DOI: 10.18738/t8/lhsvh5
title: NSF COLDEX 2023-2024 Airborne Season (CXA2): Level 1B Serial Instrument Measurements

description: &lt;b&gt;NSF COLDEX CXA2 laser ranging, magnetic field strength and orientation, and positioning&lt;/b&gt;&lt;br&gt;
&lt;br&gt;
This data collection represents georeferenced, time registered instrument measurements (Level 1B data) converted to SI units, and is of most interest to users who wish to reprocess the data. Users interested in geophysical observables (eg magnetic anomalies and surface elevation) should used the derived Level 2 datasets. The data format are space delimited ASCII files, following the formats used for UTIG predecessor ICECAP/OIB project at NASA's NSIDC DAAC. Fields are described in the # delimited detailed header for each granule.&lt;br&gt;
&lt;br&gt;
&lt;b&gt;DATASET ORGANIZATION&lt;/b&gt;&lt;br&gt;
Transects were collected in preplanned systems with the following parameters:
&lt;ul&gt;
&lt;li&gt;CLX radials (CLX/MKB##/R###), attempting to emulate flow lines from Dome A and radiating (in the EPSG:3031 polar stereographic projection) from easting 965 km northing 385 km, with a separation of 0.25 degrees.&lt;/li&gt;
&lt;li&gt;CLX corridor (CLX/MKB##/X###) rotated from the EPSG:3031 polar stereographic projection at -150 degrees and separated by 10 km in the Y direction and 3.75 km in the X direction&lt;/li&gt;
&lt;li&gt;CLX2 corridor (CLX2/MKB##/X###) rotated from the EPSG:3031 polar stereographic projection at -150 degrees and separated by 2.5 km in its Y direction and 2.5 km in its X direction&lt;/li&gt;
&lt;li&gt;NPXE radials (NPXE/MKB##/R####) primarily designed to survey the Upper Byrd Glacier Catchment, constitute spokes radiating from South Pole separated by 2 degrees, in the EPSG:3031 polar stereographic projection &lt;/li&gt;
&lt;li&gt;Untargeted transit lines used the name of the expedition (CXA2) as the project, and used the flight and the increment within the flight to name the Transect (eg (CXA2/MKB2n/F10T02a).&lt;/li&gt;
&lt;/ul&gt;

&lt;br&gt;
&lt;b&gt;POSITIONING&lt;/b&gt;&lt;br&gt;
GPS provides the positioning (and timing) for all other data streams:&lt;br&gt;
&lt;ul&gt;
&lt;li&gt;IPUTG1B (ICECAP Positioning/UTIG GPS Level 1B): real time CA-code 1 Hz GPS position data&lt;/li&gt;
&lt;/ul&gt;
&lt;br&gt;
&lt;b&gt;MAGNETICS&lt;/b&gt;&lt;br&gt;
Magnetic data provides constraints on the depth to crystalline rock, the temperature structure of the crust, and the underlying tectonics&lt;br&gt;
&lt;ul&gt;
&lt;li&gt;IMGEO1B (ICECAP Magnetics: Geometrics Level 1B): georeferenced total magnetic field data; 10 Hz ASCII&lt;/li&gt;
&lt;li&gt;IMFGM1B (ICECAP Magnetics/Flux Gate Magnetometer Level 1B): georeferenced aircraft referenced magnetic field vectors; 10 Hz ASCII&lt;/li&gt;
&lt;/ul&gt;
&lt;br&gt;
&lt;b&gt;ALTIMETRY&lt;/b&gt;&lt;br&gt;
Laser altimetry provides for surface shape and altimetry validation. See &lt;a NSF href="https://doi.org/10.18738/T8/PNBFOL"&gt; COLDEX 2023-24 Riegl Laser Altimeter Level 2 Geolocated Surface Elevation Triplets&lt;/a&gt; for derived surface elevation data.&lt;br&gt;
&lt;ul&gt;
&lt;li&gt;ILUTP1B (ICECAP Lidar/UTIG Profiler Level 1B): georeferenced laser range data, no orientation corrections; 3.5 Hz ASCII&lt;/li&gt;
&lt;/ul&gt;
&lt;br&gt;
This work was supported by the U.S. National Science Foundation Center for Oldest Ice Exploration (NSF COLDEX), an NSF Science and Technology Center (NSF 2019719). We thank the NSF Office of Polar Programs, the NSF Office of Integrative Activities and the NSF Antarctic Infrastructure and Logistics Program, Kenn Borek Airlines and the Antarctic Support Contractor for logistical support. Additional support came from the Open Polar Radar project (NSF grant 2127606) award to the University of Texas at Austin and a gift to UTIG from the G. Unger Vetlesen foundation.