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1. COLDEX Unfocused Airborne VHF Radar Transects 2022-2023 South Pole Field Season

   https://doi.org/10.18738/T8/XPMLCC  

   Young, Duncan; Greenbaum, Jamin S; Kerr, Megan E; Singh, Shivangini; Chan, Kristian; Buhl, Dillon P; Ng, Gregory C; Kempf, Scott D; Echeverry, Gonzalo; Blankenship, Donald D (January 2024, Texas Data Repository)

   These transect organized radargrams were collected as part of the Center for Oldest Ice Exploration (COLDEX) Science and Technology Center (https://www.coldex.org) in the 2022/23 (CXA1) airborne reconnaissance field season. The raw 3 TB data is deposited at the USAP data center at https://doi.org/10.15784/601768. Flight organized data with additional processing by the University of Kansas to remove electromagnetic interference can be found at the Open Polar Radar server (https://www.openpolarradar.org). The science goal was to characterize the ice sheet between Antarctica's Dome A and Amundsen Scott South Pole Station, to locate sites of interest for the drilling of an ice core with ages spanning the mid-Pleistocene. The radar was deployed on Balser C-FMKB, and flown at ranges of up to 800 km from South Pole Station at velocities of 90 m/s and typical altitude above ground of 600 m. Other instruments included a UHF array system provided by the University of Kansas, a gravity meter, a magnetometer, a laser altimeter, and multiple global navigation satellite systems receivers. The radar data is used for finding ice thickness, bed character, englacial structure and surface assessment. Dataset organization Transects are provided a P/S/T nomenclature, organized by the Project they are flying in, the acquisition System (typically named after the aircraft) and the Transect within the Project. 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). Processing These data represent range compressed VHF radargrams as collected and analyzed in the field. The data are from the MARFA radar system, a 60 MHz ice penetrating radar system that has operated in several different guises over the years. MARFA operates with a 1 microsecond chirp with a design bandwidth of 15 MHz, allowing for ~8 range resolution. The record rate after onboard stacking is 200 Hz. High and low gain channels are collected from antennas on each side of the aircraft. In ground processing, the data were stacked 10x coherently to reduce range delayed incoherent surface scattering, and then stacked 5 times incoherently to improve image quality. In this preliminary processing, the effective resolution of deep scattering is several hundred meters due to range ambiguities at depth. Data format These data collection represents georeferenced, time registered instrument measurements (L1B data) converted to SI units. The data format are netCDF3 files, following the formats used for NASA/AAD/UTIG's ICECAP/OIB project at NASA's NSIDC DAAC (10.5067/0I7PFBVQOGO5). Metadata fields can be accessed using the open source ncdump tool, or c, python or matlab modules. A Keyhole Metadata Language (KML) file with geolocation for all transects is also provided. See https://www.loc.gov/preservation/digital/formats/fdd/fdd000330.shtml for resources on NetCDF-3, and https://nsidc.org/data/IR2HI1B/versions/1 for a description of the similar OIB dataset. Acknowledgements This work was supported by the Center for Oldest Ice Exploration, an NSF Science and Technology Center (NSF 2019719). We thank the NSF Office of Polar Programs, the NSF Office of Integrative Activities, and Oregon State University for financial and infrastructure support, and the NSF Antarctic Infrastructure and Logistics Program, and the Antarctic Support Contractor for logistical support. Additional support was provided by the G. Unger Vetlesen Foundation. 

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2. COLDEX Unfocused Airborne VHF Radar Transects: 2023-2024 South Pole Field Season

   https://doi.org/10.18738/T8/FV6VNT  

   Young, Duncan; Singh, Shivangini; Kerr, Megan E; Ng, Gregory; Buhl, Dillon P; Blankenship, Donald D; Young, Duncan (January 2024, Texas Data Repository)

