USAP-DC

{"dp_type": "Dataset", "free_text": "Coldex"}

[{"awards": null, "bounds_geometry": null, "date_created": "Fri, 12 Dec 2025 00:00:00 GMT", "description": "The spatial variability of firn properties, including microstructure, is critical for mass-balance estimates and ice- core interpretations. This includes local and regional variations in firn microstructure, which influence compaction and air movement in the firn. Some of the oldest ice cores are located in blue-ice areas and originated from low-accumulation areas. Surface processes, including small variations in surface conditions and topography, may cause significant alteration of the firn microstructure and bulk firn properties in low-accumulation areas, as firn may interact with surface processes for long periods of time (e.g., hundreds of years). Here, we examine the impact of very low-accumulation rates (A = O(10\u22123 \u2212 10\u22122 m/a)) on firn microstructure using micro-computed tomography data from a firn core (PICO2303) retrieved in the accumulation zone at Allan Hills Blue Ice Area (BIA), Antarctica during the 2023-2024 NSF-COLDEX field season. First, we analyze microstructural parameters such as total porosity, density, specific surface area, degree of anisotropy, and structure thickness, as well as 2D and 3D reconstructed digital datasets. Subsequently, we compare our observations with a firn core from Dadic et al. (2015) that we refer to here as AHMIF, and located \u223c9 km downslope. In the PICO2303 core, we find 1) faceted grains, 2) wind crusts, 3) vertically oriented networks, and 4) specific surface area of 1.5 m^2/kg greater and density of 205 kg/m^3 lower below the surface compared to those measured in the AHMIF core. We propose that these characteristics are a result of differences in both surface processes (e.g., formation and decay of sastrugi) and subsurface evolution (e.g., depth-hoar formation) that likely occur at varying degrees.", "east": null, "geometry": null, "keywords": "Antarctica; Cryosphere", "locations": "Antarctica", "north": null, "nsf_funding_programs": null, "persons": "Horlings, B. Ilyse", "project_titles": null, "projects": null, "repositories": null, "science_programs": null, "south": null, "title": "Firn microstructure from micro-computer tomography of PICO2303, Allan Hills Blue Ice Area, Antarctica", "uid": "602002", "west": null}, {"awards": "2019719 Brook, Edward", "bounds_geometry": ["POLYGON((0 -84,12 -84,24 -84,36 -84,48 -84,60 -84,72 -84,84 -84,96 -84,108 -84,120 -84,120 -84.6,120 -85.2,120 -85.8,120 -86.4,120 -87,120 -87.6,120 -88.2,120 -88.8,120 -89.4,120 -90,108 -90,96 -90,84 -90,72 -90,60 -90,48 -90,36 -90,24 -90,12 -90,0 -90,0 -89.4,0 -88.8,0 -88.2,0 -87.6,0 -87,0 -86.4,0 -85.8,0 -85.2,0 -84.6,0 -84))"], "date_created": "Mon, 01 Dec 2025 00:00:00 GMT", "description": "These data comprise the RINEX formatted GNSS observations for flights in the 2023-2024 COLDEX field campaign, as well as the raw Novatel SPAN logs with rotation and acceleration information. The survey aircraft, Basler C-FMKB, had three GPS antennas (MKB2, MKB3, and MKB4) mounted on each wing and on the tail, and a single GNSS antenna (MKB1) mounted on roof near the center of gravity of the aircraft. Multiple receivers can be on each antenna. Data was recorded by a Javad Quattro-G3D (JVD) on all four antennas at 1 Hz, and on the wing antennas at 10 Hz, the Novatel SPAN OEM4 (NVT) on MKB1 at 1 Hz, and two Topcon NET-G3A (TG3) on the tail and one wing at 10 Hz. A 2 Hz Trimble Net R5 on the ground was operated for most flights (ZWD1 at Williams Field, or ZSP1 at South Pole), along with high rate Earthscope data from South Pole Station (AMU2).