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  • 1.
    Beaudon, Emilie
    et al.
    Univ Lapland, Arctic Ctr, Rovaniemi 96101, Finland..
    Arppe, Laura
    Univ Helsinki, Dept Geosci & Geog, FIN-00014 Helsinki, Finland..
    Jonsell, Ulf
    Univ Politecn Madrid, ETSI Telecomun, City Univ, E-28040 Madrid, Spain.;Uppsala Univ, Dept Earth Sci, S-75236 Uppsala, Sweden..
    Martma, Tonu
    Tallinn Univ Technol, Inst Geol, EE-19086 Tallinn, Estonia..
    Moeller, Marco
    Rhein Westfal TH Aachen, Dept Geog, D-52056 Aachen, Germany..
    Pohjola, Veijo A.
    Uppsala Univ, Dept Earth Sci, S-75236 Uppsala, Sweden..
    Scherer, Dieter
    Tech Univ Berlin, Dept Ecol, D-12165 Berlin, Germany..
    Moore, John C.
    Univ Lapland, Arctic Ctr, Rovaniemi 96101, Finland.;Beijing Normal Univ, Coll Global Change, Beijing 100875, Peoples R China.;Beijing Normal Univ, Coll Earth Syst Sci, Beijing 100875, Peoples R China..
    SPATIAL AND TEMPORAL VARIABILITY OF NET ACCUMULATION FROM SHALLOW CORES FROM VESTFONNA ICE CAP (NORDAUSTLANDET, SVALBARD)2011In: Geografiska Annaler. Series A, Physical Geography, ISSN 0435-3676, E-ISSN 1468-0459, Vol. 93A, no 4, p. 287-299Article in journal (Refereed)
    Abstract [en]

    We analyse ice cores from Vestfonna ice cap (Nordaustlandet, Svalbard). Oxygen isotopic measurements were made on three firn cores (6.0, 11.0 and 15.5 m deep) from the two highest summits of the glacier located on the SWNE and NWSE central ridges. Sub-annual d18O cycles were preserved and could be counted visually in the uppermost parts of the cores, but deeper layers were affected by post-depositional smoothing. A pronounced d18O minimum was found near the bottom of the three cores. We consider candidates for this d18O signal to be a valuable reference horizon since it is also seen elsewhere in Nordaustlandet. We attribute it to isotopically depleted snow precipitation, which NCEP/NCAR reanalysis shows was unusual for Vestfonna, and came from northerly air during the cold winter of 1994/95. Finding the 1994/95 time marker allows establishment of a precise depth/age scale for the three cores. The derived annual accumulation rates indirectly fill a geographical gap in mass balance measurements and thus provide information on spatial and temporal variability of precipitation over the glacier for the period spanned by the cores (19922009). Comparing records at the two locations also reveals that the snow net accumulation at the easternmost part of Vestfonna was only half of that in the western part over the last 17 years.

  • 2.
    Beaudon, Emilie
    et al.
    Univ Lapland, Arctic Ctr, Rovaniemi, Finland..
    Moore, John C.
    Univ Lapland, Arctic Ctr, Rovaniemi, Finland.;Beijing Normal Univ, Coll Global Change & Earth Syst Sci, Beijing 100875, Peoples R China.;Uppsala Univ, Dept Earth Sci, Uppsala, Sweden..
    Martma, Tonu
    Tallinn Univ Technol, Inst Geol, EE-19086 Tallinn, Estonia..
    Pohjola, Veijo A.
    Uppsala Univ, Dept Earth Sci, Uppsala, Sweden..
    van de Wal, Roderik S. W.
    Univ Utrecht, Inst Marine & Atmospher Res Utrecht, Utrecht, Netherlands..
    Kohler, Jack
    Fram Ctr, Norwegian Polar Inst, Tromso, Norway..
    Isaksson, Elisabeth
    Fram Ctr, Norwegian Polar Inst, Tromso, Norway..
    Lomonosovfonna and Holtedahlfonna ice cores reveal east west disparities of the Spitsbergen environment since AD 17002013In: Journal of Glaciology, ISSN 0022-1430, E-ISSN 1727-5652, Vol. 59, no 218, p. 1069-1083Article in journal (Refereed)
    Abstract [en]

