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  • 1
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    PANGAEA
    In:  Supplement to: van Pelt, Ward; Pohjola, Veijo A; Pettersson, Rickard; Marchenko, Sergey; Kohler, Jack; Luks, Bartłomiej; Hagen, Jon Ove; Schuler, Thomas V; Dunse, Thorben; Noël, Brice P Y; Reijmer, Carleen H (2019): A long-term dataset of climatic mass balance, snow conditions, and runoff in Svalbard (1957-2018). The Cryosphere, 13(9), 2259-2280, https://doi.org/10.5194/tc-13-2259-2019
    Publication Date: 2023-01-30
    Description: The dataset contains model output presented in the manuscript 'A long-term dataset of climatic mass balance, snow conditions and runoff in Svalbard (1957-2018)', which is considered for publication in The Cryosphere. The data are structured in 3-D arrays containing spatially distributed and annual mean values of the variables specified below. The spatial resolution is 1x1-km. Variables included in the dataset: ----------------------------- - Climatic mass balance - Air temperature - Precipitation - Runoff - Refreezing - Pore space (down to 14 m) - Subsurface temperature (at 14 m depth) - Snow disappearance date - Snow onset date
    Keywords: File content; File format; File name; File size; glaciers; MULT; Multiple investigations; runoff; snow; Svalbard; Uniform resource locator/link to file
    Type: Dataset
    Format: text/tab-separated-values, 45 data points
    Location Call Number Limitation Availability
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  • 2
    Publication Date: 2024-04-20
    Description: Compared to other Arctic ice masses, Svalbard glaciers are low-elevated with flat interior accumulation areas, resulting in a marked peak in their current hypsometry (area-elevation distribution) at ~450 m above sea level. Since summer melt consistently exceeds winter snowfall, these low-lying glaciers can only survive by refreezing a considerable fraction of surface melt and rain in the porous firn layer covering their accumulation zones. We use a high-resolution climate model to show that modest atmospheric warming in the mid-1980s forced the firn zone to retreat upward by ~100 m to coincide with the hypsometry peak. This led to a rapid areal reduction of firn cover available for refreezing, and strongly increased runoff from dark, bare ice areas, amplifying mass loss from all elevations. As the firn line fluctuates around the hypsometry peak in the current climate, Svalbard glaciers will continue to lose mass and show high sensitivity to temperature perturbations. The data set includes annual cumulative SMB and components statistically downscaled from the output of the Regional Atmospheric Climate Model RACMO2.3 to 500 m spatial resolution (1958-2018). SMB components include total precipitation (snowfall and rainfall), snowfall, runoff, melt, refreezing and retention (mm w.e. per year), as well as summer (June-July-August) 2 m air temperature (K). The data set also includes modelled (RACMO2.3; 1958-2018) and observed (MODIS; 2000-2018) bare ice area, and modelled ablation zone area (1958-2018; km2). The mask file includes longitude/latitude (ºN/ºW), land-sea, ice and sector masks from the Randolph Glacier Inventory version 6, and surface topography (m above sea level) from the S0 Terreng Digital Elevation Model (Norwegian Polar Institute) on the 500 m grid. Daily downscaled SMB and components are available from the authors upon request and without conditions (b.p.y.noel@uu.nl).
    Keywords: Binary Object; Binary Object (File Size); Binary Object (Media Type); MULT; Multiple investigations; RACMO; SMB; Svalbard
    Type: Dataset
    Format: text/tab-separated-values, 11 data points
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  • 3
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    IASC
    In:  EPIC3IASC Workshop on the dynamics and mass budget of Arctic glaciers, Obergurgl, Austria, 2020-01-28-2020-01-30Obergurgl, Austria, IASC, 56 p.
