Seismic reflection soundings of ice thickness and seabed depth were acquired on the Larsen C Ice Shelf in order to test a sub-shelf bathymetry model derived from the inversion of IceBridge gravity data. A series of lines were collected, from the Churchill Peninsula in the north to the Joerg Peninsula in the south, and also towards the ice front. Sites were selected using the bathymetry model derived from the inversion of free-air gravity data to indicate key regions where sub-shelf oceanic circulation may be affected by ice draft and sub-shelf cavity thickness. The seismic velocity profile in the upper 100 m of firn and ice was derived from shallow refraction surveys at a number of locations. Seismic velocities in the water column were derived from previous in situ measurements. Uncertainties in ice and water cavity thickness are in general < 10 m. Compared with the seismic measurements, the root-mean-square error in the gravimetrically derived bathymetry at the seismic sites is 162 m. The seismic profiles prove the non-existence of several bathymetric features that are indicated in the gravity inversion model, significantly modifying the expected oceanic circulation beneath the ice shelf. Similar features have previously been shown to be highly significant in affecting basal melt rates predicted by ocean models. The discrepancies between the gravity inversion results and the seismic bathymetry are attributed to the assumption of uniform geology inherent in the gravity inversion process and also the sparsity of IceBridge flight lines. Results indicate that care must be taken when using bathymetry models derived by the inversion of free-air gravity anomalies. The bathymetry results presented here will be used to improve existing sub-ice shelf ocean circulation models.

We present three new gridded bathymetric compilations of Sheldon Cove, Borgen Bay and Marian Cove. These bathymetry grids were compiled from EM122 multibeam swath bathymetry data acquired during three different cruises (RRS James Clark Ross JR17001, JR18003 and JR19002 cruises also known as NERC- ICEBERGS cruises) from 2017 to 2020. The data is available as grids of 5 m resolution in NetCDF and GeoTIFF formats using geographic coordinates on the WGS84 datum. This grid was compiled as part of the ICEBERGS (Impacts of deglaciation on bentic marine ecosystems in Antarctica) project. Funding was provided by the NERC grant NE/P003087/1.

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.

On cruise JR157 the Isis ROV was deployed on 15 dives in the Marguerite Trough area in January and February 2007. We present here the data acquired during dives 10 and 11. Dives 10 and 11 targeted a bedrock channel system on the inner continental shelf to investigate channel incision processes and the history of glaciation in the area. The plan was to map parts of the channel walls and thalweg, and then to use these data to locate the best coring sites within the channel system. In reality, several small patches of bathymetric data were acquired from the channels by a multibeam echosounder mounted on the ROV. This research was funded by UK Natural Environment Research Council grant AFI06/14 (NE/C506372/1) to J.A. Dowdeswell, R.D. Larter and G. Griffiths.

We present a new gridded bathymetric compilation around Tristan da Cunha here defined by the following bounding box: 5 to 16.8W, 33 to 43.5S. This bathymetry grid was compiled from a variety of multibeam swath bathymetry data acquired during 7 different cruises (see lineage). The data is available as a grid of 0.001 degrees resolution in three different formats: NetCDF, ArcView ASCII and GeoTIFF formats using geographic coordinates on the WGS84 datum. This grid is an output of the UK FCDO ''Blue Belt'' program and the following Natural Environment Research Council (NERC) BAS-ODA fundings: NE/R000107/1 and NE/T012439/1.

We present a new bathymetric compilation of the South Shetland Islands here defined by the following bounding box: 63 to 53.3 W, 63.5 to 60.5 S. This bathymetry grid was compiled from a variety of multibeam swath bathymetry data acquired during 76 different cruises (see lineage). The data is available as a grid of approximately 100 m resolution in two different formats: a GMT-compatible (2-D) NetCDF and Arc/Info and ArcView ASCII grid format using geographic coordinates on the WGS84 datum.

We present two new gridded bathymetric compilations of the Orkney Passage, Scotia Sea here defined by the following bounding boxes: 39.1 to 39.6 W, 60.55 to 60.7 S and 41.7 to 42.6 W, 60.45 to 60.8 S. These bathymetry grids were compiled from a variety of multibeam swath bathymetry data acquired during 12 different cruises (see lineage). The data is available as grids of 50 m resolution in a GMT-compatible (2-D) NetCDF format using geographic coordinates on the WGS84 datum. This grid was compiled in support of the ongoing monitoring efforts in and around Orkney Passage as part of the Ocean Regulation of Climate by Heat and Carbon Sequestration and Transports (ORCHESTRA) programme and preceding BAS NC projects, and the Dynamics of the Orkney Passage Outflow (DynOPO) project. Funding was provided by the NERC grants NE/K012843/1 and NE/N018095/1 as well as national capability

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.

We present a bathymetric compilation of Ryder Bay here defined by the following bounding box: 68.48 to 68W, 67.7 to 67.46S. This bathymetry grid was compiled from a variety of multibeam swath bathymetry data acquired during 18 different cruises (see lineage) undertaken by the RRS James Clark Ross. The data is available as a grid of 0.0005 degrees resolution in two different formats: a GMT-compatible (2-D) NetCDF and Arc/Info and ArcView ASCII grid format using geographic coordinates on the WGS84 datum.

Bathymetric compilation of the Brunt sub Ice Shelf, East Antarctic Ice Sheet. The bathymetry grid was compiled from a variety of different sources including multibeam swath bathymetry collected from scientific cruises undertaken by British Antarctic Survey (BAS) and Alfred Wegener Institute (AWI). Multibeam data were supplemented with regional bathymetry from the International Bathymetric Chart of the Southern Ocean (IBSCO) and seismic data. The data is available as a 500m resolution grid using the IBSCO polar stereographic projection. For further information regarding the creation of this dataset please refer to https://doi.org/10.5194/tc-12-2383-2018.