Aeromagnetic data provides important constraints on the sub-surface geology of a region. This dataset contains aeromagnetic line data collected by the British Antarctic Survey as part of the International Thwaites Glacier Collaboration (ITGC). Data were collected using a caesium magnetometer system, and have been corrected to total field values following the approach laid out by the SCAR ADMAP working group https://www.scar.org/science/admap/about/. Across flow flights were generally flown at a constant altitude ~450 m above the ice surface, but data was also collected along draped sections flown along the ice flow direction. In total 9872 km of data is presented, of this 6033 km was collected in the main survey area, while other data was collected on input transit flights. The aircraft used was the BAS aerogeophysicaly equipped twin otter VP-FBL. Data are available in ASCII file format (.xyz).

Aerogravity data has an important role to play in constraining sub-surface geology under grounded ice and bathymetry beneath floating ice shelves. This dataset contains aerogravity collected by the British Antarctic Survey as part of the International Thwaites Glacier Collaboration (ITGC). Data were collected using both a traditional stabilised platform approach, and a more modern strapdown gravity system. Flights were flown at a constant altitude ~450 m above the ice surface where surface topography was flat. Gravity data is also recovered along draped sections by the strapdown system. In total 9872 km of data is presented, of this 6033 km was collected in the main survey area, while other data was collected on input and output transit flights. The aircraft used was the BAS twin otter VP-FBL equipped for aerogeophysical surveys. Data are available in ASCII file format (.xyz). Three databases are provided with aerogravity data: one with the Strapdown processing flow, a second with the LaCoste & Romberg processing flow, and a final simplified database with the optimal free air gravity anomalies from the strapdown system.

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 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 in the open ocean, onshore airborne radio-echo depth sounding data and sub-shelf bathymetric observations from autonomous marine systems sent beneath the Dotson and Crosson Ice Shelves and seismic observations from the Crosson Ice Shelf surface. This bathymetric dataset supersedes the dataset of Jordan et al. 2020 (https://doi.org/10.5285/7803de8b-8a74-466b-888e-e8c737bf21ce ), as the new direct observations of sub-shelf bathymetry revealed the previously estimated depth of the basin beneath the Crosson and Dotson region to be ~400m too shallow. This inaccuracy is attributed to isostatic compensation of the deep basin, the mantle gravity effect of which was not considered in the original model. Included in the data release is the input free air gravity data, constraining bathymetry/sub-ice topography, isostatic gravity model, output gravity derived bathymetry including consideration of isostatic compensation which improves the fit to the new observed sub-shelf data and a final revised bathymetry dataset which incorporates the bathymetry from the gravity model with all bathymetric constraints. This work was funded by the Thwaites-Amundsen Regional Survey and Network Integrating Atmosphere-Ice-Ocean Processes (TARSAN) project, a component of the International Thwaites Glacier Collaboration (ITGC), from National Science Foundation (NSF: Grant 1929991) and Natural Environment Research Council (NERC: Grant NE/S006419/1)

We present here the airborne Lidar data was collected over the Thwaites Glacier catchment and adjacent ice shelves during the 2018/19 and 2019/20 field seasons. The data was collected using a Riegl Q240i-80 scanning system mounted in the BAS aerogeophysically equipped twin otter aircraft. It provides a high resolution (0.2 to 0.4 points per m2), and high accuracy (~10 cm vertical) georeferenced and time stamped swath of surface elevation information. Each track is ~600 m wide. Such data provides critical information about how the surface of the Thwaites Glacier system is changing. The Thwaites 2019/20 aerogeophysical survey was carried out as part of the BAS National Capability contribution to the NERC/NSF International Thwaites Glacier Collaboration (ITGC) program, with additional funding for LIDAR data processing from the UK Foreign and Commonwealth Office.

***** A new version of the dataset is available ***** Jordan, T., Heywood, K., Wahlin, A., Hall, R., Muto, A., Dutrieux, P., Hogan, K., Girton, J., Alley, K., & Pettit, E. (2025). Updated gravity-derived bathymetry for the Thwaites, Crosson and Dotson ice shelves (2009-2022) (Version 1.0) [Data set]. NERC EDS UK Polar Data Centre. https://doi.org/10.5285/baef2e88-300f-42bc-8ccb-bfdff147a492 ********************************************** 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 team), in support of the joint Natural Environment Research Council (NERC)/ National Science Foundation (NSF) International Thwaites Glacier Collaboration (ITGC). Additional specific support came from NERC Grants: NE/S006664/1 and NE/S006419/1, and NSF Grants: NSF1842064, NSFPLR-NERC-1738942, NSFPLR-NERC-1738992 and NSFPLR-NERC-1739003.