   These transect organized radargrams were collected as part of the Center for Oldest Ice Exploration (COLDEX) Science and Technology Center (https://www.coldex.org) in the 2023/24 (CXA2) airborne reconnaissance field season. The raw 3 TB data is deposited at the USAP data center at https://doi.org/10.15784/601768. Flight organized data with additional processing by the University of Kansas to remove electromagnetic interference can be found at the Open Polar Radar server (https://www.openpolarradar.org). The science goal was to characterize the ice sheet between Antarctica's Dome A and Amundsen Scott South Pole Station, to locate sites of interest for the drilling of an ice core with ages spanning the mid-Pleistocene. The radar was deployed on Balser C-FMKB, and flown at ranges of up to 800 km from South Pole Station at velocities of 90 m/s and typical altitude above ground of 600 m. Other instruments included a UHF array system provided by the University of Kansas, a gravity meter, a magnetometer, a laser altimeter, and multiple global navigation satellite systems receivers. The radar data is used for finding ice thickness, bed character, englacial structure and surface assessment. Dataset organization Transects are provided a P/S/T nomenclature, organized by the Project they are flying in, the acquisition System (typically named after the aircraft) and the Transect within the Project. 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 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 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). Processing These data represent range compressed VHF radargrams as collected and analyzed in the field. The data are from the MARFA radar system, a 60 MHz ice penetrating radar system that has operated in several different guises over the years. MARFA operates with a 1 microsecond chirp with a design bandwidth of 15 MHz, allowing for ~8 meter range resolution. The record rate after onboard stacking is 200 Hz. High and low gain channels are collected from antennas on each side of the aircraft. In ground processing, the data were stacked 10x coherently to reduce range delayed incoherent surface scattering, and then stacked 5 times incoherently to improve image quality. In this preliminary processing, the effective resolution of deep scattering is several hundred meters due to range ambiguities at depth. Data format These data collection represents georeferenced, time registered instrument measurements (L1B data) converted to SI units. The data format are netCDF3 files, following the formats used for NASA/AAD/UTIG's ICECAP/OIB project at NASA's NSIDC DAAC (10.5067/0I7PFBVQOGO5). Metadata fields can be accessed using the open source ncdump tool, or c, python or matlab modules. A Keyhole Metadata Language (KML) file with geolocation for all transects is also provided. See https://www.loc.gov/preservation/digital/formats/fdd/fdd000330.shtml for resources on NetCDF-3, and https://nsidc.org/data/IR2HI1B/versions/1 for a description of the similar OIB dataset. Acknowledgements This work was supported by the Center for Oldest Ice Exploration, an NSF Science and Technology Center (NSF 2019719). We thank the NSF Office of Polar Programs, the NSF Office of Integrative Activities, and Oregon State University for financial and infrastructure support, and the NSF Antarctic Infrastructure and Logistics Program, and the Antarctic Support Contractor for logistical support. Additional support was provided by the G. Unger Vetlesen Foundation. 

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3. SOAR PPT (Pensacola-Pole Transect) gridded aerogeophysical observations

   https://doi.org/10.18738/t8/smlowr  

   Blankenship, Donald; Holt, John; Kempf, Scott; Morse, David; Davis, Marcy; Bell, Robin; Arko, Robert; Young, Duncan A; Kempf, Scott D (January 2025, Texas Data Repository)

