Revealing the former bed of Thwaites Glacier using sea-floor bathymetry: Implications for warm-water routing and bed controls on ice flow and buttressing ...

• Main Authors: Hogan, KA, Larter, RD, Graham, AGC, Arthern, R, Kirkham, JD, Rebecca L, T, Jordan, TA, Clark, R, Fitzgerald, V, Wählin, AK, Anderson, JB, Hillenbrand, CD, Nitsche, FO, Simkins, L, Smith, JA, Gohl, K, Erik Arndt, J, Hong, J, Wellner, J
• Format: Article in Journal/Newspaper
• Language: English
• Published: Copernicus GmbH 2020
• Subjects: 37 Earth Sciences; 3709 Physical Geography and Environmental Geoscience; 13 Climate Action; Thwaites Glacier; Antarc*; Ice Shelf; Sea ice
• Online Access: https://dx.doi.org/10.17863/cam.62674; https://www.repository.cam.ac.uk/handle/1810/315568

Abstract. The geometry of the sea floor immediately beyond Antarctica's marine-terminating glaciers is a fundamental control on warm-water routing, but it also describes former topographic pinning points that have been important for ice-shelf buttressing. Unfortunately, this information is often lacking due to the inaccessibility of these areas for survey, leading to modelled or interpolated bathymetries being used as boundary conditions in numerical modelling simulations. At Thwaites Glacier (TG) this critical data gap was addressed in 2019 during the first cruise of the International Thwaites Glacier Collaboration (ITGC) project. We present more than 2000 km2 of new multibeam echo-sounder (MBES) data acquired in exceptional sea-ice conditions immediately offshore TG, and we update existing bathymetric compilations. The cross-sectional areas of sea-floor troughs are under-predicted by up to 40 % or are not resolved at all where MBES data are missing, suggesting that calculations of trough capacity, and thus ...