This data set contains a bed topography and bathymetry map of Greenland based on mass conservation, multi-beam data, and other techniques. It also includes surface elevation and ice thickness data, as well as an ice/ocean/land mask.

This upload contains the data which accompanies the manuscript: 'Antarctic subglacial topography mapped from space reveals complex mesoscale landscape dynamics'.

Metrics calculated for each of the 4269 50 km by 50 km regions

Datasets required for plotting

To plot the figures, you will either require the following datasets:

or, the figures can be regenerated using the following datasets, which are available at the listed DOIs

Warm water from the Southern Ocean has a dominant impact on the evolution of Antarctic glaciers and in turn on their contribution to sea level rise. Using a continuous time series of daily-repeat satellite synthetic-aperture radar interferometry data from the ICEYE constellation collected in March-June 2023, we document an ice grounding zone, or region of tidally-controlled migration of the transition boundary between grounded ice and ice afloat in the ocean, at the main trunk of Thwaites Glacier, West Antarctica, a strong contributor to sea level rise with an ice volume equivalent to a 0.6-m global sea level rise. The ice grounding zone is 6 km wide in the central part of Thwaites with shallow bed slopes, and 2 km wide along its flanks with steep basal slopes. We additionally detect irregular seawater intrusions, 5-10 cm in thickness, extending another 6 km upstream, at high tide, in a bed depression located beyond a bedrock ridge that impedes the glacier retreat. Seawater intrusions align well with regions predicted by the GlaDS subglacial water model to host a high-pressure distributed subglacial hydrology system in between lower-pressure subglacial channels. Pressurized seawater intrusions will induce vigorous melt of grounded ice over kilometers, making the glacier more vulnerable to ocean warming, and increasing the projections of ice mass loss. Kilometer-wide, widespread seawater intrusion beneath grounded ice may be the missing link between the rapid, past, and present changes in ice sheet mass and the slower changes replicated by ice sheet models. The dataset includes grounding line positions, all ICEYE radar interferograms and parameter files, files of tidal predictions and corrections for change in atmospheric pressure, and output products from the GlADS subglacial hydrology model. Methods Differential interferometry measures a differential change in ice displacement between 3 (or 4) epochs after eliminating the horizontal motion of ice through differencing of two pairs: we subtract two consecutive one-day pairs to eliminate the (steady) horizontal motion of the ice and leave the short term (vertical) motion of the ice, i.e. the vertical motion caused by changes in oceanic tide and atmospheric pressure, plus noise. If there is a data gap in data acquisition, we combine 2 x 1-day pairs acquired more than one day apart, hence 4 scenes. Predictions of SSH. We calculate changes in SHH using the CATS2008 tidal model corrected for IBE using ERA-5 atmospheric pressure fields.
Subglacial hydrology is reproduced using the 2D finite-element Glacier Drainage System (GlaDS) model, which predicts the presence of long, high-pressured subglacial channels and an adjacent distributed drainage system. GlaDS calculates water discharge, flux, and pressure beneath Thwaites Glacier. The model allows coincident development of distributed and channelized systems. We test a range of conductivity of the distributed and channelised systems to converge to a stable solution. We use outputs that produce a) an upper limit for water pressure, beyond which the model does not converge, b) a lower limit when solutions have water with pressures far below the overburden pressure, and c) intermediate levels of pressure. We present an output (c) with a distributed system conductivity of 1 x 10-4 m3/2 kg-1/2 and a channel conductivity of 5 x 10-2 m3/2 kg-1/2. The model is applied with basal sliding velocity and water production (geothermal and frictional heat) from the ISSM IMSIP-6 Antarctic control run along with surface and bed topographies from BedMachine Antarctica version 1. The model is run on a mesh of 19,340 nodes with refining near the grounding line giving a minimum edge length of 280 m. The model is run for 20,000 days until near steady state.

MAR dataset required to run MAR (boundary conditions, vegetation, topography).

Forcing files are only for a standard bench experiment over Antarctica forced by ERA-5 for 02/2015.

Licenses :

AntTOPO :

BedMachine_v02.nc3 : https://doi.org/10.5067/FPSU0V1MWUB6. Cite Morlighem, M. (2022). MEaSUREs BedMachine Antarctica, Version 3 [Data Set]. Boulder, Colorado USA. NASA National Snow and Ice Data Center Distributed Active Archive Center. https://doi.org/10.5067/FPSU0V1MWUB6. Date Accessed 01-26-2023.