   {"Abstract":["The PPT survey extended from the Ross Ice Shelf, southward over the TAM along 150W between the Scott and Reedy Glaciers, and through the South Pole. Approximately 15,000 line km were flown. North-south oriented transects were flown 10 km apart and west-east tie lines were flown with a 30 km line spacing. Fifteen km long transect 'run-ins' and 'run-outs' were added to each line, thus ensuring data collection to survey boundaries. Laser altimetry, ice-penetrating radar, gravity and magnetic field intensity data were collected. This work was funded by NSF-OPP grant 9615832 with the project title: Collaborative Research: Contrasting Architecture and Dynamics of the Transantarctic Mountains (Pensacola-Pole Transect). Principal Investigators were D.D. Blankenship, University of Texas Institute for Geophysics, and R.E. Bell and W.R. Buck, Lamont-Doherty Earth Observatory.\n<br>\n<br>\nThis work was conducted by the Support Office for Aerogeophysical Research (SOAR) NSF facility under cooperative agreement OPP-9319379. The 1998/1999 field season <a href="http://hdl.handle.net/2152/65412"> report </a>(Holt et al 1999) describes the field work in more detail.\n<br>\n<br>\nThese data are gridded orthogonal data with a point every 850 m. Data is in a space delimited ASCII table with three columns: Longitude, Latitude and geophysical observation. Grids are smoothed using a Gaussian filter (2.125 km for gravity, magnetic field anomaly, surface elevation and 8.5 km for ice thickness) and surfaced using a bicubic spline method.\n<br>\nObservations include:\n<ol>\n<li> Bed elevation (m, WGS-84) </li> \n<li> Gravity disturbance (mGal, WGS-84) </li> \n<li> Ice Thickness (m) </li> \n<li> Laser Derived Surface Elevation (m, WGS-84) </li> \n<li> Magnetic Anomaly (nT, IGRF) </li> \n<li> Radar Derived Surface Elevation (m, WGS-84) </li> \n</ol>\nA browse image is included. \n<br><br>\n<i>Acknowledgement: </i><br>\nIn keeping with NSF Grant Policy, any publication using these data (including web documents) must contain the following acknowledgment: "This material is based on work supported by the National Science Foundation under cooperative agreement OPP-9319379." Also, any oral presentation utilizing these materials should acknowledge the support of the National Science Foundation. In addition, we request that any oral presentation, web page or publication also acknowledge SOAR and the University of Texas. A suitable citation for PPT data is:\n<br>\n<i>Davis, M.B., 2001, Subglacial Morphology and Structural Geology in the Southern Transantarctic Mountains from Airborne Geophysics, M.S. Thesis, Univ. of Texas, 133 pp.<a href="http://dx.doi.org/10.26153/tsw/2786">doi:10.26153/tsw/2786</a></i>\n<br>\nThese data represent the data that was hosted on the UTIG webpage at https://www-udc.ig.utexas.edu/external/facilities/aero/data/soar/PPT/SOAR_ppt.htm."]} 

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4. NSF COLDEX 2023-24 Riegl Laser Altimeter Level 2 Geolocated Surface Elevation Triplets:AlternativeTitle

   https://doi.org/10.18738/T8/PNBFOL  

   Young, Duncan; Ng, Gregory; Kerr, Megan E; Singh, Shivangini; Buhl, Dillon; Echeverry, Gonzalo; Richter, Thomas G; Kempf, Scott D; Blankenship, Donald D; Young, Duncan (January 2024, Texas Data Repository)

   These laser altimetry data were collected as part of the 2023-24 <a href="https://www.coldex.org">NSF COLDEX </a> CXA2 airborne campaign targeting the southern flank of East Antarctica's Dome A. In this Level 2 product, we have used the laser range to the surface and complementary aircraft position data to calculated the ice surface elevation, which is an important constraint on ice flow. Complementary radar, gravity, magnetics and imagery were also collected. <p> <i>Data format:</i>Data are formatted as text files with a header and the following tab delimited format columns. Data are in the same format as similar <a href="https://doi.org/10.5067/JV9DENETK13E"> IceBridge ILUTP2 altimetry data. </a> <p> Field 1: Year (UTC)<br> Field 2: Day of year (UTC)<br> Field 3: Second of day (UTC)<br> Field 4: Longitude Angle (deg) (WGS-84) <br> Field 5: Latitude Angle (deg) (WGS-84)<br> Field 6: Laser Derived Surface Elevation (m) (WGS-84)<br> <p> Missing values have been replaced by "nan". The effective footprint of the laser data is 25 m along track by 1 meter across track. Some cloud filtering was performed. <p> <i>Uncertainties</i>: A comparison of this laser altimetry dataset north of 87.5˚S with the <a href="https://doi.org/10.7910/DVN/EBW8UC"> REMAv2 </a>100 m mosaic digital terrain model indicate a median bias of 17 cm and a root mean squared (RMS) difference of 20 cm. Intersections between profiles within this survey, on the Antarctic Plateau but away from South Pole Station, have RMS differences of 6.8 cm. <p> <i>Datum: </i>WGS-84 ellipsoid; ITRF 2008 <p> <i>Geolocation: </i>Positioning and orientation for CXA1 came from loosely coupled joint PPP/inertial solutions using a Novatel OEM-4 GPS receiver and an iMAR FSAS IMU. <p> <i>Pointing bias: </i> roll: 0.340 degrees; pitch: -0.505 degrees <br> Pointing angle (pointing bias) is the angular offset of the downward-pointing laser boresight respect to the vehicle body frame's vertical (Z) axis. This estimated angle is derived by comparing measurements at crossovers. Pointing angle is provided in the vehicle body frame, using the laser origin for the rotation node. A positive pitch rotation indicates that the laser beam intersects the ground forward of the z-axis. A positive roll rotation indicates that the laser beam intersects the ground left of the z-axis. Pointing biases were found using the minimization of cross over difference method from <a href="http://dx.doi.org/10.3189/2015JoG14J048">Young et al., 2015</a>. <p> <i>Level arm: </i>X: 0 m; Y: 0.2 m; Z: -0.22 m <br> The lever arm is the position of the laser origin relative to the aircraft position solution, estimated using crossover-error minimization. Lever arm is provided in the vehicle body frame, with +X is forward, +Y is right, and +Z is down. Lever arm was measured after installation in the field. <p> <i>GNSS_antenna: </i>AeroAntenna AT1675-17W-TCNF-000-RG-36-NM <br> The coordinate system for the laser-gps lever arm is X forward, Y right, and Z down, from the center of position. 

