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SUMMARY:Continuum damage models for fracturing and weakening of Antarctic 
 ice shelves - Chris Borstad (University Centre in Svalbard (UNIS))
DTSTART:20171204T133000Z
DTEND:20171204T143000Z
UID:TALK96037@talks.cam.ac.uk
CONTACT:INI IT
DESCRIPTION:Most of the Antarctic ice sheet drains to the ocean through fl
 oating ice shelves.&nbsp\; In many sectors of Antarctica\, ice shelves are
  thinning due to oceanic or atmospheric warming\, making them more suscept
 ible to fracturing and even collapse.&nbsp\; Here I outline the different 
 modes of ice shelf fracturing\, including partial-thickness crevassing\, t
 hrough-thickness rifting\, shear margin weakening\, and the dominant mecha
 nisms of iceberg calving. In the absence of a unifying damage framework ca
 pable of representing the diverse spatial and temporal scales of these mec
 hanisms\, I highlight two end-member damage models for particular cases.&n
 bsp\; The first is a fully elastic damage model\, appropriate for represen
 ting the propagation of through-thickness rifts and tabular iceberg calvin
 g.&nbsp\; The second is a fully viscous damage model\, appropriate for gra
 dual weakening (especially in shear margins) of an ice shelf.&nbsp\; For t
 he latter case\, I present an adjoint-based inverse met hod for assimilati
 ng remote sensing data to infer a scalar damage variable over an ice shelf
 .&nbsp\; Results from a case study of the Larsen B ice shelf on the Antarc
 tic Peninsula are used to inform the development of a damage evolution fra
 mework for application in ice sheet models.
LOCATION:Seminar Room 1\, Newton Institute
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