DOI: 10.5285/72f46ad0-063d-49a7-ba89-45edc5d9aac7
title: Subglacial lakes and hydrology across the Ellsworth Subglacial Highlands, West Antarctica, 1977-2017

description: 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Model (DEM) from Ellsworth Subglacial Highlands (ESH) was created from previously gridded bed elevation data and new unpublished radar data.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.
description: We used four existing gridded bed elevation data to create a new Digital Elevation Model (DEM) of the Ellsworth Subglacial Highlands (ESH). This data include: BedMap2 (Fretwell et al., 2013), ice thickness measurements from DELORES (2007-2009) and CECs (2005/2006) (Siegert et al., 2012), new along-track ice thickness measurements from the 2014 CECs RES campaign (Rivera et al., 2015) and unpublished radar measurements from the CECs 2017 RES field campaign in ESH region using a Very High Frequency (VHF) radar and a Medium Frequency (MF) radar (Zamora et al., 2019; Uribe et al., 2019). We used a 2 km grid mesh with a continuous curvature tension spline algorithm (Paxman et al., 2017) to grid the data. We masked the grid to remove interpolated values more than 5 km from the nearest measured data point and replaced them with BedMap2 bed elevation values. We down-sampled the original cell size of BedMap2 (1 km) to match the resolution of the new DEM (2 km) using the nearest neighbour algorithm. Values of bed elevation were calculated relative to the WGS84 ellipsoid using WGS84 EPSG3031 as spatial reference system. Additionally, we down-sampled de cell size of the ice surface data from CryoSat2 (Slater et al., 2018) to match the resolution of the new DEM (2 km) and we built a hydropotential model to determine the hydrological head, following Shreve (1972). Using this hydropotential model we simulated the subglacial drainage system of the ESH following Schwanghart and Scherler (2014). More details of the processing and modelling is provided in Napoleoni et al. (submitted).
description: Matlab R2020b Reflex-Win v. 8.0.2 QGIS 3.2.1
description: In January 2014 ~1100 km of RES data collected by CECs over an area of ~7000 km2 were acquired with a line spacing of ~8 km. The CECs survey during December of the same year was collected over a nested grid around SLC and along the host subglacial trough further north towards RIS, surveying a total of ~1050 km. During December 2017 the CECs radar survey acquired a total of ~700 km of RES data along the same trough. We assume the same uncertainties as Bedmap2 for the region beyond Ellsworth Subglacial Highland.