A new subglacial bed Digital Elevation Model (DEM) from Ellsworth Subglacial Highlands (ESH) was created from previously gridded bed elevation data and new unpublished radar data. The new DEM includes the upper reaches of Pine Island Glacier, Rutford and Institute Ice Streams and reveals new topographical features. The main findings on this new DEM are two linear deep throughs with a perpendicular transection valley near Subglacial Lake Ellsworth. Additionally, using the new DEM and ice surface elevation data from CryoSat2 ice surface DEM, a hydropotential model was built and used to create a detailed hydropotential model of ESH to simulate the subglacial hydrological network. This approach allowed us to characterize basal hydrology, subglacial water catchments and connections between them. In this characterization we noticed the mismatch between subglacial hydrological catchment and ice surfaces catchment of Rutford Ice Stream, Pine Island Glacier and Thwaites Glacier. Funding was provided by NERC Antarctic Funding Initiative (AFI) grants NE/D008751/1, NE/D009200/1, and NE/D008638/1, and NERC grant NE/G013071/1.
This dataset contains measurements of snow accumulation over an 11-month period in 2016 at six sites in the Pine Island-Thwaites Glacier catchment of West Antarctica. The sites were visited on two occasions, the first in January 2016 and the second in December 2016. The accumulation rate at each site was calculated using an average density profile, based on a compilation of six low elevation sites on Pine Island Glacier (iSTAR sites 15-19, and 22; Morris et al., 2017) that are situated nearby. The average density for the top metre based on this compilation is 419 kg m-3. Further details are provided in the associated publication.
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.
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.
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.
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.
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.
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).
This dataset contains the position and depth of four spatially-extensive Internal Reflecting Horizons (or IRHs) traced on the British Antarctic Survey''s PASIN system and NASA Operation IceBridge''s MCoRDS2 system across the Pine Island Glacier catchment. Using the WAIS Divide ice-core chronology and a 1-D steady-state model, we assign ages to our four IRHs: (R1) 2.31-2.92 ka, (R2) 4.72 +/- 0.28 ka, (R3) 6.94 +/- 0.31 ka, and (R4) 16.50 +/- 0.79 ka. This project was funded by the UK Natural Environment Research Council Grant NE/L002558/1