies by orders of magnitude. The crystal orientation fabric, in particular, is believed to facilitate the strong shear localization observed in the shear margins of ice streams and ice shelves, with relevance to continental-scale projections of ice-sheet mass loss. But modelling fabric development in dynamic areas far from ice-sheet divides, such as in ice streams and on ice shelves, remains largely unexplored due to computational expense and lack of useful fabric-compatible flow approximations. In this talk, I will present recent advances we have made in Copenhagen on modelling fabric development at large scale. This includes a new way to numerically represent fabric, to solve the coupled problem between fabric and flow, but also how we have been able to validate our models using state-of-art ice-penetrating radar.