    An ice core extracted from Holtedahlfonna ice cap, western Spitsbergen, record spanning the period 1700-2005, was analyzed for major ions. The leading empirical orthogonal function (EOF) component is correlated with an index of summer melt (log([Na+]/[Mg2-]) from 1850 and shows that almost 50% of the variance can be attributed to seasonal melting since the beginning of the industrial revolution. The Holtedahlfonna delta O-18 value is less negative than in the more easterly Lomonosovfonna ice core, suggesting that moist air masses originate from a closer source, most likely the Greenland Sea. During the Little Ice Age the lower methanesulfonic acid (MSA) concentration and MSA non-sea-salt sulfate fraction are consistent with the Greenland Sea as the main source for biogenic ions in the ice cores. Both the melt index and the MSA fraction suggest that the early decades of the 18th century may have exhibited the coldest summers of the last 300 years in Svalbard. Ammonium concentrations rise from 1880, which may result from the warming of the Greenland Sea or from zonal differences in atmospheric pollution transport over Svalbard. During winter, neutralized aerosols are trapped within the tropospheric inversion layer, which is usually weaker over open seas than over sea ice, placing Holtedahlfonna within the inversion more frequently than Lomonosovfonna.

  • 3.
    Divine, Dmitry
    et al.
    Norwegian Polar Res Inst, Fram Ctr, NO-9296 Tromso, Norway.;Univ Tromso, Fac Sci & Technol, Dept Math & Stat, NO-9037 Tromso, Norway..
    Isaksson, Elisabeth
    Norwegian Polar Res Inst, Fram Ctr, NO-9296 Tromso, Norway..
    Martma, Tonu
    Tallinn Univ Technol, Inst Geol, EE-19086 Tallinn, Estonia..
    Meijer, Harro A. J.
    Univ Groningen, Ctr Isotope Res, NL-9747 AG Groningen, Netherlands..
    Moore, John
    Univ Lapland, Arctic Ctr, FI-96101 Rovaniemi, Finland..
    Pohjola, Veijo
    Uppsala Univ, Dept Earth Sci, SE-75236 Uppsala, Sweden..
    van de Wal, Roderik S. W.
    Univ Utrecht, Inst Marine & Atmospher Res Utrecht, NL-3584 CC Utrecht, Netherlands..
    Godtliebsen, Fred
    Univ Tromso, Fac Sci & Technol, Dept Math & Stat, NO-9037 Tromso, Norway..
    Thousand years of winter surface air temperature variations in Svalbard and northern Norway reconstructed from ice-core data2011In: Polar Research, ISSN 0800-0395, E-ISSN 1751-8369, Vol. 30, article id 7379Article in journal (Refereed)
    Abstract [en]

    Two isotopic ice core records from western Svalbard are calibrated to reconstruct more than 1000 years of past winter surface air temperature variations in Longyearbyen, Svalbard, and Vardo, northern Norway. Analysis of the derived reconstructions suggests that the climate evolution of the last millennium in these study areas comprises three major sub-periods. The cooling stage in Svalbard (ca. 800-1800) is characterized by a progressive winter cooling of approximately 0.9 degrees C century(-1) (0.38 degrees C century(-1) for Vardo) and a lack of distinct signs of abrupt climate transitions. This makes it difficult to associate the onset of the Little Ice Age in Svalbard with any particular time period. During the 1800s, which according to our results was the coldest century in Svalbard, the winter cooling associated with the Little Ice Age was on the order of 4 degrees C (1.3 degrees C for Vardo) compared to the 1900s. The rapid warming that commenced at the beginning of the 20th century was accompanied by a parallel decline in sea-ice extent in the study area. However, both the reconstructed winter temperatures as well as indirect indicators of summer temperatures suggest the Medieval period before the 1200s was at least as warm as at the end of the 1990s in Svalbard.

  • 4. Isaksson, E
    et al.
    Hermanson, M
    Sheila, H C
    Igarashi, M
    Kamiyama, K
    Moore, J
    Motoyama, H
    Muir, D
    Pohjola, V
    Vaikmae, R
    van de Wal, R S W
    Watanabe, O
    Ice cores from Svalbard - useful archives of past climate and pollution history2003In: Physics and Chemistry of the Earth, ISSN 1474-7065, E-ISSN 1873-5193, Vol. 28, no 28-32, p. 1217-1228Article in journal (Refereed)
    Abstract [en]