When using this data product in a publication, please include the following citations in addition to the data product citation provided above: Morlighem, M., E. Rignot, T. Binder, D. D. Blankenship, R. Drews, G. Eagles, O. Eisen, F. Ferraccioli, R. Forsberg, P. Fretwell, V. Goel, J. S. Greenbaum, H. Gudmundsson, J. Guo, V. Helm, C. Hofstede, I. Howat, A. Humbert, W. Jokat, N. B. Karlsson, W. Lee, K. Matsuoka, R. Millan, J. Mouginot, J. Paden, F. Pattyn, J. L. Roberts, S. Rosier, A. Ruppel, H. Seroussi, E. C. Smith, D. Steinhage, B. Sun, M. R. van den Broeke, T. van Ommen, M. van Wessem, and D. A. Young. 2020. Deep glacial troughs and stabilizing ridges unveiled beneath the margins of the Antarctic ice sheet. Nature Geoscience. 13. DOI: 10.1038/s41561-019-0510-8.

ERA-5-ANT

Climate Data Store Copernicus -- Copernicus license; How to ancknowledge;

Acknowledgment section of the article may contain the following: Hersbach, H. et al., (2018) was downloaded from the Copernicus Climate Change Service (C3S) Climate Data Store. The results contain modified Copernicus Climate Change Service information 2020. Neither the European Commission nor ECMWF is responsible for any use that may be made of the Copernicus information or data it contains.

Bibliography may contain the following: Hersbach, H., Bell, B., Berrisford, P., Biavati, G., Horányi, A., Muñoz Sabater, J., Nicolas, J., Peubey, C., Radu, R., Rozum, I., Schepers, D., Simmons, A., Soci, C., Dee, D., Thépaut, J-N. (2018): ERA5 hourly data on single levels from 1959 to present. Copernicus Climate Change Service (C3S) Climate Data Store (CDS). (Accessed on 14-APR-2021), 10.24381/cds.adbb2d47

Throughout the content of the article, the dataset used maybe referred to as: Hersbach, H. et al., (2018)

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FAO: todo

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Geology is based on field work by Peter R. Dawes in 1971, 1975 and 1978, the latter year with Allen P. Nutman. Compiled with photointerpretation 1988–89, with local revision based on field work in 2001. Apart from northernmost Kangerlussuaq (Inglefield Bredning), the coast was surveyed by boat with sporadic foot traverses, aided by helicopter in 1978 and 2001. Geology of Qaqujaarsuaq (Smithson Bjerge) is based on simplification of the 1:50 000 map by Allen P. Nutman (1984). GIS compilation: Katja T. Walentin, Samuel P. Jackson, Eva Willerslev and Mette S. Jørgensen. Cross sections: Martin Sønderholm; Smithson Bjerge section is based on Nutman (1984). Editorial handling: Thomas F. Kokfelt and Martin Sønderholm. Reviewed by John Grocott (Durham University, United Kingdom) and Marc R. St-Onge (Geological Survey of Canada). Detailed information on the map units is available in the GEUS Greenland Intrusive and Stratigraphic Database using the GU-codes shown in brackets in the legend (https://doi.org/10.22008/FK2/F9MBNJ). Information on mineral occurrences is available in the Greenland Mineral Resources Portal (https://www.greenmin.gl). Topographic base: Geodetic Institute maps at 1:200 000 from 1954 with major revision of the ice margin and glaciers based on 1:150 000 aerial photographs from 1985–1987 and Sentinel 2 satellite scenes from 2019. All heights are in metres. Additional lake heights are from the Danish Agency for Data Supply and Infrastructure (now the Danish Agency for Climate Data): Højdemodel Grønland (https://dataforsyningen.dk/data/4780, accessed September 2023). Ground exposed by ice retreat since initial compilation in 1988–1989 is identified in the legend. 1949 ice margins are from Geodetic Institute maps. Ice margins recorded during expeditions by Robert E. Peary in 1892 and Lauge Koch in 1922 are approximate. Ice altimetry and thickness are based on data from Morlighem et al. (2017), bathymetry is from Morlighem et al. (2022). Authorised place names are from Oqaasileriffik (The Language Secretariat of Greenland), with supplementary names from Laursen (1972). Projection: WGS 84 UTM Zone 20N. Copyright © Geological Survey of Denmark and Greenland. References: Dawes, P.R. 1997: The Proterozoic Thule Supergroup, Greenland and Canada: history, lithostratigraphy and development. Geology of Greenland Survey Bulletin 174, 150 pp. https://doi.org/10.34194/ggub.v174.5025 Dawes, P.R. 2006: Explanatory notes to the Geological map of Greenland, 1:500 000, Thule, Sheet 5. Geological Survey of Denmark and Greenland Map Series 2, 97 pp. + map sheet. https://doi.org/10.34194/geusm.v2.4614 Laursen, D. 1972: The place names of North Greenland. Meddelelser om Grønland 180(2), 443 pp. + 18 plates. Morlighem, M. et al. 2017: BedMachine v3 [Surface; Thickness]: Complete bed topography and ocean bathymetry mapping of Greenland from multibeam echo sounding combined with mass conservation. Geophysical Research Letters 44, 11051–11061. https://doi.org10.1002/2017GL074954 Morlighem, M. et al. 2022: IceBridge BedMachine Greenland, Version 5 [Bed]. NASA National Snow and Ice Data Center Distributed Active Archive Center. https://doi.org/10.5067/GMEVBWFLWA7X (accessed January 2024). Nutman, A.P. 1984: Precambrian gneisses and intrusive anorthosite of Smithson Bjerge, Thule district, North-West Greenland. Rapport Grønlands Geologiske Undersøgelse 119, 31 pp. + plate. https://doi:10.34194/rapggu.v119.7849 Thomassen, B. & Krebs, J.D. 2004: Mineral exploration of selected targets in the Qaanaaq region, North-West Greenland: follow-up on Qaanaaq 2001. Danmarks og Grønlands Geologiske Undersøgelse Rapport 2004/42, 64 pp. https://doi.org/10.22008/gpub/25622 Thomassen, B., Krebs, J.D. & Dawes, P.R. 2002: Qaanaaq 2001: mineral exploration in the Olrik Fjord – Kap Alexander region, North-West Greenland. Danmarks og Grønlands Geologiske Undersøgelse Rapport 2002/86, 72 pp. + map. https://doi.org/10.22008/gpub/18491