    Publication Date: 2020-06-08
    Description: Kongsvegen is a well-studied surge-type glacier in the Kongsfjord area of northwest Svalbard. Long-term monitoring has shown that the ice surface velocity has been increasing for the past 4 years; presenting a unique opportunity to study the internal ice structure, basal conditions and thermal regime that play a crucial role in initiating glacier surges. In April 2019, three-component seismic vibroseis surveys were conducted at two sites on the glacier, using a small Electrodynamic Vibrator source (ElViS). Site 1 is in the ablation area and site 2 near the equilibrium line, where the greatest increase in ice surface velocity has been observed. Initial analysis indicates the conditions at the two sites are significantly different. At site 1 the ice is around 220 m thick, sitting on a relatively flat and uniform bed, with no clear change in the bed reflection along the profile. There is a horizontally layered sediment package ∼60 m thick underlaying the bed. The ice column shows no internal layering. By contrast at site 2 (Fig. 1), where the ice is around 390 m thick, there is much more complex internal ice structure. Clear internal ice reflections are visible between 150-250 m depth – where we expect a transition from cold to temperate ice. Further reflections in the 100 m above the bed indicate there could be shearing or sediment entrainment in this area. Below the bed, cross-cutting layers are clearly visible and the bed reflection itself shows changing reflection polarity – suggesting water or very wet sediment is present in some areas. This suggests ice movement by basal sliding and shearing is likely.
    Repository Name: EPIC Alfred Wegener Institut
    Type: Conference , notRev
    Format: application/pdf
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  • 4
    Publication Date: 2016-11-15
    Description: Ice shelves play an important role in stabilizing the interior grounded ice of the large ice sheets. The thinning of major ice shelves observed in recent years, possibly in connection to warmer ocean waters coming into contact with the ice-shelf base, has focused attention on the ice-ocean interface. Here we reveal a complex network of sub ice-shelf channels under the Fimbul Ice Shelf, Antarctica, mapped using ground-penetrating radar over a 100 km2 grid. The channels are 300–500 m wide and 50 m high, among the narrowest of any reported. Observing narrow channels beneath an ice shelf that is mainly surrounded by cold ocean waters, with temperatures close to the surface freezing point, shows that channelized basal melting is not restricted to rapidly melting ice shelves, indicating that spatial melt patterns around Antarctica are likely to vary on scales that are not yet incorporated in ice-ocean models.
    Repository Name: EPIC Alfred Wegener Institut
    Type: Article , isiRev
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  • 5
    Publication Date: 2017-10-17
    Description: 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 1m. 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.
    Repository Name: EPIC Alfred Wegener Institut
    Type: Article , isiRev
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  • 6
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    COPERNICUS GESELLSCHAFT MBH
    In:  EPIC3The Cryosphere, COPERNICUS GESELLSCHAFT MBH, 10(2), pp. 751-760, ISSN: 1994-0424
    Publication Date: 2016-04-11
    Description: As ice flows over a subglacial lake, the drop in bed resistance leads to an increase in ice velocities and a draw down of isochrones and cold ice. The ice surface flattens as it adjusts to the lack of resisting forces at the base. The rapid transition in velocity induces changes in ice viscosity and releases deformation energy that can raise the temperature locally. Recent studies of Antarctic subglacial lakes indicate that many lakes experience very fast and possibly episodic drainage, during which the lake size is rapidly reduced as water flows out. Questions that arise are what effect this would have on internal layers within the ice and whether such past drainage events could be inferred from isochrone structures downstream. Here, we study the effect of a subglacial lake on ice dynamics as well as the influence that such short timescale drainage would have on the internal layers of the ice. To this end, we use a full Stokes, polythermal ice flow model. An enthalpy-gradient method is used to account for the evolution of temperature and water content within the ice. We find that a rapid transition between slow-moving ice outside the lake, and full sliding over the lake, can release considerable amounts of deformational energy, with the potential to form a temperate layer at depth in the transition zone. In addition, we provide an explanation for a characteristic surface feature commonly seen at the edges of subglacial lakes, a hummocky surface depression in the transition zone between little to full sliding. We also conclude that rapid changes in the horizontal extent of subglacial lakes and slippery patches, compared to the average ice column velocity, can create a traveling wave at depth within the isochrone structure that transfers downstream with the advection of ice, thus indicating the possibility of detecting past drainage events with ice penetrating radar.
