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.

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 map of changes in ice surface speed in metres/year for Thwaites Glacier, West Antarctica, between January 2012 and January 2021. Speeds based on feature tracking of satellite synthetic aperture radar data. The work was funded by NERC projects NE/P011365/1 and NE/S006605/1.

Polarimetric phase-sensitive radar measurements were collected at the Western Antarctic Ice Sheet (WAIS) Divide on the 25th and 26th December 2019. The measurements were conducted at 10 sites along a 6 km-long transect ~5-10 km northeast of the location of the WAIS Divide Deep Ice Core. At each site, a suite of four quadrature (quad-) polarimetric measurements were collected using an autonomous phase-sensitive radio echo sounder (ApRES) in a single-input single-output (SISO) configuration. The study is part of the Thwaites Interdisciplinary Margin Evolution (TIME) project of the International Thwaites Glacier Collaboration (ITGC), and is a collaboration between the United States National Science Foundation (NSF) and the United Kingdom Natural Environment Research Council (NERC). It was funded by UK Natural Environment Research Council (NERC) research grant NE/S006788/1 and USA National Science Foundation (NSF) research grant 1739027.

A time series of surface ice flow speed at a point on Thwaites Glacier, West Antarctica. The point is on grounded ice and is upstream of a sub-shelf cavity on the west flank of the fast-moving core of Thwaites Glacier. There are a total of 589 points. First column = yyyy-mm-dd, second column = speed in kilometres per year. The work was funded by NERC projects NE/P011365/1 and NE/S006605/1.

Two maps of surface elevation change for Thwaites Glacier, West Antarctica. Change is in metres between 2013-12-21 and 2017-07-11, and between 2017-07-11 and 2020-11-02. 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.

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.

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.