Geology is based on field work by Peter R. Dawes in 1971, 1975 and 1978. Compiled with photointerpretation 1988–89, with local revision based on field work in 2001. The coast was surveyed by boat with sporadic foot traverses, aided by helicopter in 1978 and 2001. GIS compilation: Katja T. Walentin, Samuel P. Jackson, Eva Willerslev and Mette S. Jørgensen. Cross section: Martin Sønderholm. Editorial handling: Thomas F. Kokfelt and Martin Sønderholm. Reviewed by John Grocott (Durham University, United Kingdom) and Marc R. St-Onge (Geological Survey of Canada). Detailed information on the map units is available in the GEUS Greenland Intrusive and Stratigraphic Database using the GU-codes shown in brackets in the legend (https://doi.org/10.22008/FK2/F9MBNJ). Information on mineral occurrences is available in the Greenland Mineral Resources Portal (https://www.greenmin.gl). Topographic base: Geodetic Institute maps at 1:200 000 from 1954 with major revision of the ice margin and glaciers based on 1:150 000 aerial photographs from 1985–1987 and Sentinel 2 satellite scenes from 2019. All heights are in metres. Additional lake heights are from the Danish Agency for Data Supply and Infrastructure (now the Danish Agency for Climate Data): Højdemodel Grønland (https://dataforsyningen.dk/data/4780, accessed September 2023). Ground exposed by ice retreat since initial compilation in 1988–1989 is identified in the legend. 1949 ice margins are from Geodetic Institute maps. Ice margins recorded during expeditions by Robert E. Peary in 1892 and Lauge Koch in 1922 are approximate. Ice altimetry and thickness are based on data from Morlighem et al. (2017), bathymetry is from Morlighem et al. (2022). Landslides are modified from GEUS internal data, for methodology see Svennevig (2019). Authorised place names are from Oqaasileriffik (The Language Secretariat of Greenland), with supplementary names from Laursen (1972). Projection: WGS 84 UTM Zone 20N. Copyright © Geological Survey of Denmark and Greenland. References: Dawes, P.R. 1997: The Proterozoic Thule Supergroup, Greenland and Canada: history, lithostratigraphy and development. Geology of Greenland Survey Bulletin 174, 150 pp. https://doi.org/10.34194/ggub.v174.5025 Dawes, P.R. 2006: Explanatory notes to the Geological map of Greenland, 1:500 000, Thule, Sheet 5. Geological Survey of Denmark and Greenland Map Series 2, 97 pp. + map sheet. https://doi.org/10.34194/geusm.v2.4614 Laursen, D. 1972: The place names of North Greenland. Meddelelser om Grønland 180(2), 443 pp. + 18 plates. Morlighem, M. et al. 2017: BedMachine v3 [Surface; Thickness]: Complete bed topography and ocean bathymetry mapping of Greenlandfrom multibeam echo sounding combined with mass conservation. Geophysical Research Letters 44, 11051–11061. https://doi.org/10.1002/2017GL074954 Morlighem, M. et al. 2022: IceBridge BedMachine Greenland, Version 5 [Bed]. NASA National Snow and Ice Data Center Distributed Active Archive Center. https://doi.org/10.5067/GMEVBWFLWA7X (accessed January 2024). Svennevig, K. 2019: Preliminary landslide mapping in Greenland. Geological Survey of Denmark and Greenland Bulletin 43,e2019430207. https://doi.org/10.34194/GEUSB-201943-02-07 Thomassen, B., Krebs, J.D. & Dawes, P.R. 2002: Qaanaaq 2001: mineral exploration in the Olrik Fjord – Kap Alexander region, North-West Greenland. Danmarks og Grønlands Geologiske Undersøgelse Rapport 2002/86, 72 pp. + map. https://doi.org/10.22008/gpub/18491

