GLORIA

GEOMAR Library Ocean Research Information Access

X
feed icon rss

Ihre E-Mail wurde erfolgreich gesendet. Bitte prüfen Sie Ihren Maileingang.

Leider ist ein Fehler beim E-Mail-Versand aufgetreten. Bitte versuchen Sie es erneut.

Vorgang fortführen?

Exportieren
  • 1
    facet.materialart.
    Unbekannt
    Basal age, surface accumulation, basal melting, geothermal flux and Lliboutry exponent of the velocity profile in the Dome C area (2017)
    PANGAEA
    In:  Supplement to: Parrenin, Frédéric; Cavitte, Marie G P; Blankenship, Donald D; Chappellaz, Jérôme A; Fischer, Hubertus; Gagliardini, Olivier; Masson-Delmotte, Valerie; Passalacqua, Olivier; Ritz, Catherine; Roberts, Jason L; Siegert, Martin J; Young, Duncan A (2017): Is there 1.5-million-year-old ice near Dome C, Antarctica? The Cryosphere, 11(6), 2427-2437, https://doi.org/10.5194/tc-11-2427-2017
    Details
    Publikationsdatum: 2023-03-31
    Beschreibung: Ice sheets provide exceptional archives of past changes in polar climate, regional environment and global atmospheric composition. The oldest dated deep ice core drilled in Antarctica has been retrieved at EPICA Dome C (EDC), reaching ~800,000 years. Obtaining an older paleoclimatic record from Antarctica is one of the greatest challenges of the ice core community. Here, we use internal isochrones, identified from airborne radar coupled to ice-flow modelling to estimate the age of basal ice along transects in the Dome C area. Three glaciological properties are inverted from isochrones: surface accumulation rate; geothermal flux; and the exponent of the Lliboutry velocity profile. We find that old ice (〉1 Myr, 1 million years) likely exists in two regions: one ~40 km south-west of Dome C along the ice divide to Vostok, close to a secondary dome that we name "Little Dome C" (LDC); and a second region named "North Patch" (NP) located 10-30 km north-east of Dome C, in a region where the geothermal flux is apparently relatively low. Our work demonstrates the value of combining radar observations with ice flow modelling to accurately represent the true nature of ice flow, and the formation of ice-sheet architecture, in the centre of large ice sheets.
    Schlagwort(e): Accumulation rate, standard deviation; Accumulation rate in ice equivalent per year; AGE; Antarctica; Distance; DomeC_area; Factor; Ground heat, flux; Ground heat, flux, standard deviation; Height; Ice thickness; LATITUDE; LONGITUDE; Melt rate; Melt rate, standard deviation; MULT; Multiple investigations; Number of years; Standard deviation
    Materialart: Dataset
    Format: text/tab-separated-values, 95189 data points
    Standort Signatur Einschränkungen Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    DATA PANGAEA
  • 2
    facet.materialart.
    Unbekannt
    ADMAP2 Magnetic anomaly map of the Antarctic - links to files (2018)
    PANGAEA
    In:  Supplement to: Golynsky, Alexander V; Ferraccioli, Fausto; Hong, Jong Kuk; Golynsky, Dmitry A; von Frese, Ralph R B; Young, Duncan A; Blankenship, Donald D; Holt, John W; Ivanov, Sergey V; Kiselev, Alexander V; Masolov, Valery N; Eagles, Graeme; Gohl, Karsten; Jokat, Wilfried; Damaske, Detlef; Finn, Carol A; Aitken, Alan; Bell, Robin E; Armadillo, Egidio; Jordan, Tom A; Greenbaum, Jamin S; Bozzo, Emanuele; Caneva, Giorgio; Forsberg, René; Ghidella, Marta E; Galíndo-Zaldívar, Jesús; Bohoyo, Fernando; Martos, Yasmina M; Nogi, Yoshifumi; Quartini, Enrica; Kim, Hyung Rae; Roberts, Jason L (2018): New magnetic anomaly map of the Antarctic. Geophysical Research Letters, 45(13), 6437-6449, https://doi.org/10.1029/2018GL078153
    Details
    Publikationsdatum: 2023-01-13
    Beschreibung: ADMAP2 is the second generation Antarctic magnetic anomaly compilation for the region south of 60°S based on ship- and airborne magnetic anomaly measurements. The distribution comprises a set of full (ADMAP-2) and abridged (ADMAP-2A) databases organised by sub-region and/or survey in Geosoft format, and a set of Geosoft-format grids.
    Schlagwort(e): pan-Antarctica
    Materialart: Dataset
    Format: application/zip, 3 datasets
    Standort Signatur Einschränkungen Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    DATA PANGAEA
  • 3
    facet.materialart.
    Unbekannt
    ADMAP2 Magnetic anomaly map of the Antarctic - links to ADMAP2 gdb files (2018)
    PANGAEA
    Details
    Publikationsdatum: 2023-01-13
    Schlagwort(e): File content; File format; File name; File size; pan-Antarctica; Uniform resource locator/link to file
    Materialart: Dataset
    Format: text/tab-separated-values, 155 data points
    Standort Signatur Einschränkungen Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    DATA PANGAEA
  • 4
    facet.materialart.
    Unbekannt
    ADMAP2 Magnetic anomaly map of the Antarctic - links to ADMAP2A gdb files (2018)
    PANGAEA
    Details
    Publikationsdatum: 2023-01-13
    Schlagwort(e): File content; File format; File name; File size; pan-Antarctica; Uniform resource locator/link to file
