A new bed elevation model for the Weddell Sea sector of the West Antarctic Ice Sheet

Abstract

We present a new digital elevation model (DEM) of the bed, with a 1 km gridding, of the Weddell Sea (WS) sector of the West Antarctic Ice Sheet (WAIS). The DEM has a total area of ∼ 125 000 km 2 covering the Institute, Möller and Foundation ice streams, as well as the Bungenstock ice rise. In comparison with the Bedmap2 product, our DEM includes new aerogeophysical datasets acquired by the Center for Remote Sensing of Ice Sheets (CReSIS) through the NASA Operation IceBridge (OIB) program in 2012, 2014 and 2016. We also improve bed elevation information from the single largest existing dataset in the region, collected by the British Antarctic Survey (BAS) Polarimetric radar Airborne Science Instrument (PASIN) in 2010-2011, from the relatively crude measurements determined in the field for quality control purposes used in Bedmap2. While the gross form of the new DEM is similar to Bedmap2, there are some notable differences. For example, the position and size of a deep subglacial trough (∼ 2 km below sea level) between the ice-sheet interior and the grounding line of the Foundation Ice Stream have been redefined. From the revised DEM, we are able to better derive the expected routing of basal water and, by comparison with that calculated using Bedmap2, we are able to assess regions where hydraulic flow is sensitive to change. Given the potential vulnerability of this sector to ocean-induced melting at the grounding line, especially in light of the improved definition of the Foundation Ice Stream trough, our revised DEM will be of value to ice-sheet modelling in efforts to quantify future glaciological changes in the region and, from this, the potential impact on global sea level. The new 1 km bed elevation product of the WS sector can be found at https://doi.org/10.5281/zenodo.1035488.Published by Copernicus Publications. 712 H. Jeofry et al.: A new bed elevation model for the Weddell Sea sector

Radar‐Detected Englacial Debris in the West Antarctic Ice Sheet

“…The British Antarctic Survey Polarimetric‐radar Airborne Science Instrument ice‐sounding radar system (Jeofry et al, ) was used to collect RES data in and around Horseshoe Valley in the austral summer of 2010/2011 for the British Antarctic Survey Institute Möller Antarctic Funding Initiative survey (https://doi:10.5285/8a975b9e‐f18c‐4c51‐9bdb‐b00b82da52b8). PASIN operates at a frequency of 150 MHz, using a pulse‐coded waveform acquisition rate of 312.5 Hz and bandwidth of 12 MHz.…”

“…An electromagnetic wave propagation speed of 0.168 m/ns and a 10‐m firn correction was applied to all RES transects (Ross et al, ). Technical details of the Polarimetric‐radar Airborne Science Instrument system and additional details on the acquisition and processing of the Institute Möller Antarctic Funding Initiative RES data are available in Jeofry et al (), and references therein.…”

Subglacial Geology and Geomorphology of the Pensacola‐Pole Basin, East Antarctica

“…Antarctic ice thickness and bedrock elevation are determined using (predominantly airborne) RES surveys. In order to produce an updated ice thickness grid and bedrock digital elevation model (DEM) for the South Pole region, it was necessary to compile ice thickness measurements from a number of airborne geophysical campaigns, including PolarGAP Winter et al, 2018), FISS, RECISL (Humbert et al, 2018), ICEGRAV Paxman et al, 2017), IMAFI (Jeofry et al, 2018;Ross et al, 2012), ICECAP (Blankenship et al, 2017), AGAP , Operation IceBridge (Leuschen et al, 2016), AFI-Coats Land , PPT (Studinger et al, 2006), DUFEK (Ferris et al, 2003), CASERTZ (Bell et al, 1998), and SPRI-NSF-TUD (Drewry, 1983). Detailed information on the acquisition and processing of the RES data from each survey can be found in the respective references listed above.…”

Major Ice Sheet Change in the Weddell Sea Sector of West Antarctica Over the Last 5,000 Years

“…Here, by reviewing the available information, we establish how each of the glacial histories are supported with data and models, where evidence is contradictory, and what new data might be needed to reach a single consistent glacial history for the region. This is important, because the SWSE could be at a physical threshold of major change, with two ice streams sitting atop a major reversing bed slope, and several ice streams grounded far (~2 km) below sea level (Jeofry, Ross, Corr et al, ; Ross et al, ). This makes them potentially unstable to perturbations in grounding line position (Wright et al, ).…”