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5. NSF COLDEX 2022-23 Riegl Laser Altimeter Level 2 Geolocated Surface Elevation Triplets

   https://doi.org/10.18738/T8/99IEOG  

   Young, Duncan A; Greenbaum, Jamin S; Kerr, Megan E; Echeverry, Gonzalo; Chan, Kristian; Singh, Shivangini (January 2024, Texas Data Repository)

   These laser altimetry data were collected as part of the 2022-23 <a href="https://www.coldex.org">NSF COLDEX </a> CXA1 airborne campaign targeting the southern flank of East Antarctica's Dome A. In this Level 2 product, we have used the laser range to the surface and complementary aircraft position data to calculated the ice surface elevation, which is an important constraint on ice flow. Complementary radar, gravity, magnetics and imagery were also collected. <p> <i>Data format:</i>Data are formatted as text files with a header and the following tab delimited format columns. Data are in the same format as similar <a href="https://doi.org/10.5067/JV9DENETK13E"> IceBridge ILUTP2 altimetry data. </a> <p> Field 1: Year (UTC)<br> Field 2: Day of year (UTC)<br> Field 3: Second of day (UTC)<br> Field 4: Longitude Angle (deg) (WGS-84) <br> Field 5: Latitude Angle (deg) (WGS-84)<br> Field 6: Laser Derived Surface Elevation (m) (WGS-84)<br> <p> Missing values have been replaced by "nan". The effective footprint of the laser data is 25 m along track by 1 meter across track. Some cloud filtering was performed. <p> <i>Uncertainties</i>: A comparison of this laser altimetry dataset north of 87.5˚S with the <a href="https://doi.org/10.7910/DVN/EBW8UC"> REMAv2 </a>100 m mosaic digital terrain model indicate a median bias of 17 cm and a root mean squared (RMS) difference of 20 cm. Intersections between profiles within this survey, on the Antarctic Plateau but away from South Pole Station, have RMS differences of 6.4 cm. <p> <i>Datum: </i>WGS-84 ellipsoid; ITRF 2008 <p> <i>Geolocation: </i>Positioning and orientation for CXA1 came from loosely coupled joint PPP/inertial solutions using a Novatel OEM-4 GPS receiver and an iMAR FSAS IMU. <p> <i>Pointing bias: </i> roll: -0.2 degrees; pitch: -0.350 degrees <br> Pointing angle (pointing bias) is the angular offset of the downward-pointing laser boresight respect to the vehicle body frame's vertical (Z) axis. This estimated angle is derived by comparing measurements at crossovers. Pointing angle is provided in the vehicle body frame, using the laser origin for the rotation node. A positive pitch rotation indicates that the laser beam intersects the ground forward of the z-axis. A positive roll rotation indicates that the laser beam intersects the ground left of the z-axis. Pointing biases were found using the minimization of cross over difference method from <a href="http://dx.doi.org/10.3189/2015JoG14J048">Young et al., 2015</a>. <p> <i>Level arm: </i>X: 0 m; Y: 0.2 m; Z: -0.22 m <br> The lever arm is the position of the laser origin relative to the aircraft position solution, estimated using crossover-error minimization. Lever arm is provided in the vehicle body frame, with +X is forward, +Y is right, and +Z is down. Lever arm was measured after installation in the field. <p> <i>GNSS_antenna: </i>AeroAntenna AT1675-17W-TCNF-000-RG-36-NM <br> The coordinate system for the laser-gps lever arm is X forward, Y right, and Z down, from the center of position. 

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