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  • 1
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    Ice thickness from the Dome Fuji region, East Antarctica from ice-penetrating radar (2018)
    PANGAEA
    In:  Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research, Bremerhaven | Supplement to: Karlsson, Nanna Bjørnholt; Binder, Tobias; Eagles, Graeme; Helm, Veit; Pattyn, Frank; Van Liefferinge, Brice; Eisen, Olaf (2018): Glaciological characteristics in the Dome Fuji region and new assessment for “Oldest Ice”. The Cryosphere, 12(7), 2413-2424, https://doi.org/10.5194/tc-12-2413-2018
    Details
    Publication Date: 2024-02-16
    Description: Here, we present new ice thickness information from the Dome Fuji region, East Antarctica, based on airborne radar surveys conducted during the 2014/15 and 2016/17 southern summers. The data are merged with older airborne surveys conducted by the Alfred Wegener Institute, Germany (in 2003) and the Japanese National Polar Institute (1990s and 2000s). Compared to previous maps of the region, the new dataset shows a more complex landscape with networks of valleys and mountain plateaus. We provide two datasets; one in 1km resolution for the whole study region and a 500m resolution for the area in the immediate vicinity of Dome Fuji. The projection is polar stereographic, centered on 0E, 90S with true scale at 70S.
    Keywords: Dome_Fuji_area; MULT; Multiple investigations
    Type: Dataset
    Format: application/zip, 8.1 MBytes
    Location Call Number Limitation Availability
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    DATA PANGAEA
  • 2
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    Modelling the Antarctic Ice Sheet across the mid-Pleistocene transition – implications for Oldest Ice (2019)
    Copernicus Publications (EGU)
    In:  The Cryosphere, 13 (7). pp. 2023-2041.
    Details
    Publication Date: 2021-01-08
    Description: The international endeavour to retrieve a continuous ice core, which spans the middle Pleistocene climate transition ca. 1.2–0.9 Myr ago, encompasses a multitude of field and model-based pre-site surveys. We expand on the current efforts to locate a suitable drilling site for the oldest Antarctic ice core by means of 3-D continental ice-sheet modelling. To this end, we present an ensemble of ice-sheet simulations spanning the last 2 Myr, employing transient boundary conditions derived from climate modelling and climate proxy records. We discuss the imprint of changing climate conditions, sea level and geothermal heat flux on the ice thickness, and basal conditions around previously identified sites with continuous records of old ice. Our modelling results show a range of configurational ice-sheet changes across the middle Pleistocene transition, suggesting a potential shift of the West Antarctic Ice Sheet to a marine-based configuration. Despite the middle Pleistocene climate reorganisation and associated ice-dynamic changes, we identify several regions conducive to conditions maintaining 1.5 Myr (million years) old ice, particularly around Dome Fuji, Dome C and Ridge B, which is in agreement with previous studies. This finding strengthens the notion that continuous records with such old ice do exist in previously identified regions, while we are also providing a dynamic continental ice-sheet context.
    Type: Article , PeerReviewed
    Format: text
    DOI: 10.5194/tc-13-2023-2019
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    OceanRep: Article in a Scientific Journal - peer-reviewed
  • 3
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    The climate memory of an Arctic polythermal glacier (2014)
    Cambridge University Press
    Details
    Publication Date: 2014-01-31
    Print ISSN: 0022-1430
    Electronic ISSN: 1727-5652
    Topics: Geography , Geosciences
    Published by Cambridge University Press on behalf of The International Glaciological Society (IGS).
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    PAPER CURRENT
  • 4
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    Promising Oldest Ice sites in East Antarctica based on thermodynamical modelling (2018)
    In:  EPIC3EGU General Assembly, Vienna, 2018-04-08-2018-04-13
    Details
    Publication Date: 2019-08-21
    Description: To resolve the mechanisms behind the major climate reorganisation which occurred between 0.9 and 1.2 Ma, the recovery of a suitable 1.5 million-year-old ice core is fundamental. The quest for such an Oldest Ice core requires a number of key boundary conditions, of which the poorly known basal geothermal heat flux (GHF) is lacking. We use a transient thermodynamical 1D vertical model that solves for the rate of change of temperature in the vertical, with surface temperature and modelled GHF as boundary conditions. For each point on the ice sheet, the model is forced with variations in atmospheric conditions over the last 2 Ma, and modelled ice-thickness variations. The process is repeated for a range of GHF values to determine the value of GHF that marks the limit between frozen and melting conditions over the whole ice sheet, taking into account 2 Ma of climate history. These threshold values of GHF are statistically compared to existing GHF data sets. The new probabilistic GHF fields obtained for the ice sheet thus provide the missing boundary conditions in the search for Oldest Ice. High spatial resolution radar data are examined locally in the Dome Fuji and Dome C regions, as these represent the ice core community’s primary drilling sites. GHF, bedrock variability, ice thickness and other essential criteria combined highlight a dozen major potential Oldest Ice sites in the vicinity of Dome Fuji and Dome C, where GHF allows for Oldest Ice.
