Change search
Refine search result
1 - 7 of 7
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Rows per page
  • 5
  • 10
  • 20
  • 50
  • 100
  • 250
Sort
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
Select
The maximal number of hits you can export is 250. When you want to export more records please use the 'Create feeds' function.
  • 1. Aartsen, M. G.
    et al.
    Abbasi, R.
    Abdou, Y.
    Ackermann, M.
    Adams, J.
    Aguilar, J. A.
    Ahlers, M.
    Altmann, D.
    Auffenberg, J.
    Bai, X.
    Baker, M.
    Barwick, S. W.
    Baum, V.
    Bay, R.
    Beatty, J. J.
    Bechet, S.
    Becker, K. H.
    Tjus, J. B.
    Bell, M.
    Benabderrahmane, M. L.
    BenZvi, S.
    Berdermann, J.
    Berghaus, P.
    Berley, D.
    Bernardini, E.
    Bernhard, A.
    Bertrand, D.
    Besson, D. Z.
    Binder, G.
    Bindig, D.
    Bissok, M.
    Blaufuss, E.
    Blumenthal, J.
    Boersma, D. J.
    Bohaichuk, S.
    Bohm, C.
    Bose, D.
    Boser, S.
    Botner, O.
    Brayeur, L.
    Bretz, H. P.
    Brown, A. M.
    Bruijn, R.
    Brunner, J.
    Carson, M.
    Casey, J.
    Casier, M.
    Cherwinka, J.
    Chirkin, D.
    Christov, A.
    Christy, B.
    Clark, K.
    Clevermann, F.
    Coenders, S.
    Cohen, S.
    Cowen, D. F.
    Silva, A. H. C.
    Danninger, M.
    Daughhetee, J.
    Davis, J. C.
    De Clercq, C.
    De Ridder, S.
    Desiati, P.
    de With, M.
    DeYoung, T.
    Diaz-Velez, J. C.
    Dunkman, M.
    Eagan, R.
    Eberhardt, B.
    Eisch, J.
    Ellsworth, R. W.
    Euler, S.
    Evenson, P. A.
    Fadiran, O.
    Fazely, A. R.
    Fedynitch, A.
    Feintzeig, J.
    Feusels, T.
    Filimonov, K.
    Finley, C.
    Fischer-Wasels, T.
    Flis, S.
    Franckowiak, A.
    Franke, R.
    Frantzen, K.
    Fuchs, T.
    Gaisser, T. K.
    Gallagher, J.
    Gerhardt, L.
    Gladstone, L.
    Glusenkamp, T.
    Goldschmidt, A.
    Golup, G.
    Gonzalez, J. G.
    Goodman, J. A.
    Gora, D.
    Grant, D.
    Gross, A.
    Gurtner, M.
    Ha, C.
    Ismail, A. H.
    Hallen, P.
    Hallgren, A.
    Halzen, F.
    Hanson, K.
    Heereman, D.
    Heinen, D.
    Helbing, K.
    Hellauer, R.
    Hickford, S.
    Hill, G. C.
    Hoffman, K. D.
    Hoffmann, R.
    Homeier, A.
    Hoshina, K.
    Huelsnitz, W.
    Hulth, P. O.
    Hultqvist, K.
    Hussain, S.
    Ishihara, A.
    Jacobi, E.
    Jacobsen, J.
    Jagielski, K.
    Japaridze, G. S.
    Jero, K.
    Jlelati, O.
    Kaminsky, B.
    Kappes, A.
    Karg, T.
    Karle, A.
    Kelley, J. L.
    Kiryluk, J.
    Kislat, F.
    Klas, J.
    Klein, S. R.
    Kohne, J. H.
    Kohnen, G.
    Kolanoski, H.
    Kopke, L.
