NSF COLDEX Ice Penetrating Radar Derived Grids of the Southern Flank of Dome A

<p>NSF COLDEX performed two airborne campaigns from South Pole Station over the Southern Flank of Dome A and 2022-23 and 2023-24, searching for a potential site of a continuous ice core that could sample the mid-Pleistocene transition. Ice thickness data extracted from the MARFA radar system has allow for a new understanding of this region.</p>

<p>Here we generate crustal scale maps of ice thickness, bed elevation, specularity content, subglacial RMS deviation, surface elevation and fractional basal ice thickness with 1 km sampling, and 10 km resolution. We include both masked and unmasked grids.</p>

<p> The projection is in the SCAR standard ESPG:3031 polar stereographic projection with true scale at 71˚S.</p>

<p>These geotiffs were generated using performed using GMT6.5 (<a href="https://doi.org/10.1029/2019GC008515">Wessel et al., 2019</a>) using the pygmt interface, by binning the raw data to 2.5 km cells, and using the <a href="https://github.com/sakov/nn-c"> nnbathy </a> program to apply natural neighbor interpolation to 1 km sampling. A 10 km Gaussian filter - representing typical lines spacings - was applied and then a mask was applied for all locations where the nearest data point was further than 8 km. </p>

Ice thickness, bed elevation and RMS deviation @ 400 m length scale (<a href="http://dx.doi.org/10.1029/2000JE001429">roughness</a>) data includes the following datasets:
<ul>
<li> UTIG/CRESIS <a href="https://doi.org/10.18738/T8/J38CO5">NSF COLDEX Airborne MARFA data</a></li>
<li> British Antarctic Survey <a href="https://doi.org/10.5285/0f6f5a45-d8af-4511-a264-b0b35ee34af6">AGAP-North</a></li>
<li> LDEO <a href="https://doi.org/10.1594/IEDA/317765"> AGAP-South </a></li>
<li> British Antarctic Survey <a href="https://doi.org/10.5270/esa-8ffoo3e">Polargap</a></li>
<li> UTIG Support Office for Airborne Research <a href="https://doi.org/10.15784/601588">Pensacola-Pole Transect (PPT) </a></li>
<li> NASA/CReSIS <a href="https://doi.org/10.5067/GDQ0CUCVTE2Q"> 2016 and 2018 Operation Ice Bridge </a> </li>
<li> ICECAP/PRIC <a href="https://doi.org/10.15784/601437"> SPICECAP Titan Dome Survey </a>
</ul>

<p>Specularity content (<a href="https://doi.org/10.1109/LGRS.2014.2337878">Schroeder et al. 2014</a>) is compiled from <a href="https://doi.org/10.18738/T8/KHUT1U"> Young et al. 2025a </a> and <a href="https://doi.org/10.18738/T8/6T5JS6"> Young et al. 2025b</a>.</p>

<p>Basal ice fractional thickness is complied from manual interpretation by Vega González, Yan and Singh. </p>

<p> Surface elevations is derived by combining the following datasets:
<ul>
<li> UTIG <a href="https://doi.org/10.18738/T8/99IEOG"> 2022-23 </a> and <a href="https://doi.org/10.18738/T8/PNBFOL"> 2023-24 </a> NSF COLDEX laser altimetry data </li>
<li> BAS <a href="https://doi.org/10.5285/d55e87dd-a74d-4182-be99-93ab805103ab"> 2015-16 </a> Polargap laser altimetry data (used for the surface in the bed elevation pick data)</li>
<li> SOAR <a href="https://doi.org/10.18738/T8/QMEWFA"> 1998-99 </a> Pensacola-Pole Transect laser altimetry data </li>
<li> ICECAP <a href="https://doi.org/10.15784/601437"> 2016-17 </a> SPICECAP laser altimetry data </li>
<li> NASA <a href="https://doi.org/10.5067/ATLAS/ATL14.004"> 2019-2024 </a> ICESat-2/ATLAS gridded surface elevation data (north of 88˚S)</li>
</ul>

<p>Code to generated these grids can be found at <a href="https://github.com/smudog/COLDEX_dichotomy_paper_2025"> at github.com </a></p>