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  • 1
    Electronic Resource
    Electronic Resource
    Snow research in Svalbard–an overview (2003)
    Oxford, UK : Blackwell Publishing Ltd
    Polar research 22 (2003), S. 0 
    Details
    ISSN: 1751-8369
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Geography , Geosciences
    Notes: This paper summarizes the most significant snow-related research that has been conducted in Svalbard. Most of the research has been performed during the 1990s and includes investigations of snow distribution, snow-melt, snow pack characteristics, remote sensing of snow and biological studies where snow conditions play an important role. For example, studies have shown regional trends with about 50% higher amounts of snow accumulation at the east coast of Spitsbergen compared to the west coast. Further, the accumulation rates are about twice as high in the south compared to the north. On average, the increase in accumulation with elevation is 97 mm water equivalents per 100 m increase in elevation. Several researchers reported melt rates, which are primarily driven by incoming short-wave radiation, in the range of 10-20 mm/day during spring. Maximum melt rates close to 70 mm/day have been measured. In addition to presenting an overview of research activities, we discuss new, unpublished results in areas where considerable progress is being made. These are i) modelling of snow distribution, ii) modelling of snowmelt runoff and iii) monitoring of snow coverage by satellite imagery. We also identify some weaknesses in current research activities. They are lacks of i) integration between various studies, ii) comparative studies with other Arctic regions, iii) applying local field studies in models that can be used to study larger areas of Svalbard and, finally, iv) using satellite remote sensing data for operational monitoring purposes.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1751-8369.2003.tb00103.x
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  • 2
    Electronic Resource
    Electronic Resource
    Surface reflectance of sea ice and under-ice irradiance in Kongsfjorden, Svalbard (2004)
    Oxford, UK : Blackwell Publishing Ltd
    Polar research 23 (2004), S. 0 
    Details
    ISSN: 1751-8369
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Geography , Geosciences
    Notes: Initial results from a field experiment on fast ice in Kongsfjorden, Svalbard, in March 2002 are presented. We measured surface reflectance and under-ice irradiance using an advanced, portable spectroradiometer sensitive in the visible and near-infrared parts of the electromagnetic spectrum, i.e. 350-1100 nm. Under-ice irradiance (UV-A, UV-B and photosynthetically active radiation [PAR]) was measured down to depths of 7.5 m by vertical profiling using a six-channel radiometer. We also present model results of wavelength-dependent transmittance of radiation through a combined snow and sea ice layer for various thicknesses of snow. Model results show that the snow and sea ice is more transparent for solar radiation in the PAR region (400-700 nm) than at shorter and longer wavelengths. This is confirmed by the field measurements. Even very thin snow layers on top of the sea ice efficiently prevent solar radiation from penetrating the snow–sea ice system. For example, a 5 cm thick snow layer reduces under-ice irradiance in the PAR region with a factor of about 10. Measurements of under-ice UV irradiance show that both UV-A and UV-B irradiance is reduced with a factor of more than 10 at depths of 7.5 m below the ice compared to at the ice-sea water interface.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1751-8369.2004.tb00134.x
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  • 3
    Electronic Resource
    Electronic Resource
    The physical environment of Kongsfjorden–Krossfjorden, an Arctic fjord system in Svalbard (2002)
    Oxford, UK : Blackwell Publishing Ltd
    Polar research 21 (2002), S. 0 
    Details
    ISSN: 1751-8369
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Geography , Geosciences
    Notes: Kongsfjorden-Krossfjorden and the adjacent West Spitsbergen Shelf meet at the common mouth of the two fjord arms. This paper presents our most up-to-date information about the physical environment of this fjord system and identifies important gaps in knowledge. Particular attention is given to the steep physical gradients along the main fjord axis, as well as to seasonal environmental changes. Physical processes on different scales control the large-scale circulation and small-scale (irreversible) mixing of water and its constituents. It is shown that, in addition to the tide, run-off (glacier ablation, snowmelt, summer rainfall and ice calving) and local winds are the main driving forces acting on the upper water masses in the fjord system. The tide is dominated by the semi-diurnal component and the freshwater supply shows a marked seasonal variation pattern and also varies interannually. The wind conditions are characterized by prevailing katabatic winds, which at times are strengthened by the geostrophic wind field over Svalbard. Rotational dynamics have a considerable influence on the circulation patterns within the fjord system and give rise to a strong interaction between the fjord arms. Such dynamics are also the main reason why variations in the shelf water density field, caused by remote forces (tide and coastal winds), propagate as a Kelvin wave into the fjord system. This exchange affects mainly the intermediate and deep water, which is also affected by vertical convection processes driven by cooling of the surface and brine release during ice formation in the inner reaches of the fjord arms. Further aspects covered by this paper include the geological and geomorphological characteristics of the Kongsfjorden area, climate and meteorology, the influence of glaciers, freshwater supply, sea ice conditions, sedimentation processes as well as underwater radiation conditions. The fjord system is assumed to be vulnerable to possible climate changes, and thus is very suitable as a site for the demonstration and investigation of phenomena related to climate change.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1751-8369.2002.tb00072.x
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  • 4
    Electronic Resource
    Electronic Resource
    Physical properties, spectral reflectance and thickness development of first year fast ice in Kongsfjorden, Svalbard (1999)
    Oxford, UK : Blackwell Publishing Ltd
    Polar research 18 (1999), S. 0 
    Details
    ISSN: 1751-8369
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Geography , Geosciences
    Notes: A ground truth study was performed on first year fast ice in Kongsfjorden, Svalbard, during spring 1997 and 1998. The survey included sea ice thickness monitoring as well as observation of surface albedo, attenuation of optical radiation in the ice, physical properties and texture of snow and sea ice. The average total sea ice thickness in May was about 0.9 m, including a 0.2 m thick snow layer on top. Within a few weeks in both years, the snow melted almost completely, whereas the ice thickness decreased by not more than 0.05 m. During spring, the lower part of the snow refroze into a solid layer. The sea ice became more porous. Temperatures in the sea ice increased and the measurable salinity of the sea ice decreased with time. Due to snow cover thinning and snow grain growth, maximum surface albedo decreased from 0.96 to 0.74. Texture analysis on cores showed columnar ice with large crystals (max. crystal lenght 〉 0.1 m) below a 0.11 m thick mixed surface layer of granular ice with smaller crystals. In both years, we observed sea ice algae at the bottom part of the ice. This layer has a significant effect on the radiation transmissivity.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1751-8369.1999.tb00304.x
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  • 5
    Electronic Resource
    Electronic Resource
    Nondestructive density determination on marine sediment cores from gamma-ray attenuation measurements (1995)
    Springer
    Geo-marine letters 15 (1995), S. 111-118 
    Details
    ISSN: 1432-1157
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences
    Notes: Abstract We describe an improved nondestructive technique for density measurement based on gamma-ray absorption that permits construction of high-resolution density profiles of marine sediment cores. The system is capable of resolving vertical density variations with a spatial resolution of 4 mm and absolute accuracy of ± 1%. Comparison with conventional density determination on samples confirms the absolute accuracy. In addition to standard vertical profiling, a core rotation option is included to measure density as a function of rotation angle. This allows the quantification of the variability of density within a layer and detection of inhomogenities like icerafted debris or biogenic structures.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01275415
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    Paper (German National Licenses)
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