    Kopper, C.
    Kopper, S.
    Koskinen, D. J.
    Kowalski, M.
    Krasberg, M.
    Krings, K.
    Kroll, G.
    Kunnen, J.
    Kurahashi, N.
    Kuwabara, T.
    Labare, M.
    Landsman, H.
    Larson, M. J.
    Lesiak-Bzdak, M.
    Leuermann, M.
    Leute, J.
    Lunemann, J.
    Madsen, J.
    Maruyama, R.
    Mase, K.
    Matis, H. S.
    McNally, F.
    Meagher, K.
    Merck, M.
    Meszaros, P.
    Meures, T.
    Miarecki, S.
    Midden, E.
    Milke, N.
    Miller, J.
    Mohrmann, L.
    Montaruli, T.
    Morse, R.
    Nahnhauer, R.
    Naumann, U.
    Niederhausen, H.
    Nowicki, S. C.
    Nygren, D. R.
    Obertacke, A.
    Odrowski, S.
    Olivas, A.
    Olivo, M.
    O'Murchadha, A.
    Paul, L.
    Pepper, J. A.
    de los Heros, C. P.
    Pfendner, C.
    Pieloth, D.
    Pinat, E.
    Pirk, N.
    Posselt, J.
    Price, P. B.
    Przybylski, G. T.
    Radel, L.
    Rameez, M.
    Rawlins, K.
    Red, P.
    Reimann, R.
    Resconi, E.
    Rhode, W.
    Ribordy, M.
    Richman, M.
    Riede, B.
    Rodrigues, J. P.
    Rott, C.
    Ruhe, T.
    Ruzybayev, B.
    Ryckbosch, D.
    Saba, S. M.
    Salameh, T.
    Sander, H. G.
    Santander, M.
    Sarkar, S.
    Schatto, K.
    Scheel, M.
    Scheriau, F.
    Schmidt, T.
    Schmitz, M.
    Schoenen, S.
    Schoneberg, S.
    Schonwald, A.
    Schukraft, A.
    Schulte, L.
    Schulz, O.
    Seckel, D.
    Sestayo, Y.
    Seunarine, S.
    Sheremata, C.
    Smith, M. W. E.
    Soiron, M.
    Soldin, D.
    Spiczak, G. M.
    Spiering, C.
    Stamatikos, M.
    Stanev, T.
    Stasik, A.
    Stezelberger, T.
    Stokstad, R. G.
    Stossl, A.
    Strahler, E. A.
    Strom, R.
    Sullivan, G. W.
    Taavola, H.
    Taboada, I.
    Tamburro, A.
    Ter-Antonyan, S.
    Tesic, G.
    Tilay, S.
    Toale, P. A.
    Toscano, S.
    Tosi, D.
    Usner, M.
    van der Drift, D.
    van Eijndhoven, N.
    Van Overloop, A.
    van Santen, J.
    Vehring, M.
    Voge, M.
    Vraeghe, M.
    Walck, C.
    Waldenmaier, T.
    Wallraff, M.
    Wasserman, R.
    Weaver, C.
    Wellons, M.
    Wendt, C.
    Westerhoff, S.
    Whitehorn, N.
    Wiebe, K.
    Wiebusch, C. H.
    Williams, D. R.
    Wissing, H.
    Wolf, M.
    Wood, T. R.
    Woschnagg, K.
    Xu, C.
    Xu, D. L.
    Xu, X. W.
    Yanez, J. P.
    Yodh, G.
    Yoshida, S.
    Zarzhitsky, P.
    Ziemann, J.
    Zierke, S.
    Zilles, A.
    Zoll, M.
    IceCube, Collaboration
    South Pole glacial climate reconstruction from multi-borehole laser particulate stratigraphy2013In: Journal of Glaciology, ISSN 0022-1430, E-ISSN 1727-5652, Vol. 59Article in journal (Refereed)
    Abstract [en]

