Grounding-zone ice thickness from InSAR: Inverse modelling o
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TitleGrounding-zone ice thickness from InSAR: Inverse modelling of tidal elastic bendingAbstractIce-thickness measurements in Antarctic ice-shelf grounding zones are necessary for calculating the mass balance of individual catchments, but remain poorly constrained for most of the continent. We describe a new inverse modelling optimization approach to estimate ice thickness in the grounding zone of Antarctic outlet glaciers and ice shelves using spatial patterns of tide-induced flexure derived from differential interferometric synthetic aperture radar (InSAR). We demonstrate that the illposedness of the inverse formulation of the elastic-plate equations for bending can be controlled by regularization. In one dimension, the model recreates smooth, synthesized profiles of ice thickness from flexure information to within 1-2%. We test the method in two dimensions and validate it in the grounding zone of Beardmore Glacier, a major outlet glacier in the Transantarctic Mountains, using interferograms created from TerraSAR-X satellite imagery acquired in 2012. We compare our results with historic and modern ice-thickness data (radio-echo sounding from 1967 and ground-penetrating radar from 2010). We match both longitudinal and transverse thickness transects to within 50m rootmean-square error using an effective Young's modulus of 1.4GPa. The highest accuracy is achieved close to the grounded ice boundary, where current estimates of thickness based on surface elevation measurements contain a systematic bias towards thicker ice.AcknowledgementsWe thank Charles Swithinbank for information pertaining to the 1967 Beardmore Glacier RES data, and Antarctic New Zealand Event K001B-Ice and Dean Arthur for field and logistical support. This research was funded, in part, by the Ministry of Business, Innovation and Employment, through research contract CO5X1001 to GNS Science. TerraSAR-X data were provided by DLR from science proposal HYD1421. ASTER data were provided through the Global Land Ice Measurements from Space (GLIMS) project. Comments from Helen Amanda Fricker and three anony- mous reviewers led to substantial revisions and improvement of the paper.
1st AuthorMarsh, O.AuthorMarsh, O.Rack, W.Golledge, N.Lawson, W.Floricioiu, D.Year2014JournalJournal of GlaciologyVolume60Number221Pages526-536DOI10.3189/2014JoG13J033URLhttps://www.scopus.com/inward/recor.....4577038f3dfde782db383861aKeywordsaccuracy assessmentglacier mass balanceground penetrating radarice shelfice thicknessice-ocean interactioninterferometryinverse analysismodel testmodel validationremote sensingsatellite imagerysynthetic aperture radarTerraSAR-XYoung modulus, AntarcticaBeardmore GlacierEast AntarcticaTransantarctic Mountains, rank5Author KeywordsAntarctic glaciologyGlacier dischargeIce/ocean interactionsRemote sensing
TypeArticleCitationMarsh, O., Rack, W., Golledge, N., Lawson, W. and Floricioiu, D. (2014). Grounding-zone ice thickness from InSAR: Inverse modelling of tidal elastic bending. Journal of Glaciology, 60(221): 526-536 doi:10.3189/2014JoG13J033
Antarctica NZ (26th Nov 2018). Grounding-zone ice thickness from InSAR: Inverse modelling o . In Website Antarctica NZ. Retrieved 18th Jan 2021 13:43, from https://adam.antarcticanz.govt.nz/nodes/view/63647