    Materialart: Dataset
    Format: text/tab-separated-values, 165 data points
    Standort Signatur Einschränkungen Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    DATA PANGAEA
  • 5
    facet.materialart.
    Unbekannt
    ADMAP2 Magnetic anomaly map of the Antarctic - links to grid (grd) files (2018)
    PANGAEA
    Details
    Publikationsdatum: 2023-01-13
    Schlagwort(e): File content; File format; File name; File size; pan-Antarctica; Uniform resource locator/link to file
    Materialart: Dataset
    Format: text/tab-separated-values, 190 data points
    Standort Signatur Einschränkungen Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    DATA PANGAEA
  • 6
    facet.materialart.
    Unbekannt
    Antarctic free-air and complete Bouguer gravity anomaly grid (2016)
    PANGAEA
    In:  Supplement to: Scheinert, Mirko; Ferraccioli, Fausto; Schwabe, Joachim; Bell, Robin E; Studinger, Michael; Damaske, Detlef; Jokat, Wilfried; Aleshkova, Nadezhda D; Jordan, Tom A; Leitchenkov, German L; Blankenship, Donald D; Damiani, Theresa; Young, Duncan A; Cochran, James R; Richter, Thomas (2016): New Antarctic gravity anomaly grid for enhanced geodetic and geophysical studies in Antarctica. Geophysical Research Letters, 43(2), 600-610, https://doi.org/10.1002/2015GL067439
    Details
    Publikationsdatum: 2023-08-24
    Beschreibung: Gravity surveying is challenging in Antarctica because of its hostile environment and inaccessibility. Nevertheless, many ground-based, airborne, and shipborne gravity campaigns have been completed by the geophysical and geodetic communities since the 1980s. We present the first modern Antarctic-wide gravity data compilation derived from 13 million data points covering an area of 10 million km**2, which corresponds to 73% coverage of the continent. The remove-compute-restore technique was applied for gridding, which facilitated leveling of the different gravity data sets with respect to an Earth gravity model derived from satellite data alone. The resulting free-air and Bouguer gravity anomaly grids of 10 km resolution are publicly available. These grids will enable new high-resolution combined Earth gravity models to be derived and represent a major step forward toward solving the geodetic polar data gap problem. They provide a new tool to investigate continental-scale lithospheric structure and geological evolution of Antarctica.
    Schlagwort(e): Accuracy; Bouguer anomaly; Free-air gravity anomaly; Height above ellipsoid; LATITUDE; LONGITUDE; Orthometric height; pan-Antarctica; x; y
    Materialart: Dataset
    Format: text/tab-separated-values, 2224256 data points
    Standort Signatur Einschränkungen Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    DATA PANGAEA
  • 7
    facet.materialart.
    Unbekannt
    (Supplement 3) Radar sounding observations including bedrock and surface elevation and ice thickness in the ASB region, Antarctica (2011)
    PANGAEA
    In:  Supplement to: Young, Duncan A; Wright, Andrew P; Roberts, Jason L; Warner, Roland C; Young, Neal W; Greenbaum, Jamin S; Schroeder, Dustin M; Holt, John W; Sugden, David E; Blankenship, Donald D; van Ommen, Tas D; Siegert, Martin J (2011): A dynamic early East Antarctic Ice Sheet suggested by ice-covered fjord landscapes. Nature, 474(7349), 72-75, https://doi.org/10.1038/nature10114
    Details
    Publikationsdatum: 2023-12-13
    Beschreibung: The first Cenozoic ice sheets initiated in Antarctica from the Gamburtsev Subglacial Mountains and other highlands as a result of rapid global cooling ~34 million years ago. In the subsequent 20 million years, at a time of declining atmospheric carbon dioxide concentrations and an evolving Antarctic circumpolar current, sedimentary sequence interpretation and numerical modelling suggest that cyclical periods of ice-sheet expansion to the continental margin, followed by retreat to the subglacial highlands, occurred up to thirty times. These fluctuations were paced by orbital changes and were a major influence on global sea levels. Ice-sheet models show that the nature of such oscillations is critically dependent on the pattern and extent of Antarctic topographic lowlands. Here we show that the basal topography of the Aurora Subglacial Basin of East Antarctica, at present overlain by 2-4.5 km of ice, is characterized by a series of well-defined topographic channels within a mountain block landscape. The identification of this fjord landscape, based on new data from ice-penetrating radar, provides an improved under¬standing of the topography of the Aurora Subglacial Basin and its surroundings, and reveals a complex surface sculpted by a succession of ice-sheet configurations substantially different from today's. At different stages during its fluctuations, the edge of the East Antarctic Ice Sheet lay pinned along the margins of the Aurora Subglacial Basin, the upland boundaries of which are currently above sea level and the deepest parts of which are more than 1 km below sea level. Although the timing of the channel incision remains uncertain, our results suggest that the fjord landscape was carved by at least two ice- flow regimes of different scales and directions, each of which would have over-deepened existing topographic depressions, reversing valley floor slopes.