    Repository Name: EPIC Alfred Wegener Institut
    Type: Conference , notRev
    Format: application/pdf
    Location Call Number Limitation Availability
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    PAPER (OA)
  • 5
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    Modelling the Antarctic Ice Sheet across the mid-Pleistocene transition – implications for Oldest Ice (2019)
    In:  EPIC3The Cryosphere, 13(7), pp. 2023-2041, ISSN: 1994-0424
    Details
    Publication Date: 2019-08-19
    Description: The international endeavour to retrieve a continuous ice core, which spans the middle Pleistocene climate transition ca. 1.2–0.9 Myr ago, encompasses a multitude of field and model-based pre-site surveys. We expand on the current efforts to locate a suitable drilling site for the oldest Antarctic ice core by means of 3-D continental ice-sheet modelling. To this end, we present an ensemble of ice-sheet simulations spanning the last 2 Myr, employing transient boundary conditions derived from climate modelling and climate proxy records. We discuss the imprint of changing climate conditions, sea level and geothermal heat flux on the ice thickness, and basal conditions around previously identified sites with continuous records of old ice. Our modelling results show a range of configurational ice-sheet changes across the middle Pleistocene transition, suggesting a potential shift of the West Antarctic Ice Sheet to a marine-based configuration. Despite the middle Pleistocene climate reorganisation and associated ice-dynamic changes, we identify several regions conducive to conditions maintaining 1.5 Myr (million years) old ice, particularly around Dome Fuji, Dome C and Ridge B, which is in agreement with previous studies. This finding strengthens the notion that continuous records with such old ice do exist in previously identified regions, while we are also providing a dynamic continental ice-sheet context.
    Repository Name: EPIC Alfred Wegener Institut
    Type: Article , isiRev , info:eu-repo/semantics/article
    Format: application/pdf
    Location Call Number Limitation Availability
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    PAPER (OA)
  • 6
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    A Mobile, Multichannel, UWB Radar for Potential Ice Core Drill Site Identification in East Antarctica: Development and First Results (2020)
    IEEE
    In:  EPIC3IEEE JOURNAL OF SELECTED TOPICS IN APPLIED EARTH OBSERVATIONS AND REMOTE SENSING,, IEEE, 13, pp. 4836-4847, ISSN: 2473-2397 / 2168-6831
    Details
    Publication Date: 2020-09-07
    Description: We developed a high-performance, multichannel, ultra-wideband radar system for measurements of the base and interior of the East Antarctic Ice Sheet. We designed the radar to be of high power (4000-W peak) yet portable and to be able to operate with 60-MHz bandwidth at a center frequency of 200 MHz, providing high sensitivity and fine vertical resolution relative to current technology. We used the radar to perform extensive mea- surements as a part of a multinational collaboration. We collected data onboard a tracked vehicle outfitted with an array of high-gain antennas. We sounded 2- to 3-km thick ice near Dome Fuji. Prelim- inary ice thickness data match those obtained via semicoincident measurements performed with a different surface-based pulse- modulated radar system operated during the same field campaign, as well as previous airborne measurements. In addition, we mapped internal reflection horizons with fine vertical resolution from 300 m below the ice surface to ∼100 m above the bed. In this article, we provide a detailed overview of the radar instrument design, implementation, and field measurement setup. We present sample data to illustrate its capabilities and discuss how the data collected with it will be valuable for the assessment of promising drilling sites to recover ice cores that are 0.9–1.5 million years old.
    Repository Name: EPIC Alfred Wegener Institut
    Type: Article , isiRev
    Format: application/pdf
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    PAPER (OA)
  • 7
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    Glaciological characteristics in the Dome Fuji region and new assessment for “Oldest Ice” (2018)
    In:  EPIC3The Cryosphere, 12(7), pp. 2413-2424, ISSN: 1994-0424
    Details
    Publication Date: 2018-07-26
    Description: A key objective in palaeo-climatology is the retrieval of a continuous Antarctic ice-core record dating back 1.5 Ma. The identification of a suitable Antarctic site requires sufficient knowledge of the subglacial landscape beneath the Antarctic Ice Sheet. Here, we present new ice thickness information from the Dome Fuji region, East Antarctica, based on airborne radar surveys conducted during the 2014/15 and 2016/17 southern summers. Compared to previous maps of the region, the new dataset shows a more complex landscape with networks of valleys and mountain plateaus. We use the new dataset as input in a thermokinematic model that incorporates uncertainties in geothermal heat flux values in order to improve the predictions of potential ice-core sites. Our results show that especially the region immediately south of Dome Fuji station persists as a good candidate site for obtaining an old ice core. An initial assessment of basal conditions revealed the existence of what appears to be subglacial lakes. Further radar data analysis shows overall high continuity of layer stratigraphy in the region. This indicates that extending the age–depth information from the Dome Fuji ice core to a new ice-core drill site is a viable option.
