Gravity-derived bathymetry for the Thwaites, Crosson and Dotson ice shelves (2009-2019) ...

• Main Authors: Jordan, Tom, Porter, David, Tinto, Kirsty, Millan, Romain, Muto, Atsuhiro, Hogan, Kelly, Larter, Robert, Graham, Alastair, Paden, John, Robinson, Carl
• Format: Dataset
• Language: English
• Published: UK Polar Data Centre, Natural Environment Research Council, UK Research & Innovation 2020
• Subjects: "EARTH SCIENCE","CRYOSPHERE","GLACIERS/ICE SHEETS"; "EARTH SCIENCE","OCEANS","BATHYMETRY/SEAFLOOR TOPOGRAPHY"; "EARTH SCIENCE","SOLID EARTH","GRAVITY/GRAVITATIONAL FIELD"; Bathymetry; Gravity; Ice shelf; Thwaites Glacier; West Antarctica; Antarctic; Antarc*; Antarctica; British Antarctic Survey; Ice Sheet; Ice Shelf; Ice Shelves
• Online Access: https://dx.doi.org/10.5285/7803de8b-8a74-466b-888e-e8c737bf21ce; https://data.bas.ac.uk/full-record.php?id=GB/NERC/BAS/PDC/01332

This dataset is an estimate of sub ice shelf bathymetry beneath the Thwaites, Crosson and Dotson ice shelves. The output bathymetry is derived from a new compilation of gravity data collected up to the end of the 2018/19 field season. The input gravity dataset includes airborne data from Operation Ice Bridge (OIB) and the NERC/NSF International Thwaites Glacier Collaboration (ITGC), and marine gravity from the R/V Nathaniel B. Palmer cruise NBP19-02. The recovered bathymetry was constrained by swath bathymetry and onshore airborne radio-echo depth sounding data in the surrounding area. Ice shelves mask the critical link between the ocean and cryosphere systems, and hence accurate sub ice shelf bathymetry is critical for generating reliable models of future ice sheet change. Included in the data release is the input free air gravity data, constraining bathymetry/sub-ice topography, and output gravity derived bathymetry. This work was funded by the British Antarctic Survey core program (Geology and Geophysics ... : Input gravity data is from Operation Ice Bridge (OIB) and the ITGC 2018/19 airborne campaign, together with marine gravity data from cruise NBP19-02. The OIB free-air gravity data has an error of ~1.67 mGal in this region and resolves anomalies with a ~10 km full wavelength (Cochran and Bell, 2010, updated 2018; Tinto and Bell, 2011). The ITGC campaign data (Jordan et al., 2020c) utilised a 'strapdown' gravity approach based around an iMar Inertial Navigation System (INS) (Becker et al., 2015; Wei and Schwarz, 1998), resulting in data with an internal error from crossover analysis of 1.56 mGal and resolving wavelengths down to ~5 km. Airborne data were restricted to lines flown at <1500 m above the surface with over 95% of the data collected at 450 m +/-200 m above the surface. Upward and downward continuation of the gravity data to a common altitude was therefore neglected as continuation by ~200 m will have little impact on the amplitude of the gravity anomalies (~1 mGal) given the ~1000 m range to the ...