NSF COLDEX CXA1 laser ranging, magnetic field strength and orientation, and positioning 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.
DATASET ORGANIZATION Transects were collected in preplanned systems with the following parameters:
- 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.
- 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.
- 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.
- SAD corridor (SAD/MKB##/X###|Y####) designed to characterize the Saddle region near South Pole approximately perpendicular to the flow lines, rooted from the EPSG:3031 polar stereographic projection at -73.8 degrees and separated by 2.5 km in its Y direction and 2.5 km in the its X direction.
- Untargeted transit lines used the name of the expedition (CXA1) as the project, and used the flight and the increment within the flight to name the Transect (eg (CXA1/MKB2n/F10T02a).
POSITIONING GPS provides the positioning (and timing) for all other data streams:
- IPUTG1B (ICECAP Positioning/UTIG GPS Level 1B): real time CA-code 1 Hz GPS position data
MAGNETICS Magnetic data provides constraints on the depth to crystalline rock, the temperature structure of the crust, and the underlying tectonics
- IMGEO1B (ICECAP Magnetics: Geometrics Level 1B): georeferenced total magnetic field data; 10 Hz ASCII
- IMFGM1B (ICECAP Magnetics/Flux Gate Magnetometer Level 1B): georeferenced aircraft referenced magnetic field vectors; 10 Hz ASCII
ALTIMETRY Laser altimetry provides for surface shape and altimetry validation. See
COLDEX 2022-23 Riegl Laser Altimeter Level 2 Geolocated Surface Elevation Triplets for derived surface elevation data.
- ILUTP1B (ICECAP Lidar/UTIG Profiler Level 1B): georeferenced laser range data, no orientation corrections; 3.5 Hz ASCII
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.