\r\n\u003cbr/\u003e\r\n\u003cbr/\u003eData is organized in a hierarchy with the following levels:\r\n\u003cbr/\u003e*Instrument type\r\n\u003cbr/\u003e*Flight\r\n\u003cbr/\u003e*Season\r\n\u003cbr/\u003e*Receiver (designated by antenna)\r\n\u003cbr/\u003e*Flight\r\n\u003cbr/\u003e*UTIG Stream name\r\n\u003cbr/\u003e\r\n\u003cbr/\u003eASCII RINEX data are generated by UNAVCO\u2019s teqc program and include:\r\n\u003cbr/\u003e*nav - GPS Nav Data\r\n\u003cbr/\u003e*rnv - GLONASS Nav Data\r\n\u003cbr/\u003e*obs - GPS Observation data\r\n\u003cbr/\u003e\r\n\u003cbr/\u003e_________________________________________________________________________\r\n\u003cbr/\u003e\r\n\u003cbr/\u003eSPAN data are binary files containing both the NVT GPS data that is reformatted as RINEX above, but also IMU messages. Formats for these OEM4 data can be found at Novatel\u2019s website: https://hexagondownloads.blob.core.windows.net/public/Novatel/assets/Documents/Manuals/om-20000047/om-20000047.pdf", "east": 120.0, "geometry": ["POINT(60 -87)"], "keywords": "Aerogeophysics; Allan Hills; Antarctica; Beardmore Glacier; Cryosphere; David Glacier; Dome A; GPS Data; South Pole; South Pole Basin", "locations": "Antarctica; Beardmore Glacier; David Glacier; South Pole; Allan Hills; Dome A; South Pole Basin", "north": -84.0, "nsf_funding_programs": "Antarctic Glaciology", "persons": "Young, Duncan A.; Singh, Shivangini; Kerr, Megan E.; Buhl, Dillon P.; Ng, Gregory; Kempf, Scott D.; Blankenship, Donald D.; Young, Duncan", "project_titles": "Center for Oldest Ice Exploration", "projects": [{"proj_uid": "p0010321", "repository": "USAP-DC", "title": "Center for Oldest Ice Exploration"}], "repo": "USAP-DC", "repositories": "USAP-DC", "science_programs": null, "south": -90.0, "title": "NSF COLDEX 2023-24 GNSS/IMU Level 1 instrument measurements from Dome A, East Antarctica", "uid": "601999", "west": 0.0}, {"awards": "2019719 Brook, Edward", "bounds_geometry": null, "date_created": "Thu, 02 Oct 2025 00:00:00 GMT", "description": "The accumulation rate for the COLDEX airborne survey is derived from the shallowest, extensively traceable radar layer dated to 4.7 ka.", "east": null, "geometry": null, "keywords": "Antarctica; Coldex; Cryosphere; Glaciers/ice Sheet; Glaciers/Ice Sheet; Glaciology; Glaciology; Radar; Snow/ice; Snow/Ice", "locations": "Antarctica", "north": null, "nsf_funding_programs": "Antarctic Glaciology", "persons": "Fudge, T. J.", "project_titles": "Center for Oldest Ice Exploration", "projects": [{"proj_uid": "p0010321", "repository": "USAP-DC", "title": "Center for Oldest Ice Exploration"}], "repo": "USAP-DC", "repositories": "USAP-DC", "science_programs": "COLDEX", "south": null, "title": "COLDEX survey preliminary accumulation", "uid": "601994", "west": null}, {"awards": "2019719 Brook, Edward", "bounds_geometry": ["POLYGON((50 -84,55 -84,60 -84,65 -84,70 -84,75 -84,80 -84,85 -84,90 -84,95 -84,100 -84,100 -84.6,100 -85.2,100 -85.8,100 -86.4,100 -87,100 -87.6,100 -88.2,100 -88.8,100 -89.4,100 -90,95 -90,90 -90,85 -90,80 -90,75 -90,70 -90,65 -90,60 -90,55 -90,50 -90,50 -89.4,50 -88.8,50 -88.2,50 -87.6,50 -87,50 -86.4,50 -85.8,50 -85.2,50 -84.6,50 -84))"], "date_created": "Thu, 07 Aug 2025 00:00:00 GMT", "description": "This dataset provides the fractional thickness of incoherent scattering within the basal unit (relative to basal unit thickness) as measured by the NSF COLDEX MARFA ice-penetrating radar survey, which mainly focuses on the southern flank of Dome A. Raw radar data can be found at: https://doi.org/10.15784/601768. The basal unit thickness data can be found at: https://doi.org/10.15784/601912. The radar feature tracing and mapping is conducted with the DecisionSpace Geosciences 10ep software package. ", "east": 100.0, "geometry": ["POINT(75 -87)"], "keywords": "Antarctica; Coldex; Cryosphere; East Antarctic Plateau; Glaciers/ice Sheet; Glaciers/Ice Sheet; Glaciology; Ice Penetrating Radar", "locations": "East Antarctic Plateau; Antarctica", "north": -84.0, "nsf_funding_programs": "Antarctic Glaciology", "persons": "Yan, Shuai; Blankenship, Donald D.; Singh, Shivangini; Vega Gonzalez, Alejandra; Li, Duyi; Young, Duncan A.; Kerr, Megan E.", "project_titles": "Center for Oldest Ice Exploration", "projects": [{"proj_uid": "p0010321", "repository": "USAP-DC", "title": "Center for Oldest Ice Exploration"}], "repo": "USAP-DC", "repositories": "USAP-DC", "science_programs": "COLDEX", "south": -90.0, "title": "Fractional Thickness of Incoherent Scattering Within the Basal Unit Mapped by the NSF COLDEX MARFA Ice-Penetrating Radar", "uid": "601972", "west": 50.0}, {"awards": "2019719 Brook, Edward", "bounds_geometry": ["POLYGON((-109 -83,-84.4 -83,-59.8 -83,-35.19999999999999 -83,-10.599999999999994 -83,14 -83,38.60000000000002 -83,63.20000000000002 -83,87.80000000000001 -83,112.4 -83,137 -83,137 -83.7,137 -84.4,137 -85.1,137 -85.8,137 -86.5,137 -87.2,137 -87.9,137 -88.6,137 -89.3,137 -90,112.4 -90,87.8 -90,63.19999999999999 -90,38.599999999999994 -90,14 -90,-10.600000000000023 -90,-35.20000000000002 -90,-59.80000000000001 -90,-84.4 -90,-109 -90,-109 -89.3,-109 -88.6,-109 -87.9,-109 -87.2,-109 -86.5,-109 -85.8,-109 -85.1,-109 -84.4,-109 -83.7,-109 -83))"], "date_created": "Wed, 21 May 2025 00:00:00 GMT", "description": "These data comprise the RINEX formatted GNSS observations for flights in the 2022-2023 COLDEX field campaign, as well as the raw Novatel SPAN logs with rotation and acceleration information. The survey aircraft, Basler C-FMKB, had three GPS antennas (MKB2, MKB3, and MKB4) mounted on each wing and on the tail, and a single GNSS antenna (MKB1) mounted on roof near the center of gravity of the aircraft. Multiple receivers can be on each antenna. Data was recorded by a Javad Quattro-G3D (JVD) on all four antennas at 1 Hz, and on the wing antennas at 10 Hz, the Novatel SPAN OEM4 (NVT) on MKB1 at 1 Hz, and two Topcon NET-G3A (TG3) on the tail and one wing at 10 Hz. A 2 Hz Trimble Net R5 on the ground was operated for most flights (ZWD1 at Williams Field, or ZSP1 at South Pole), along with high rate Earthscope data from South Pole Station (AMU2).\r\n\u003cbr/\u003e\r\n\u003cbr/\u003eData is organized in a hierarchy with the following levels:\r\n\u003cbr/\u003e*Instrument type\r\n\u003cbr/\u003e*Flight\r\n\u003cbr/\u003e*Season \r\n\u003cbr/\u003e*Receiver (designated by antenna)\r\n\u003cbr/\u003e*Flight\r\n\u003cbr/\u003e*UTIG Stream name\r\n\u003cbr/\u003e\r\n\u003cbr/\u003eASCII RINEX data are generated by UNAVCO\u2019s teqc program and include:\r\n\u003cbr/\u003e*nav - GPS Nav Data\r\n\u003cbr/\u003e*rnv - GLONASS Nav Data\r\n\u003cbr/\u003e*obs - GPS Observation data\r\n\u003cbr/\u003e\r\n\u003cbr/\u003e_________________________________________________________________________\r\n\u003cbr/\u003e\r\n\u003cbr/\u003eSPAN data are binary files containing both the NVT GPS data that is reformatted as RINEX above, but also IMU messages. Formats for these OEM4 data can be found at Novatel\u2019s website: https://hexagondownloads.blob.core.windows.net/public/Novatel/assets/Documents/Manuals/om-20000047/om-20000047.pdf", "east": 137.0, "geometry": ["POINT(14 -86.5)"], "keywords": "Aerogeophysics; Antarctica; Cryosphere; South Pole", "locations": "South Pole; Antarctica", "north": -83.0, "nsf_funding_programs": "Antarctic Glaciology", "persons": "Young, Duncan A.; Greenbaum, Jamin Stevens; Chan, Kristian; Echeverry, Gonzalo; Singh, Shivangini; Ng, Gregory; Kempf, Scott D.; Blankenship, Donald D.; Young, Duncan; Buhl, Dillon P.; Kerr, Megan