    Repository Name: EPIC Alfred Wegener Institut
    Type: Article , isiRev
    Format: application/pdf
    Location Call Number Limitation Availability
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    PAPER (OA)
  • 8
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    Promising Oldest Ice sites in East Antarctica based on thermodynamical modelling (2018)
    Copernicus
    In:  EPIC3The Cryosphere Discussions, Copernicus, pp. 1-22, ISSN: 1994-0440
    Details
    Publication Date: 2018-08-20
    Description: To resolve the mechanisms behind the major climate reorganisation which occurred between 0.9 and 1.2Ma, the recovery of a suitable 1.5 million-year-old ice core is fundamental. The quest for such an Oldest Ice core requires a number of key boundary conditions, of which the poorly known basal geothermal heat flux (GHF) is lacking. We use a transient thermodynamical 1D vertical model that solves for the rate of change of temperature in the vertical, with surface temperature and modelled GHF as boundary conditions. For each point on the ice sheet, the model is forced with variations in atmospheric conditions over the last 2Ma, and modelled ice-thickness variations. The process is repeated for a range of GHF values to determine the value of GHF that marks the limit between frozen and melting conditions over the whole ice sheet, taking into account 2Ma of climate history. These threshold values of GHF are statistically compared to existing GHF data sets. The new probabilistic GHF fields obtained for the ice sheet thus provide the missing boundary conditions in the search for Oldest Ice. High spatial resolution radar data are examined locally in the Dome Fuji and Dome C regions, as these represent the ice core community's primary drilling sites. GHF, bedrock variability, ice thickness and other essential criteria combined highlight a dozen major potential Oldest Ice sites in the vicinity of Dome Fuji and Dome C, where GHF allows for Oldest Ice.
    Repository Name: EPIC Alfred Wegener Institut
    Type: Article , notRev , info:eu-repo/semantics/article
    Format: application/pdf
    Location Call Number Limitation Availability
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    PAPER (OA)
  • 9
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    Bed diagnosis in the Dome Fuji region, East Antarctica, using airborneradar data and englacial attenuation estimates (2019)
    In:  EPIC3EGU General Assembly, Vienna, 2019-04-07-2019-04-12
    Details
    Publication Date: 2019-08-21
    Description: Radar reflectivity of the ice-sheet bed has been used as a diagnostic measure of the basal conditions. Such bed diagnosis could lead to constrain magnitude and spatial pattern of geothermal flux which remains poorly known under the Antarctic Ice Sheet. Radar reflectivity can be estimated from the radar-observed bed returned power by extracting englacial attenuation. Attenuation exponentially depends on ice temperature, and can vary larger than the difference in the bed reflectivity for thawed and dry beds. In the 2016-17 austral summer, Alfred Wegener Institute carried out 150-MHz airborne radar survey for∼19,000 line kilometers in a 400-km by 400-km area including Dome Fuji, East Antarctica, where the Oldest Ice is predicted to present. Bed topography, roughness, and subglacial hydraulic potential were analyzed and subglacial lakes were preliminary mapped. We extend that study by rigorous analysis of bed returned power. We hypothesize that model-predicted thawed area is consistent with high bed reflectivity area derived from the radar data, when englacial attenuation/temperature is derived for the correct geothermal flux. We carried out attenuation and radar reflectivity estimates for a range of geothermalflux and mapped spatial variations in the attenuation and bed reflectivity.
    Repository Name: EPIC Alfred Wegener Institut
    Type: Conference , notRev
    Format: application/pdf
    Location Call Number Limitation Availability
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    PAPER (OA)
  • 10
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    Glaciological characteristics in the Dome Fuji region and new assessment for 1.5 Ma old ice (2018)
    In:  EPIC3EGU General Assembly, Vienna, 2018-04-08-2018-04-13
    Details
    Publication Date: 2019-08-21
    Description: The retrieval of a continuous Antarctic ice-core record dating back 1.5 Ma is a key objective in palaeo-climatologyin order to understand why the frequency of ice ages changed from 40 ka to 100 ka approximately 1 Ma ago. Here,we investigate the probability that the Dome Fuji region in East Antarctica contains ice more than 1.5 Ma old.We use a new radar dataset acquired in the Antarctic seasons 2014/15 and 2016/17 to improve the ice thickness map. Compared to previous maps of the region, the new dataset shows a more complex landscape with networks of valleys and mountain plateaus. We use the new dataset as input in a thermokinematic model that incorporates uncertainties in geothermal heat flux values in order to improve the predictions of potential ice-core sites. Our results indicate several areas of interest, especially the region immediately south of Dome Fuji station appears to be a good candidate site. An initial assessment of basal conditions revealed the existence of several wet-based areas and further radar data analysis shows overall high continuity of layer stratigraphy in the region. Thus, if a new drill operation were to take place in this area, extending the age-depth information from the Dome Fuji ice core to a new ice-core drill site is a viable option.
    Repository Name: EPIC Alfred Wegener Institut
    Type: Conference , notRev
    Format: application/pdf
    Location Call Number Limitation Availability
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    PAPER (OA)
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