    Ice cores from the relatively low-lying ice caps in Svalbard have not been widely exploited in climatic and environmental studies due to uncertainties about the effect of melt water percolation. However, results from two recent Svalbard ice cores, at Lomonosovfonna (1250 m asl) and Austfonna (750 m asl), have shown that with careful site selection, high-resolution sampling and multiple chemical analyses, it is possible to recover ice cores with partly preserved annual signals. These cores are estimated to cover at least the past 600 years and have been dated using a combination of known reference horizons and glacial modeling. The delta(18)O data from both Lomonosovfonna and Austfonna ice cores suggest that the 20th century was the warmest during the past 600 years. A comparison of the ice core and sea ice records from this period suggests that sea ice extent and Austfonna delta(18)O are linked over the past 400 years. This may reflect the position of the storm tracks and their direct influence on the relatively low altitude Austfonna. Lomonosovfonna may be less sensitive to such changes and primarily record atmospheric changes due to its higher elevation. The anthropogenic influence on Svalbard environment is illustrated by increased levels of non-sea-salt sulphate, nitrate, acidity, fly-ash and organic contaminants particularly during the second half of 1900s. Decreased concentrations of some components in recent decades most likely reflect emission and use restrictions. However, some current-use organic pesticide compounds show growing concentrations in near surface layers. (C) 2003 Elsevier Ltd. All rights reserved.

  • 5. Isaksson, E
    et al.
    Kohler, J
    Pohjola, V
    Moore, J
    Igarashi, M
    Karlof, L
    Martma, T
    Meijer, H
    Motoyama, H
    Vaikmae, R
    van de Wal, R S W
    Two ice-core delta O-18 records from Svalbard illustrating climate and sea-ice variability over the last 400 years2005In: The Holocene, ISSN 0959-6836, E-ISSN 1477-0911, Vol. 15, no 4, p. 501-509Article in journal (Refereed)
    Abstract [en]

    Ice cores from the relatively low-lying ice caps in Svalbard have not been widely exploited in climatic studies owing to uncertainties about the effect of meltwater percolation. However, results from two new Svalbard ice cores, at Lomonosovfonna and Austfonna, have shown that with careful site selection, high-resolution sampling and multiple chemical analyses it is possible to recover ice cores from which part of the annual signals are preserved, despite the considerable meltwater percolation. The new Svalbard ice cores are positioned in different parts of Svalbard and cover the past 800 years. In this paper we focus on the last 400 years. The delta O-18 signals from the cores are qualitatively similar over most of the twentieth century, suggesting that they record the same atmospheric signal. Prior to AD 1920, the Austfonna ice core exhibits more negative delta O-18 values than Lomonosovfonna, although there are intermittent decadal-scale periods throughout the record with similar values. We suggest that the differences reflect the effect of the inversion layer during the winter. The pattern in the delta O-18 records is similar to the Longyearbyen air-temperature record, but on an annual level the correlation is low. The Austforma record correlates well with the temperature record from the more distant and southwesterly located Jan Mayen. A comparison of the ice-core and sea-ice records from this period suggests that sea-ice extent and Austforma delta O-18 are related over the past 400 years. This may reflect the position of the storm tracks and their direct influence on the relatively low-altitude Austfonna. Lomonosovfonna may be less sensitive to such changes and primarily record free atmospheric changes instead of variations in sea-ice extent, the latter is probably a result of its higher elevation.

  • 6. Isaksson, E
    et al.
    Pohjola, V
    Jauhiainen, T
    Moore, J
    Pinglot, J M
    Vaikmae, R
    van de Wal, R S W
    Hagen, J O
    Ivask, J
    Karlof, L
    Martma, T
    Meijer, H A J
    Mulvaney, R
    Thomassen, M
    van den Broeke, M
    A new ice-core record from Lomonosovfonna, Svalbard: viewing the 1920-97 data in relation to present climate and environmental conditions2001In: Journal of Glaciology, ISSN 0022-1430, E-ISSN 1727-5652, Vol. 47, no 157, p. 335-345Article in journal (Refereed)
    Abstract [en]

    In 1997 a 121 m ice core was retrieved from Lomonosovfonna, the highest ice field in Spitsbergen, Svalbard (1250 m a.s.l.). Radar measurements indicate an ice depth of 126.5 m, and borehole temperature measurements show that the ice is below the melting point, High-resolution sampling of major ions, oxygen isotopes and deuterium has been performed on the core, and the results from the uppermost 36 rn suggest that quasi-annual signals are preserved. The 1963 radioactive layer is situated at 18.5-18.95 m, giving a mean annual accumulation of 0.36 m we. for the period 1963-96. The upper 36 rn of the ice core was dated back to 1920 by counting layers provided by the seasonal variations of the ions in addition to using a constant accumulation rate, with thinning by pure shear according to Nye (1963). The stratigraphy does not seem to have been obliterated by meltwater percolation, in contrast to most previous core sites on Svalbard. The anthropogenic influence on the Svalbard environment is illustrated by increased levels of sulphate, nitrate and acidity. Both nitrate and sulphate levels started to increase in the late 1940s, remained high until the late 1980s and have decreased during the last 15 years. The records of delta O-18, MSA (methanesulphonic acid), and melt features along the core agree with the temperature record from Longycarbyen and the sea-ice record from the Barents Sea at a multi-year resolution, suggesting that this ice core reflects local climatic conditions.