E.", "project_titles": "Center for Oldest Ice Exploration", "projects": [{"proj_uid": "p0010321", "repository": "USAP-DC", "title": "Center for Oldest Ice Exploration"}], "repo": "USAP-DC", "repositories": "USAP-DC", "science_programs": "COLDEX", "south": -90.0, "title": "NSF COLDEX 2022-23 GNSS/IMU Level 1 instrument measurements from Dome A, East Antarctica", "uid": "601933", "west": -109.0}, {"awards": "2019719 Brook, Edward", "bounds_geometry": ["POLYGON((50 -84,55 -84,60 -84,65 -84,70 -84,75 -84,80 -84,85 -84,90 -84,95 -84,100 -84,100 -84.6,100 -85.2,100 -85.8,100 -86.4,100 -87,100 -87.6,100 -88.2,100 -88.8,100 -89.4,100 -90,95 -90,90 -90,85 -90,80 -90,75 -90,70 -90,65 -90,60 -90,55 -90,50 -90,50 -89.4,50 -88.8,50 -88.2,50 -87.6,50 -87,50 -86.4,50 -85.8,50 -85.2,50 -84.6,50 -84))"], "date_created": "Mon, 10 Mar 2025 00:00:00 GMT", "description": "This dataset contains the basal ice unit thickness as measured by the NSF COLDEX MARFA ice-penetrating radar survey, which mainly focuses on the southern flank of Dome A. The \"basal ice unit\" is hereby defined as the bottom portion of the ice sheet where no clear and traceable englacial reflection is detected by the radar sounder. Raw radar data can be found at: https://doi.org/10.15784/601768. The basal ice unit is mapped using the DecisionSpace Geosciences 10ep software package. This dataset provides three data products:\r\n\u003cbr/\u003e\u2022 Thickness of the basal ice unit\r\n\u003cbr/\u003e\u2022 Thickness of the stratigraphic ice unit above the basal ice unit\r\n\u003cbr/\u003e\u2022 The shape of the basal ice unit boundary, where rapid basal ice unit thinning is observed in the middle of the South Pole Basin.", "east": 100.0, "geometry": ["POINT(75 -87)"], "keywords": "Antarctica; Coldex; Cryosphere; East Antarctica; East Antarctic Plateau; Glaciology; Radar Echo Sounder", "locations": "East Antarctic Plateau; East Antarctica; Antarctica", "north": -84.0, "nsf_funding_programs": "Antarctic Glaciology", "persons": "Yan, Shuai; Young, Duncan A.; Vega Gonzalez, Alejandra; Singh, Shivangini; Blankenship, Donald D.; Kerr, Megan E.", "project_titles": "Center for Oldest Ice Exploration", "projects": [{"proj_uid": "p0010321", "repository": "USAP-DC", "title": "Center for Oldest Ice Exploration"}], "repo": "USAP-DC", "repositories": "USAP-DC", "science_programs": "COLDEX", "south": -90.0, "title": "Basal Ice Unit Thickness Mapped by the NSF COLDEX MARFA Ice Penetrating Radar", "uid": "601912", "west": 50.0}, {"awards": "2019719 Brook, Edward", "bounds_geometry": ["POLYGON((158 -75,158.2 -75,158.4 -75,158.6 -75,158.8 -75,159 -75,159.2 -75,159.4 -75,159.6 -75,159.8 -75,160 -75,160 -75.2,160 -75.4,160 -75.6,160 -75.8,160 -76,160 -76.2,160 -76.4,160 -76.6,160 -76.8,160 -77,159.8 -77,159.6 -77,159.4 -77,159.2 -77,159 -77,158.8 -77,158.6 -77,158.4 -77,158.2 -77,158 -77,158 -76.8,158 -76.6,158 -76.4,158 -76.2,158 -76,158 -75.8,158 -75.6,158 -75.4,158 -75.2,158 -75))"], "date_created": "Thu, 15 Aug 2024 00:00:00 GMT", "description": "Field report for Allan Hills ice core drilling and geophysics, field season 2023-2024", "east": 160.0, "geometry": ["POINT(159 -76)"], "keywords": "Allan Hills; Antarctica; Coldex; Cryosphere", "locations": "Allan Hills; Antarctica", "north": -75.0, "nsf_funding_programs": "Antarctic Glaciology", "persons": "Marks Peterson, Julia; Higgins, John; Brook, Edward J.; Shackleton, Sarah; Carter, Austin; Manos, John-Morgan; Hudak, Abigail; Banerjee, Asmita; Morton, Elizabeth; Jayred, Michael; Goverman, Ashley; Mayo, Emalia; Epifanio, Jenna", "project_titles": "Center for Oldest Ice Exploration", "projects": [{"proj_uid": "p0010321", "repository": "USAP-DC", "title": "Center for Oldest Ice