    Schlagwort(e): Antarctica, East; ASB_HighlandAB; Distance; Elevation 2; Ice thickness; Identification; International Polar Year (2007-2008); IPY; LATITUDE; LONGITUDE; Surface elevation; Time in seconds
    Materialart: Dataset
    Format: text/tab-separated-values, 6436866 data points
    Standort Signatur Einschränkungen Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    DATA PANGAEA
  • 8
    facet.materialart.
    Unbekannt
    High-resolution boundary conditions of an old ice target near Dome C, Antarctica (2018)
    Details
    Publikationsdatum: 2020-10-13
    Beschreibung: A high-resolution (1 km line spacing) aerogeophysical survey was conducted over a region near the East Antarctic Ice Sheet’s Dome C that may hold a 1.5 Myr climate record. We combined new ice thickness data derived from an airborne coherent radar sounder with unpublished data that was in part unavailable for earlier compilations, and we were able to remove older data with high positional uncertainties. We generated a revised high-resolution digital elevation model (DEM) to investigate the potential for an old ice record in this region, and used laser altimetry to confirm a Cryosat-2 derived DEM for inferring the glaciological state of the candidate area. By measuring the specularity content of the bed, we were able to find an additional 50 subglacial lakes near the candidate site, and by Doppler focusing the radar data, we were able to map out the roughness of the bed at length scales of hundreds of meters. We find that the primary candidate region contains elevated rough topography interspersed with scattered subglacial lakes and some regions of smoother bed. Free subglacial water appears to be restricted from bed overlain by ice thicknesses of less than 3000 m. A site near the ice divide was selected for further investigation. The high resolution of this ice thickness data set also allows us to explore the nature of ice thickness uncertainties in the context of radar geometry and processing.
    Beschreibung: Published
    Beschreibung: 1897-1911
    Beschreibung: 5A. Paleoclima e ricerche polari
    Beschreibung: JCR Journal
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Materialart: article
    Standort Signatur Einschränkungen Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    ARTIKEL (OA)
  • 9
    facet.materialart.
    Unbekannt
    Promising Oldest Ice sites in East Antarctica based on thermodynamical modelling (2018)
    In:  EPIC3EGU General Assembly, Vienna, 2018-04-08-2018-04-13
    Details
    Publikationsdatum: 2019-08-21
    Beschreibung: 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
    Materialart: Conference , notRev
    Format: application/pdf
    Standort Signatur Einschränkungen Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    ARTIKEL (OA)
  • 10
    facet.materialart.
    Unbekannt
    AntArchitecture: an international project to use Antarctic englacial layering to interrogate stability of the Antarctic Ice Sheets (2019)
    In:  EPIC3IGS Symposium Five Decades of Radioglaciology, Stanford, California, USA, 2019-07-08-2019-07-12
    Details
    Publikationsdatum: 2019-08-12
    Beschreibung: ‘AntArchitecture’ is a new Action Group of the Scientific Committee for Antarctic Research that aims for the first time to determine the stability of the Antarctic ice sheets over past glacial cycles directly from the internal architecture of the ice. Internal architecture describes the 3D internal structure of the ice imaged by multiple radarâ-sounding surveys undertaken across Antarctica over the last five decades. AntArchitecture aspires to bring together the key datasets on Antarctic Ice Sheet internal layering from the principal institutions and scientists who have been responsible for acquiring, processing and storing them over the last four decades. Key activities include coordinating data-transfer and data-lodging exercises between institutions/countries that will allow datasets acquired by different radar systems to be combined for pan-ontinental analysis, and the development of an optimized processing flow for analysis of past data and advice on where future data acquisition needs to be targeted. An expanded outline of AntArchitecture and its timeline of activities can be accessed here: https://www.scar.org/science/antarchitecture/about/ This presentation provides a status report of activities and achievement of AntArchitecture to July 2019.
    Repository-Name: EPIC Alfred Wegener Institut
    Materialart: Conference , notRev
    Standort Signatur Einschränkungen Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    ARTIKEL (OA)
Schließen ⊗
Diese Webseite nutzt Cookies und das Analyse-Tool Matomo. Weitere Informationen finden Sie hier...