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Continuum damage models for fracturing and weakening of Antarctic ice shelves

Presented by: 
Chris Borstad University Centre in Svalbard (UNIS)
Monday 4th December 2017 - 13:30 to 14:30
INI Seminar Room 1
Most of the Antarctic ice sheet drains to the ocean through floating ice shelves.  In many sectors of Antarctica, ice shelves are thinning due to oceanic or atmospheric warming, making them more susceptible to fracturing and even collapse.  Here I outline the different modes of ice shelf fracturing, including partial-thickness crevassing, through-thickness rifting, shear margin weakening, and the dominant mechanisms of iceberg calving. In the absence of a unifying damage framework capable of representing the diverse spatial and temporal scales of these mechanisms, I highlight two end-member damage models for particular cases.  The first is a fully elastic damage model, appropriate for representing the propagation of through-thickness rifts and tabular iceberg calving.  The second is a fully viscous damage model, appropriate for gradual weakening (especially in shear margins) of an ice shelf.  For the latter case, I present an adjoint-based inverse met hod for assimilating remote sensing data to infer a scalar damage variable over an ice shelf.  Results from a case study of the Larsen B ice shelf on the Antarctic Peninsula are used to inform the development of a damage evolution framework for application in ice sheet models.
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University of Cambridge Research Councils UK
    Clay Mathematics Institute London Mathematical Society NM Rothschild and Sons