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  • 1.
    Fransson, Agneta
    et al.
    Norwegian Polar Res Inst, Fram Ctr, Tromso, Norway.;Univ Gothenburg, Dept Earth Sci, Gothenburg, Sweden..
    Chierici, Melissa
    Univ Gothenburg, Dept Chem & Mol Biol, Gothenburg, Sweden.;Inst Marine Res, Tromso, Norway..
    Abrahamsson, Katarina
    Univ Gothenburg, Dept Chem & Mol Biol, Gothenburg, Sweden..
    Andersson, Maria
    Univ Gothenburg, Dept Chem & Mol Biol, Gothenburg, Sweden..
    Granfors, Anna
    Univ Gothenburg, Dept Chem & Mol Biol, Gothenburg, Sweden..
    Gårdfeldt, Katarina
    Univ Gothenburg, Chalmers Univ Technol, Ctr Environm & Sustainabil, Gothenburg, Sweden..
    Torstensson, Anders
    Univ Gothenburg, Dept Biol & Environm Sci, Gothenburg, Sweden..
    Wulff, Angela
    Univ Gothenburg, Dept Biol & Environm Sci, Gothenburg, Sweden..
    CO2-system development in young sea ice and CO2 gas exchange at the ice/air interface mediated by brine and frost flowers in Kongsfjorden, Spitsbergen2015Ingår i: Annals of Glaciology, ISSN 0260-3055, E-ISSN 1727-5644, Vol. 56, nr 69, s. 245-257Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In March and April 2010, we investigated the development of young landfast sea ice in Kongsfjorden, Spitsbergen, Svalbard. We sampled the vertical column, including sea ice, brine, frost flowers and sea water, to determine the CO2 system, nutrients, salinity and bacterial and ice algae production during a 13 day interval of ice growth. Apart from the changes due to salinity and brine rejection, the sea-ice concentrations of total inorganic carbon (C-T), total alkalinity (A(T)), CO2 and carbonate ions (CO32-) in melted ice were influenced by dissolution of calcium carbonate (CaCO3) precipitates (25-55 mu mol kg(-1)) and played the largest role in the changes to the CO2 system. The C-T values were also influenced by CO2 gas flux, bacterial carbon production and primary production, which had a small impact on the C-T. The only exception was the uppermost ice layer. In the top 0.05 m of the ice, there was a CO2 loss of similar to 20 mu mol kg(-1) melted ice (1 mmol m(-2)) from the ice to the atmosphere. Frost flowers on newly formed sea ice were important in promoting ice-air CO2 gas flux, causing a CO2 loss to the atmosphere of 140-800 mu mol kg(-1) d(-1) melted frost flowers (7-40 mmol m(-2)d(-1)).

  • 2. Gude, Martin
    et al.
    Scherer, Dieter
    Snowmelt and slushflows: Hydrological and hazard implications1998Ingår i: Annals of Glaciology, ISSN 0260-3055, E-ISSN 1727-5644, Vol. 26, s. 381-384Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In many high-latitude areas, slushflows occur frequently during the snowmelt period but information on the initiation mechanism is rare. Field observations and measurements of slushflows in northwestern Spitsbergen and in northern Sweden demonstrate the role of meltwater accumulation and the hydraulic pressure gradient in the release process. Snow metamorphism is revealed to be of minor importance in the observed events. The monitoring of water-pressure development in a saturated snow cover demonstrates that preferred release areas are within low-gradient valley sections, where meltwater inflow is higher than outflow. Slushflows consist of mudflow-like flowage of water-saturated snow along stream courses. They represent transitional processes between fluvial floods and avalanches. On the other hand, they possess unique characteristics concerning release and movement. The comparative evaluation of definition items for fluvial floods, slushflows and avalanches offers hasic data suitable for a risk assessment.

  • 3.
    Hedfors, Jim
    et al.
    Uppsala universitet, Miljö- och landskapsdynamik.
    Pohjola, Veijo
    Uppsala universitet, Miljö- och landskapsdynamik.
    Ice flux of Plogbreen, a small ice stream in Dronning Maud Land, Antarctica2004Ingår i: Annals of Glaciology, ISSN 0260-3055, E-ISSN 1727-5644, Vol. 39, nr 1, s. 409-416Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    As part of a long-term mass-balance program run by SWEDARP since 1988, a detailed study on Plogbreen, Dronning Maud Land, Antarctica, was undertaken during the austral summer of 2003 to investigate the long-term mass balance. We compare ice outflux, φout, through a cross-sectional gate with ice influx, φin, from the upstream catchment area. The φin is based on calculations of snow accumulation upstream of the gate using data available from published ice-core records. The φout is based on Glen's flow law aided by thermodynamic modeling and force-budget calculations. Input data from the field consist of measurements of ice surface velocity and ice geometry. The ice surface velocity was measured using repeated differential global positioning system surveying of 40 stakes over a period of 25 days. The ice geometry was determined by 174 km of ground-penetrating radar profiling using ground-based 8 MHz dipole antennas. This study presents the collected velocity and geometry data as well as the calculated ice flux of Plogbreen. The results show a negatively balanced system within the uncertainty limits; φout = 0.55 ± 0.05 km3 a−1 and φin = 0.4 ± 0.1 km3 a−1. We speculate that the negative balance can be explained by recent eustatic increase reducing resistive stresses and inducing accelerated flow.