This dataset provides spatially and temporally standardized freshwater fluxes from ice shelves around Antarctica, as well as ice-shelf integrated estimates. It is based on state-of-the-art and open-source datasets (Paolo et al., 2023; Greene et al., 2022; Mouginot et al., 2017; Morlighem et al., 2019) and contains the following data files:
1- iceshelf_calving_fluxes.gpkg
2- Merged_Integrated_melt_rates.csv
3- Merged_Integrated_melt_err_rates.csv
4- calving_bmachine_grid_v1.nc
5- bmelt_bmachine_grid_v1.nc

You can find below a brief description of this dataset (more information on the calculation can be found in the README file).

1) "iceshelf_calving_fluxes.gpkg" is a geopackage file that can be read inside QGIS. It contains the delimitation of ice shelves, based on the grounding line, ice front delineation, and naming convention from Mouginot et al, 2017. The dataset contains the following columns:
- fid: ice shelf id
- ice_shelf_name : ice_shelf_name based on the naming convention from Mouginot et al., 2017
- latitude : latitude of the ice shelf
- longitude : longitude of the ice shelf
- mass_change_YY : ice shelf calving rate in Gt/yr.
- mass_change_YY_err : error on ice shelf calving rate in Gt/yr.

2) "Merged_Integrated_melt_rates.csv" contains the following variable
- Column 1: ice shelf names based on the same convention as calving (see previous paragraph)
- Column 2-26: integrated basal melting rates in Gt/yr water equivalent, for years 1992 and 1994-2017 based on the dataset of Paolo et al., 2023.

3) "Merged_Integrated_melt_err_rates.csv" contains the following variable
- Column 1: ice shelf names based on the same convention as calving (see previous paragraph)
- Column 2-26: integrated error on basal melting rates in Gt/yr water equivalent, for years 1992 and 1994-2017, based on the dataset of Paolo et al., 2023.

4) "calving_bmachine_grid_v1.nc" is a netCDF that contains spatially distributed maps of calving rates in Gt/yr and related errors (Greene et al., 2022) along with ice shelf thicknesses (Paolo et al., 2023) for overlapping years, based on the flux calculation at the ice shelf front (using the mask from "iceshelf_calving_fluxes.gpkg"). The projection is polar stereographic (EPSG:3031), and the pixel size is 500 m. The extent of the layers is the same as BedMachine v3.

5) "bmelt_bmachine_grid_v1.nc" is a netCDF that contains spatially distributed maps of yearly basal melting rates in meters/year and related errors, based on the work of Paolo et al., 2023. The maps of basal melting have also been reprojected into the BedMachine grid (same as calving rates), which is in polar stereographic projection (EPSG:3031) with a pixel size of 500 m.

References
Mouginot, J., B. Scheuchl, and E. Rignot. (2017). MEaSUREs Antarctic Boundaries for IPY 2007-2009 from Satellite Radar, Version 2 [Data Set]. Boulder, Colorado USA. NASA National Snow and Ice Data Center Distributed Active Archive Center. https://doi.org/10.5067/AXE4121732AD. Date Accessed 07-25-2023.

Greene, C. A., Gardner, A. S., Schlegel, N.-J., & Fraser, A. D. (2022). Antarctic calving loss rivals ice-shelf thinning. Nature, 609(7929), 948–953. https://doi.org/10.1038/s41586-022-05037-w

Paolo, F. S., Gardner, A. S., Greene, C. A., Nilsson, J., Schodlok, M. P., Schlegel, N.-J., and Fricker, H. A.: Widespread slowdown in thinning rates of West Antarctic ice shelves, The Cryosphere, 17, 3409–3433, https://doi.org/10.5194/tc-17-3409-2023, 2023.

Morlighem, M., Rignot, E., Binder, T., Blankenship, D., Drews, R., Eagles, G., et al. (2019). Deep glacial troughs and stabilizing ridges unveiled beneath the margins of the Antarctic ice sheet. Nature Geoscience, 1–6. https://doi.org/10.1038/s41561-019-0510-8