Exploration"}], "repo": "USAP-DC", "repositories": "USAP-DC", "science_programs": "COLDEX", "south": -77.0, "title": "2023-2024 Allan Hills End-of-Season Science Report", "uid": "601824", "west": 158.0}, {"awards": "2019719 Brook, Edward", "bounds_geometry": ["POLYGON((50 -84,55 -84,60 -84,65 -84,70 -84,75 -84,80 -84,85 -84,90 -84,95 -84,100 -84,100 -84.6,100 -85.2,100 -85.8,100 -86.4,100 -87,100 -87.6,100 -88.2,100 -88.8,100 -89.4,100 -90,95 -90,90 -90,85 -90,80 -90,75 -90,70 -90,65 -90,60 -90,55 -90,50 -90,50 -89.4,50 -88.8,50 -88.2,50 -87.6,50 -87,50 -86.4,50 -85.8,50 -85.2,50 -84.6,50 -84))"], "date_created": "Mon, 19 Feb 2024 00:00:00 GMT", "description": "This dataset constitutes the as-recorded echo data from the MARFA radar system. The data was recorded by a National Instruments acquisition system, simultaneously with GPS, magnetics, laser range data, outside air temperature and IMU data. The data was acquired using the Environment for Linked Serial Acquisition (ELSA).\r\n\r\nThe data is provided in two forms: \r\n\u2022 Flight based and as recorded on the aircraft in raw packets\r\n\u2022 Transect based, reorganized into transects corresponding to the survey design, and demultiplexed into text tables and flat binary files.\r\n", "east": 100.0, "geometry": ["POINT(75 -87)"], "keywords": "Antarctica; Coldex; East Antarctic Plateau; Glaciology; Radar Echo Sounder", "locations": "Antarctica; East Antarctic Plateau", "north": -84.0, "nsf_funding_programs": "Antarctic Glaciology", "persons": "Young, Duncan A.; Blankenship, Donald D.; Greenbaum, Jamin; Ng, Gregory; Kempf, Scott D.; Chan, Kristian; Kerr, Megan E.; Buhl, Dillon P.", "project_titles": "Center for Oldest Ice Exploration", "projects": [{"proj_uid": "p0010321", "repository": "USAP-DC", "title": "Center for Oldest Ice Exploration"}], "repo": "USAP-DC", "repositories": "USAP-DC", "science_programs": "COLDEX", "south": -90.0, "title": "NSF COLDEX Raw MARFA Ice Penetrating Radar data", "uid": "601768", "west": 50.0}, {"awards": "2019719 Brook, Edward", "bounds_geometry": ["POLYGON((159.17 -76.67,159.195 -76.67,159.22 -76.67,159.24499999999998 -76.67,159.26999999999998 -76.67,159.295 -76.67,159.32 -76.67,159.345 -76.67,159.36999999999998 -76.67,159.39499999999998 -76.67,159.42 -76.67,159.42 -76.676,159.42 -76.682,159.42 -76.688,159.42 -76.694,159.42 -76.7,159.42 -76.706,159.42 -76.712,159.42 -76.718,159.42 -76.724,159.42 -76.73,159.39499999999998 -76.73,159.36999999999998 -76.73,159.345 -76.73,159.32 -76.73,159.295 -76.73,159.26999999999998 -76.73,159.24499999999998 -76.73,159.22 -76.73,159.195 -76.73,159.17 -76.73,159.17 -76.724,159.17 -76.718,159.17 -76.712,159.17 -76.706,159.17 -76.7,159.17 -76.694,159.17 -76.688,159.17 -76.682,159.17 -76.676,159.17 -76.67))"], "date_created": "Fri, 16 Jun 2023 00:00:00 GMT", "description": "This unpublished report describes field activities in the 2022-23 Antarctic field season by the I-188 group within COLDEX. The main purpose of this work was to identify the final coring site for a proposed 1250 m ice core. ", "east": 159.42, "geometry": ["POINT(159.295 -76.7)"], "keywords": "Allan Hills; Antarctica; Apres; Ice Core; Ice Penetrating Radar; Temperature Profiles", "locations": "Allan Hills; Antarctica", "north": -76.67, "nsf_funding_programs": "Antarctic Glaciology", "persons": "Conway, Howard; Brook, Edward J.", "project_titles": "Center for Oldest Ice Exploration", "projects": [{"proj_uid": "p0010321", "repository": "USAP-DC", "title": "Center for Oldest Ice Exploration"}], "repo": "USAP-DC", "repositories": "USAP-DC", "science_programs": "COLDEX", "south": -76.73, "title": "2022-23 Allan Hills Intermediate Ice Core Site Selection Field Report", "uid": "601697", "west": 159.17}]

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