  • 4. Isaksson, Elisabeth
    et al.
    van den Broeke, Michiel R.
    Winther, Jan-Gunnar
    Karlöf, Lars
    Francis Pinglot, Jean
    Gundestrup, Niels
    Accumulation and proxy-temperature variability in Dronning Maud Land, Antarctica, determined from shallow firn cores1999Ingår i: Annals of Glaciology, ISSN 0260-3055, E-ISSN 1727-5644, Vol. 29, s. 17-22Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    During 1996-97 a European Project for Ice Coring in Antarctica (EPICA) pre-site surveying traverse worked in the area between 70° S, 5° E and 75° S, 15° E in Dronning Maud Land. We present data obtained from 10 and 20 m deep firn cores drilled between the coast and 600 km inland (to 3450 m a.s.l.). The cores were analyzed for electrical conductivity measurements and total β activity to obtain accumulation data between known time horizons. In addition, some of the cores were analyzed for oxygen isotopes. Annual accumulation varies from 271 mm we. at Fimbulisen to 24 mm we at 2840 m a.s.l. Accumulation at core sites 2400-3000 m a.s.l. has increased by 16-48% since 1965 compared to the 1955-65 period. However, the core sites above 3250 m a.s.l. and one core location on the ice shelf show a decrease during the same period. Furthermore, no change can be detected at the most inland site for the period 1815-1996. In all the cores the last few years seem to have been some of the warmest in these records.

  • 5.
    Pohjola, Veijo A
    et al.
    Uppsala universitet, Luft-, vatten och landskapslära.
    Hedfors, Jim
    Uppsala universitet, Miljö- och landskapsdynamik.
    Holmlund, Per
    Investigating the potential to determine the upstream accumulation rate, using mass flux calculations along a cross-section on a small tributary glacier in Heimefrontfjella, Dronning Maud Land, Antarctica2004Ingår i: Annals of Glaciology, ISSN 0260-3055, E-ISSN 1727-5644, Vol. 39, nr 1, s. 175-180Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    How well can we estimate the incoming ice flux by calculating the ice flux through a well-defined cross-section? We test this by comparing calculated ice flux out from the small glacier Bonnevie-Svendsenbreen with the measured accumulation rate integrated over the well-defined catchment area in the Sivorgfjella plateau, Dronning Maud Land, Antarctica (74°45′S, 11°10′W). The ice flux is calculated using ice-dynamical properties from an ice temperature model and the distribution of forces calculated using a force-budget model. The input we use includes velocity data of the glacier surface, combined with ice-thickness measurements. The result is an accumulation rate on the Sivorgfjella plateau of 0.50 ± 0.05 m w.e.a−1. We find that this is similar to the accumulation rate recorded by ground-penetrating radar work in the area. We therefore find the balance-flow method, in combination with the force-budget technique and ice temperature modeling, to be a useful tool for studies of mass fluxes in a catchment area. The most important source of uncertainty in these calculations is the quality and the spatial distribution of the ice surface velocity data. The high accumulation rate shows the effect of orographic enhancement on accumulation in montane areas in Antarctica.

  • 6. Sinisalo, Anna
    et al.
    Moore, John C.
    Van De Wal, Roderik S.W.
    Bintanja, Richard
    Jonsson, Stig
    A 14 year mass-balance record of a blue-ice area in Antarctica2003Ingår i: Annals of Glaciology, ISSN 0260-3055, E-ISSN 1727-5644, Vol. 37, s. 213-218Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Accumulation and ablation rates over an Antarctic blue-ice area spanning the 14year period 1988–2002 are presented. Data were obtained by direct stake measurements. Large spatial and temporal variations in the net balance were observed without any clear trend over the entire period. There are marginally significant increases in snow accumulation, and in ablation in the blue-ice area farthest from the equilibrium zone (both at the 95% confidence level). The snow/blue-ice transition zone shows no change over the entire period of observation,and the blue-ice area near the zone shows no change in ablation rate over the 14 year period. The mass-balance gradient in Scharffenbergbotnen may have increased during the period 1988–2002. However, the changes are small, especially when compared with the changes observed elsewhere in Antarctica even relatively close to the blue-ice area. This may indicate that the blue-ice areas are relatively stable to changes in accumulation rate, and possibly temperature.

  • 7. Sugiyama, S.
    et al.
    Enomoto, H.
    Fujita, S.
    Fukui, K.
    Nakazawa, F.
    Holmlund, P.
    Dielectric permittivity of snow measured along the route traversed in the Japanese-Swedish Antarctic Expedition 2007/082010Ingår i: Annals of Glaciology, ISSN 0260-3055, E-ISSN 1727-5644, Vol. 51Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    As a joint contribution of Japan and Sweden to the International Polar Year 2007-09, a field expedition between Syowa and Wasa stations in East Antarctica was carried out in the 2007/08 austral summer season. Along the 2800 km long expedition route, the dielectric permittivity of the upper 1 m snow layer was measured at intervals of approximately 50 km using a snow fork, a parallel-wire transmission-line resonator. More than 2000 measurements were performed under carefully calibrated conditions, mostly in the interior of Antarctica. The permittivity epsilon' was a function of snow density as in previous studies on dry snow, but the values were significantly smaller than those reported before. In the light of the dielectric mixture theory, the relatively smaller e' obtained in this study can be attributed to the snow structures characteristic in the studied region. Our data suggest that the permittivity of snow in the Antarctic interior is significantly affected by weak bonding between snow grains, which is due to depth-hoar formation in the extremely low-temperature conditions.

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