NSF COLDEX Basal Unit maps derived from delay Doppler proccessing

<div>
<p>The geotiff files in this dataset are maps of the transect based data included as *.gmt files with the delay Doppler profiles in <a href="https://dataverse.tdl.org/previewurl.xhtml?token=a04c95b4-3d81-404b-a7fa-142f977ef0cd">“NSF COLDEX Delay Doppler Radar Profiles of Southern Dome A, Antarctica”</a>. <a href="https://docs.generic-mapping-tools.org/6.2/index.html">. Ice thicknesses from the [NSF COLDEX compilation](https://doi.org/10.18738/T8/M77ANK) were used for reference, and a two-way speed of light in ice used was 84.5 m/microsecond. GMT 6.2</a> was used to generate these files with the following steps:</p>

<ol>
<li>gmt blockmedian with a cell size of 5000 meters</li>
<li>gmt surface with a cell size of 1000 meters and a tension factor of 0.35</li>
<li>gmt grdmask with a search radius of 10000 meters</li>
</ol>

<p>The files include:</p>
<ul>
<li>srf.xyz_val.tiff: time delay to the surface [microseconds]</li>
<li>basal_depth.xyz_val.tiff: thickness to the base of the specular englacial unit [m]</li>
<li>basal_thk.xyz_val.tiff: thickness of the basal unit [m]</li>
<li>dsz_delay.xyz_val.tiff: time delay to 1 microsecond into scattering basal unit [microseconds]</li>
<li>dsz_power: signal to noise ratio of the echos in the basal unit [dB]</li>
<li>gradient.xyz_val.tiff: slope of the transition at the base of the specular englacial unit [dB/microsec]</li>
</ul>

<p> Files are in the Antarctic Polar Stereographic projection (ESPG 3031) with X and Y units of meters. </p>

<p>Browse PNG files are also included.</p>

<p>The following transects were excluded due to electromagnetic interference issues:</p>
<ul>
<li>CLX/MKB2m/X48a</li>
<li>CLX/MKB2m/X53a</li>
<li>CLX/MKB2n/R40a</li>
<li>CLX/MKB2n/R48a</li>
<li>CLX/MKB2n/R52a</li>
<li>CLX/MKB2n/R54a</li>
<li>CLX/MKB2n/R54b</li>
<li>CLX/MKB2n/R68a</li>
<li>CLX/MKB2n/R70a</li>
<li>CLX/MKB2n/R72a</li>
<li>CLX/MKB2n/X33a</li>
<li>CLX/MKB2n/X38a</li>
<li>CLX/MKB2n/X43a</li>
<li>CLX/MKB2n/X53b</li>
<li>CLX/MKB2n/X58a</li>
<li>CLX/MKB2n/X63a</li>
<li>CLX/MKB2o/R77a</li>
<li>NPXE/MKB2o/R55a</li>
</ul>
</div>