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 during the second aerogeophysical survey carried out 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/). In total 8688 km of data is presented, of this ~6052 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 as an ASCII table (.csv). 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. Data processing was supported by the BAS Geology and Geophysics team.

As part of the International Thwaites Glacier Collaboration (ITGC) ~9540 km of new airborne gravity data was acquired by the British Antarctic Survey, including ~6200 km over the Thwaites Glacier catchment. Data was collected using an iCORUS strap-down airborne gravimeter system mounted on the BAS aerogeophysical equipped survey aircraft VP-FBL. The survey operated from Lower Thwaites Glacier camp, and focused on collecting data between 70 and 180 km from the grounding line. Additional profiles from the coast to the Western Antarctic Ice Sheet (WAIS) divide and over the eastern shear margin were also flown. Navigation, aircraft attitude, sensor temperature, initial and levelled free air gravity anomalies are provided as an ASCI table. 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. Data processing was supported by the BAS Geology and Geophysics team.

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.

Conductivity, Temperature and Depth (CTD) profiles were collected in the grounding zone region of Thwaites Glacier Eastern Ice Shelf in January 2020 as part of the International Thwaites Glacier Collaboration MELT project. Using a borehole deployable CTD system (SBE49), 15 profiles were collected over a period of 4 days between January 9th and January 12th to observe the hydrographic structure of the water column. The profiles extended from the ice base (520 dbar) to approximately 5 m above the seabed (575 dbar). Funding was provided by NSFPLR-NERC: Melting at Thwaites grounding zone and its control on sea level (THWAITES-MELT) NE/S006761/1.

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).

Variability in temperature, salinity and velocity was observed approximately 1.5 m beneath the base of Thwaites Glacier in the grounding zone region of the Eastern Ice Shelf as part of the International Thwaites Glacier Collaboration MELT project. Using a borehole deployable turbulence instrument cluster, the average temperature, salinity and velocity was observed over a 15-minute period every 2 hours. Funding was provided by NSFPLR-NERC: Melting at Thwaites grounding zone and its control on sea level (THWAITES-MELT) NE/S006761/1.

As part of the International Thwaites Glacier Collaboration (ITGC) 4432 km of new radar depth sounding data was acquired over the Thwaites Glacier catchment by the British Antarctic Survey. Data was collected using the PASIN polametric radar system, fitted on the BAS aerogeophysical equipped survey aircraft VP-FBL. The survey operated from Lower Thwaites Glacier camp, and focused on collecting data in regions of ice >1.5 km thick between 70 and 180 km from the grounding line. Additional profiles from the coast to the Western Antarctic Ice Sheet (WAIS) divide and over the eastern shear margin were also flown. Ice thicknesses between 418 and 3744 m were measured, with a minimum bed elevation of -2282 imaged. This dataset contains the navigation, surface elevation, ice thickness, and bed elevation data from the Thwaites Glacier 2019/20 season in the form of a CSV file. 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. Data processing was supported by the BAS Geology and Geophysics team.

We present a new compilation of multibeam-bathymetric data for the inner Amundsen Sea continental shelf beyond Thwaites and Pine Island glaciers (bounding box: 100W to 110W, 74S to 75.5S). The region includes Pine Island Bay, marine areas offshore the Thwaites Ice Shelf to the Crosson Ice Shelf, and covers an area of 74,750 km2. The bathymetric grids were compiled from all available multibeam echosounder (MBES) data acquired by UK, German, USA and Korean scientific cruises to the area between 1999 and 2019 (see lineage). Three grids of sea floor elevation data are available in a range of formats (ESRI ascii interchange format and GMT-compatible netCDF 4byte float): a 50-m resolution grid with no interpolation, a 50-m grid interpolated up to 300 m from cells with real data, and a 500-m resolution grid with no interpolation. Note that these grids have not been merged with regional bathymetric grids and, therefore, do not have continuous coverage (i.e. cells are only populated where multibeam data exist). This work was supported by grants from the National Science Foundation (NSF: Grant OPP- 1738942) and Natural Environment Research Council (NERC: Grant NE/S006664/1) as part of the International Thwaites Glacier Collaboration (ITGC) programme, and grants NE/J005770/1 and NE/J005703/1 as part of the iSTAR Programme.

Thwaites Glacier, West Antarctica. An animated time series plot of 64 profiles of ice base and surface elevation along a flowline based on the mean flow direction. The flowline passes through a region of large elevation change that took place between 2014 and 2017. The work was funded by NERC projects NE/P011365/1 and NE/S006605/1

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.