  • 7. Kekonen, T
    et al.
    Moore, J
    Peramaki, P
    Mulvaney, R
    Isaksson, E
    Pohjola, V
    van de Wal, R S W
    The 800 year long ion record from the Lomonosovfonna (Svalbard) ice core2005In: Journal of Geophysical Research - Atmospheres, ISSN 2169-897X, E-ISSN 2169-8996, Vol. 110, no D7, article id D07304Article in journal (Refereed)
    Abstract [en]

    We present a high-resolution record of water-soluble ion chemistry from a 121 m ice core spanning about 800 years. The core is well dated to 2/3 depth using cycle counting and reference horizons and a simple but close fitting model for the lower 1/3 of the core. This core suffers from modest seasonal melt, and so we present concentration data in decadal running means to minimize percolation effects. Sea-salt ions (Na+, Cl-, Mg2+, and K+) account for more than 70% of all ions. In general, sea-salt ion concentrations are rather variable and have no clear association with climatic variations. Sulfate, with 74% being from non-sea-salt sources, has higher concentrations than seen on Vestfonna ice cap but lower than in Ny-angstrom lesund aerosols, suggesting central Spitsbergen receives more marine (westerly) air masses than Ny-angstrom lesund but more sulfate enriched (easterly) air masses than Nordaustlandet. Clear anthropogenic impacts are found for sulfate, nitrate, and ammonium (and probably excess chloride) after the mid twentieth century, with sulfate showing a significant rise by the end of the nineteenth century. Sulfate and methanesulfonate concentrations correlate well during the twentieth century, and it is clear that most of the preindustrial sulfate is of biogenic origin. Terrestrial component (Ca2+) has the highest concentrations in the coldest part of the Little Ice Age, suggesting more windy conditions, transporting local terrestrial dust to the ice cap. All ion concentrations decrease at the end of the twentieth century, which reflects loss of ions by runoff, with non-sea-salt magnesium being particularly sensitive to melting.

  • 8. O'Dwyer, J
    et al.
    Isaksson, E
    Vinje, T
    Jauhiainen, T
    Moore, J
    Pohjola, V
    Vaikmae, R
    van de Wal, R S W
    Methanesulfonic acid in a Svalbard ice core as an indicator of ocean climate2000In: Geophysical Research Letters, ISSN 0094-8276, E-ISSN 1944-8007, Vol. 27, no 8, p. 1159-1162Article in journal (Refereed)
    Abstract [en]

    Methanesulfonic acid (MSA) is an atmospheric oxidation product of dimethyl sulfide, produced by marine biota. MSA preserved in a Svalbard glacier between 1920 and 1996 is compared with the sea surface temperature (SST) and sea-ice extent of the surrounding ocean over the same period. On decadal timescales high MSA concentrations are found to be associated with warm SST and reduced sea-ice extent. MSA appears to be influenced by climatic changes related to variations in the import of warm Atlantic Water to the Barents Sea. Atlantic Water plays an important role in the Arctic climate system, therefore MSA concentrations may indirectly reflect larger-scale changes in the region and may be useful as a proxy for past climate.

  • 9.
    Pohjola, Veijo A.
    et al.
    Uppsala Univ, Dept Earth Sci, S-75236 Uppsala, Sweden.;Uppsala Univ, Dept Earth Sci Air Water & Landscape Sci, S-75236 Uppsala, Sweden..
    Kankaanpaa, Paula
    Univ Lapland, Arctic Ctr, FI-96101 Rovaniemi, Finland..
    Moore, John C.
    Univ Lapland, Arctic Ctr, FI-96101 Rovaniemi, Finland.;Beijing Normal Univ, Coll Global Change & Earth Syst Sci, Beijing 100875, Peoples R China.;Uppsala Univ, Dept Earth Sci Air Water & Landscape Sci, S-75236 Uppsala, Sweden..
    Pastusiak, Tadeusz
    Gdynia Maritime Univ, PL-81345 Gdynia, Poland..
    PREFACE: THE INTERNATIONAL POLAR YEAR PROJECT KINNVIKA'- ARCTIC WARMING AND IMPACT RESEARCH AT 80 degrees N2011In: Geografiska Annaler. Series A, Physical Geography, ISSN 0435-3676, E-ISSN 1468-0459, Vol. 93A, no 4, p. 201-208Article in journal (Other academic)
1 - 9 of 9
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