GLORIA

GEOMAR Library Ocean Research Information Access

X

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
Filter
  • International Glaciological Society  (4)
  • 1
    Online Resource
    Online Resource
    On the link between surface and basal structures of the Jelbart Ice Shelf, Antarctica
    International Glaciological Society ; 2015
    In:  Journal of Glaciology Vol. 61, No. 229 ( 2015), p. 975-986
    Details
    In: Journal of Glaciology, International Glaciological Society, Vol. 61, No. 229 ( 2015), p. 975-986
    Abstract: To understand the dynamics of ice shelves, a knowledge of their internal and basal structure is very important. As the capacity to perform local surveys is limited, remote sensing provides an opportunity to obtain the relevant information. We must prove, however, that the relevant information can be obtained from remote sensing of the surface. That is the aim of this study. The Jelbart Ice Shelf, Antarctica, exhibits a variety of surface structures appearing as stripe-like features in radar imagery. We performed an airborne geophysical survey across these features and compared the results to TerraSAR-X imagery. We find that the stripe-like structures indicate surface troughs coinciding with the location of basal channels and crevasse-like features, revealed by radio-echo sounding. HH and VV polarizations do not show different magnitude. In surface troughs, the local accumulation rate is larger than at the flat surface. Viscoelastic modelling is used to gain an understanding of the surface undulations and their origin. The surface displacement, computed with a Maxwell model, matches the observed surface reasonably well. Our simulations show that the surface troughs develop over decadal to centennial timescales.
    Type of Medium: Online Resource
    ISSN: 0022-1430 , 1727-5652
    URL: Article
    DOI: 10.3189/2015JoG15J023
    Language: English
    Publisher: International Glaciological Society
    Publication Date: 2015
    detail.hit.zdb_id: 2140541-4
    SSG: 14
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    Online Resource
  • 2
    Online Resource
    Online Resource
    Ku-band radar penetration into snow cover on Arctic sea ice using airborne data
    International Glaciological Society ; 2011
    In:  Annals of Glaciology Vol. 52, No. 57 ( 2011), p. 197-205
    Details
    In: Annals of Glaciology, International Glaciological Society, Vol. 52, No. 57 ( 2011), p. 197-205
    Abstract: Satellite radar altimetry provides data to monitor winter Arctic sea-ice thickness variability on interannual, basin-wide scales. When using this technique an assumption is made that the peak of the radar return originates from the snow/ice interface. This has been shown to be true in the laboratory for cold, dry snow as is the case on Arctic sea ice during winter. However, this assumption has not been tested in the field. We use data from an airborne normal-incidence Ku-band radar altimeter and in situ field measurements, collected during the CryoSat Validation Experiment (CryoVEx) Bay of Bothnia, 2006 and 2008 field campaigns, to determine the dominant scattering surface for Arctic snow-covered sea ice. In 2006, when the snow temperatures were close to freezing, the dominant scattering surface in 25% of the radar returns appeared closer to the snow/ice interface than the air/snow interface. However, in 2008, when temperatures were lower, the dominant scattering surface appeared closer to the snow/ice interface than the air/snow interface in 80% of the returns.
    Type of Medium: Online Resource
    ISSN: 0260-3055 , 1727-5644
    URL: Article
    DOI: 10.3189/172756411795931589
    Language: English
    Publisher: International Glaciological Society
    Publication Date: 2011
    detail.hit.zdb_id: 2122400-6
    SSG: 14
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    Online Resource
  • 3
    Online Resource
    Online Resource
    Using airborne Ku-band altimeter waveforms to investigate winter accumulation and glacier facies on Austfonna, Svalbard
    International Glaciological Society ; 2013
    In:  Journal of Glaciology Vol. 59, No. 217 ( 2013), p. 893-899
    Details
    In: Journal of Glaciology, International Glaciological Society, Vol. 59, No. 217 ( 2013), p. 893-899
    Abstract: Winter balance is an important metric for assessing the change on glaciers and ice caps, yet measuring it using ground-based techniques can be challenging. We use the European Space Agency prototype Airborne SAR/Interferometric Radar Altimeter System (ASIRAS) to extract snow depths from the received altimeter waveforms over Austfonna ice cap, Svalbard. Additionally, we attempt to distinguish the long-term firn area from other glacier facies. We validate our results using snow depth and glacier facies characterizations determined from ground-based radar profiles, snow pits and a multi-look satellite synthetic aperture radar image. We show that the depth of the winter snowpack can be extracted from the altimeter data over most of the accumulation zone, comprising wet snow zone and a superimposed ice zone. The method struggles at lower elevations where internal reflections within the winter snowpack are strong and the winter snow depth is less than ∼1 m. We use the abruptness of the reflection from the last summer surface (LSS) to attempt to distinguish glacier facies. While there is a general correlation between LSS abruptness and glacier facies, we do not find a relationship that warrants a distinct classification based on ASIRAS waveforms alone.
    Type of Medium: Online Resource
    ISSN: 0022-1430 , 1727-5652
    URL: Article
    DOI: 10.3189/2013JoG13J051
    Language: English
    Publisher: International Glaciological Society
    Publication Date: 2013
    detail.hit.zdb_id: 2140541-4
    SSG: 14
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    Online Resource
  • 4
    Online Resource
    Online Resource
    Characteristics and small-scale variability of GPR signals and their relation to snow accumulation in Greenland’s percolation zone
    International Glaciological Society ; 2008
    In:  Journal of Glaciology Vol. 54, No. 185 ( 2008), p. 333-342
    Details
    In: Journal of Glaciology, International Glaciological Society, Vol. 54, No. 185 ( 2008), p. 333-342
    Abstract: We investigate snowpack properties at a site in west-central Greenland with ground-penetrating radar (GPR), supplemented by stratigraphic records from snow pits and shallow firn cores. GPR data were collected at a validation test site for CryoSat (T05 on the Expéditions Glaciologiques Internationales au Groenland (EGIG) line) over a 100 m × 100 m grid and along 1 km sections at frequencies of 500 and 800 MHz. Several internal reflection horizons (IRHs) down to a depth of 10 m were tracked. IRHs are usually related to ice-layer clusters in vertically bounded sequences that obtain their initial characteristics near the surface during the melt season. Warm conditions in the following melt season can change these characteristics by percolating meltwater. In cold conditions, smaller melt volumes at the surface can lead to faint IRHs. The absence of simple mechanisms for internal layer origin emphasizes the need for independent dating to reliably interpret remotely sensed radar data. Our GPR-derived depth of the 2003 summer surface of 1.48 m (measured in 2004) is confirmed by snow-pit observations. The distribution of IRH depths on a 1 km scale reveals a gradient of increasing accumulation to the northeast of about 5 cm w.e. km −1 . We find that point measurements of accumulation in this area are representative only over several hundred metres, with uncertainties of about 15% of the spatial mean.
    Type of Medium: Online Resource
    ISSN: 0022-1430 , 1727-5652
    URL: Article
    DOI: 10.3189/002214308784886207
    Language: English
    Publisher: International Glaciological Society
    Publication Date: 2008
    detail.hit.zdb_id: 2140541-4
    SSG: 14
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    Online Resource
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...