A constitutive framework for predicting weakening and reduced buttressing of ice shelves based on observations of the progressive deterioration of the remnant Larsen B Ice Shelf

摘要: Geophysical Research Letters RESEARCH LETTER 10.1002/2015GL067365 Key Points: • Assimilated observations indicate pro- gressive weakening of ice shelf from 2000 to 2015 New framework introduced for vis- cous deformation with analytical solution damage reproduces observed and is generalizable any Supporting Information: Information S1 Correspondence to: C. Borstad, chris.borstad@unis.no Citation: C., A. Khazendar, B. Scheuchl, M. Morlighem, E. Larour, Rignot (2016), A constitutive frame- work predicting reduced buttressing shelves based on the progressive deterioration remnant Larsen B Ice Shelf, Geophys. Res. Lett., 43, 2027–2035, doi:10.1002/2015GL067365. Received 9 DEC Accepted FEB 2016 article online 11 Published 4 MAR Shelf Chris Borstad 1 , Ala Khazendar 2 Bernd Scheuchl 3 Mathieu Morlighem Eric Larour 2,3 Department Arctic Geophysics, University Centre in Svalbard, Longyearbyen, Norway, Jet Propulsion Laboratory, California Institute Technology, Pasadena, California, USA, Earth System Science, Irvine, USA Abstract The increasing contribution Antarctic Sheet sea level rise linked reductions buttressing, driven large part by basal melting shelves. These ocean-driven losses are being compounded as weaken fracture. To date, model projections sheet evolution have not accounted Here we present first that explicitly includes mechanical weakening, degradation 2015. We implement this an able reproduce most shelf. In addition new opens door improved understanding predictions iceberg calving, meltwater routing hydrofracture, collapse. 1. Introduction Many largest fastest changes over last decade been thinning loss a manner consistent, at least qualitatively, notions [Intergovernmental Panel Climate Change, 2013]. predict fate sheet, therefore, dominant physical mechanisms must be accurately represented mod- els. Ocean-driven [Pritchard et al., 2012; 2013] believed predominant cause losses. However, thin they also become more suscep- tible fracture [Shepherd 2003]. West Antarctica, fracturing shear margins appears compounding associated [MacGregor 2012]. irreversible collapse Sheet, which speculated already underway [Rignot 2014; Joughin 2014], may hastened combined effects Yet fracture-induced poorly under- stood still absent evolution. Although advances ice-ocean coupling [Goldberg Hellmer 2012] providing insight into feedbacks warming oceans, models failing capture bulk rheology due address need, assemble longest available time series date weakening. then devise formalism consistent represent other glaciological processes involving fractures. focus here (RLBIS, Figure 1a), surviving portion filled embayment prior its partial 2002. provided RLBIS diminished period 2010 [Khazendar 2015], has facilitated acceleration tributary glaciers [Scambos 2015]. ©2016. American Union. All Rights Reserved. BORSTAD ET AL. Using remote sensing assimilated Model (ISSM) [Larour 2012], calculate spatial pattern years 2000, 2006, 2010, (Figure 1). analyze CONSTITUTIVE FRAMEWORK FOR ICE WEAKENING