    Repository Name: EPIC Alfred Wegener Institut
    Type: Article , isiRev
    Format: application/pdf
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  • 7
    Publication Date: 2024-01-11
    Description: One of the key components of this research has been the mapping of Antarctic bed topography and ice thickness parameters that are crucial for modelling ice flow and hence for predicting future ice loss and the ensuing sea level rise. Supported by the Scientific Committee on Antarctic Research (SCAR), the Bedmap3 Action Group aims not only to produce new gridded maps of ice thickness and bed topography for the international scientific community, but also to standardize and make available all the geophysical survey data points used in producing the Bedmap gridded products. Here, we document the survey data used in the latest iteration, Bedmap3, incorporating and adding to all of the datasets previously used for Bedmap1 and Bedmap2, including ice bed, surface and thickness point data from all Antarctic geophysical campaigns since the 1950s. More specifically, we describe the processes used to standardize and make these and future surveys and gridded datasets accessible under the Findable, Accessible, Interoperable, and Reusable (FAIR) data principles. With the goals of making the gridding process reproducible and allowing scientists to re-use the data freely for their own analysis, we introduce the new SCAR Bedmap Data Portal (https://bedmap.scar.org, last access: 1 March 2023) created to provide unprecedented open access to these important datasets through a web-map interface. We believe that this data release will be a valuable asset to Antarctic research and will greatly extend the life cycle of the data held within it. Data are available from the UK Polar Data Centre: https://data.bas.ac.uk (last access: 5 May 2023​​​​​​​). See the Data availability section for the complete list of datasets.
    Description: Published
    Description: 2695–2710
    Description: OSA2: Evoluzione climatica: effetti e loro mitigazione
    Description: JCR Journal
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
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  • 8
    Publication Date: 2024-01-18
    Description: One of the key components of this research has been the mapping of Antarctic bed topography and ice thickness parameters that are crucial for modelling ice flow and hence for predicting future ice loss and the ensuing sea level rise. Supported by the Scientific Committee on Antarctic Research (SCAR), the Bedmap3 Action Group aims not only to produce new gridded maps of ice thickness and bed topography for the international scientific community, but also to standardize and make available all the geophysical survey data points used in producing the Bedmap gridded products. Here, we document the survey data used in the latest iteration, Bedmap3, incorporating and adding to all of the datasets previously used for Bedmap1 and Bedmap2, including ice bed, surface and thickness point data from all Antarctic geophysical campaigns since the 1950s. More specifically, we describe the processes used to standardize and make these and future surveys and gridded datasets accessible under the Findable, Accessible, Interoperable, and Reusable (FAIR) data principles. With the goals of making the gridding process reproducible and allowing scientists to re-use the data freely for their own analysis, we introduce the new SCAR Bedmap Data Portal (https://bedmap.scar.org, last access: 1 March 2023) created to provide unprecedented open access to these important datasets through a web-map interface. We believe that this data release will be a valuable asset to Antarctic research and will greatly extend the life cycle of the data held within it. Data are available from the UK Polar Data Centre: https://data.bas.ac.uk (last access: 5 May 2023). See the Data availability section for the complete list of datasets.
    Repository Name: EPIC Alfred Wegener Institut
    Type: Article , isiRev
    Format: application/pdf
    Location Call Number Limitation Availability
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  • 9
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Polar research 22 (2003), S. 0 
    ISSN: 1751-8369
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Geography , Geosciences
    Notes: Gain or loss of the freshwater stored in Svalbard glaciers has both global implications for sea level and, on a more local scale, impacts upon the hydrology of rivers and the freshwater flux to fjords. This paper gives an overview of the potential runoff from the Svalbard glaciers. The freshwater flux from basins of different scales is quantified. In small basins (A 〈 10 km2), the extra runoff due to the negative mass balance of the glaciers is related to the proportion of glacier cover and can at present yield more than 20% higher runoff than if the glaciers were in equilibrium with the present climate. This does not apply generally to the ice masses of Svalbard, which are mostly much closer to being in balance. The total surface runoff from Svalbard glaciers due to melting of snow and ice is roughly 25 ± 5 km3 a−1, which corresponds to a specific runoff of 680 ± 140 mm a−1, only slightly more than the annual snow accumulation. Calving of icebergs from Svalbard glaciers currently contributes significantly to the freshwater flux and is estimated to be 4 ± 1 km3 a−1 or about 110 mm a−1.
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    [s.l.] : Nature Publishing Group
    Nature 445 (2007), S. 830-831 
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] Antarctica is well known as the coldest place on Earth, but it is also surprisingly wet. Whereas the upper part of the ice is cold, geothermal heat and the insulating effect of the overlying ice combine towards its base to bring extensive areas of ice at the bed to its melting point. In the most ...
    Type of Medium: Electronic Resource
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