Basal conditions of two Transantarctic Mountains outlet glac

Details of Research

TitleBasal conditions of two Transantarctic Mountains outlet glaciers from observation-constrained diagnostic modellingAbstractWe present a diagnostic glacier flowline model parameterized and constrained by new velocity data from ice-surface GPS installations and speckle tracking of TerraSAR-X satellite images, newly acquired airborne-radar data, and continental gridded datasets of topography and geothermal heat flux, in order to better understand two outlet glaciers of the East Antarctic ice sheet. Our observational data are employed as primary inputs to a modelling procedure that first calculates the basal thermal regime of each glacier, then iterates the basal sliding coefficient and deformation rate parameter until the fit of simulated to observed surface velocities is optimized. We find that the two glaciers have both frozen and thawed areas at their beds, facilitating partial sliding. Glacier flow arises from a balance between sliding and deformation that fluctuates along the length of each glacier, with the amount of sliding typically varying by up to two orders of magnitude but with deformation rates far more constant. Beardmore Glacier is warmer and faster-flowing than Skelton Glacier, but an up-glacier deepening bed at the grounding line, coupled with ice thicknesses close to flotation, lead us to infer a greater vulnerability of Skelton Glacier to grounding-line recession if affected by ocean-forced thinning and concomitant acceleration.AcknowledgementsFieldwork on Beardmore Glacier was supported by the United States Antarctic Program and Antarctica New Zealand, with assistance from Dean Arthur. Skelton Glacier fieldwork was supported by Antarctica New Zealand, with assistance from Rob McPhail, Stu Arnold and Hayden Short. Skelton Glacier radar data were collected and processed as a part of a test flight by CReSIS, TerraSAR-X data were received from the German Aerospace Center (DLR) through project HYD1421, and ASTER data were provided through the GLIMS project. Frank Pattyn kindly provided modelled basal temperature data. Brian Anderson and the anonymous reviewers are gratefully acknowledged for useful comments. This research was funded in part by the Ministry of Business, Innovation and Employment through research contract CO5X1001 to GNS Science.Funding DetailsMinistry of Business, Innovation and Employment; CO5X1001, MBIE, Ministry of Business, Innovation and Employment

Details

1st AuthorGolledge, N.AuthorGolledge, N.Marsh, O.Rack, W.Braaten, D.Jones, R.Year2014JournalJournal of GlaciologyVolume60Number223Pages855-866DOI10.3189/2014JoG13J131URLhttps://www.scopus.com/inward/recor.....032abfa130462817a7709043eKeywordsbasal iceglacierglacier flowglaciologyGPSice sheetice thicknessmodelingradarsatellite imagery, rank5Author KeywordsAntarctic glaciologyGlacier flowGlacier modellingIce dynamicsIce-sheet modelling

Other

TypeArticleCitationGolledge, N., Marsh, O., Rack, W., Braaten, D. and Jones, R. (2014). Basal conditions of two Transantarctic Mountains outlet glaciers from observation-constrained diagnostic modelling. Journal of Glaciology, 60(223): 855-866 IdentifierGolledge2014basalRelevancerank5