    The IceCube Neutrino Observatory and its prototype, AMANDA, were built in South Pole ice, using powerful hot-water drills to cleanly bore >100 holes to depths up to 2500 m. The construction of these particle physics detectors provided a unique opportunity to examine the deep ice sheet using a variety of novel techniques. We made high-resolution particulate profiles with a laser dust logger in eight of the boreholes during detector commissioning between 2004 and 2010. The South Pole laser logs are among the most clearly resolved measurements of Antarctic dust strata during the last glacial period and can be used to reconstruct paleoclimate records in exceptional detail. Here we use manual and algorithmic matching to synthesize our South Pole measurements with ice-core and logging data from Dome C, East Antarctica. We derive impurity concentration, precision chronology, annual-layer thickness, local spatial variability, and identify several widespread volcanic ash depositions useful for dating. We also examine the interval around similar to 74 ka recently isolated with radiometric dating to bracket the Toba (Sumatra) supereruption.

  • 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. 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.

  • 4. Marchenko, Sergey
    et al.
    Pohjola, Veijo A.
    Pettersson, Rickard
    Van Pelt, Ward J. J.
    Vega, Carmen P.
    Machguth, Horst
    Boggild, Carl E.
    Isaksson, Elisabeth
    A plot-scale study of firn stratigraphy at Lomonosovfonna, Svalbard, using ice cores, borehole video and GPR surveys in 2012-142017In: Journal of Glaciology, ISSN 0022-1430, E-ISSN 1727-5652, Vol. 63, no 237, p. 67-78Article in journal (Refereed)
    Abstract [en]

    Spatial heterogeneity of snow and firn properties on glaciers introduces uncertainty in interpretation of point and profile observations and complicates modelling of meltwater percolation and runoff. Here we present a study of the temporal and spatial dynamics of firn density and stratigraphy at the plot-scale (approximate to 10 m x 10 m x 10 m) repeated annually during 2012-14 at the Lomonosovfonna ice-field, Svalbard. Results from cores, video inspections in boreholes and radar grid surveys are compared. Ice layers 0.1-50 cm thick comprised approximate to 8% of the borehole length. Most of them are 1-3 cm thick and could not be traced between boreholes separated by 3 m. Large lateral variability of firn structure affects representativeness of observations in single holes and calls for repeated studies in multiple points to derive a representative stratigraphy signal. Radar reflections are poorly correlated with ice layers in individual boreholes. However, the match between the high amplitude peaks in the grid-averaged radar signal and horizons of preferential ice layer formation revealed by averaging the video surveys over multiple boreholes is higher. These horizons are interpreted as buried firn layers previously exposed to melt-freeze or wind-driven densification and several of them are consistently recovered throughout three field campaigns.

  • 5. Sugiyama, S.
    et al.
    Enomoto, H.
    Fujita, S.
    Fukui, K.
    Nakazawa, F.
    Holmlund, P.
    Surdyk, S.
    Snow density along the route traversed by the Japanese-Swedish Antarctic Expedition 2007/082012In: Journal of Glaciology, ISSN 0022-1430, E-ISSN 1727-5652, Vol. 58Article in journal (Refereed)
    Abstract [en]

    During the Japanese-Swedish Antarctic traverse expedition of 2007/08, we measured the surface snow density at 46 locations along the 2800 km long route from Syowa station to Wasa station in East Antarctica. The mean snow density for the upper 1 (or 0.5) m layer varied from 333 to 439 kg m(-3) over a region spanning an elevation range of 365-3800 m a.s.l. The density variations were associated with the elevation of the sampling sites; the density decreased as the elevation increased, moving from the coastal region inland. However, the density was relatively insensitive to the change in elevation along the ridge on the Antarctic plateau between Dome F and Kohnen stations. Because surface wind is weak in this region, irrespective of elevation, the wind speed was suggested to play a key role in the near-surface densification. The results of multiple regression performed on the density using meteorological variables were significantly improved by the inclusion of wind speed as a predictor. The regression analysis yielded a linear dependence between the density and the wind speed, with a coefficient of 13.5 kg m(-3) (m s(-1))(-1). This relationship is nearly three times stronger than a value previously computed from a dataset available in Antarctica. Our data indicate that the wind speed is more important to estimates of the surface snow density in Antarctica than has been previously assumed.

  • 6.
    van der Wel, L. G.
    et al.
    Univ Groningen, Ctr Isotope Res, NL-9747 AG Groningen, Netherlands..
    Streurman, H. J.
    Univ Groningen, Ctr Isotope Res, NL-9747 AG Groningen, Netherlands..
    Isaksson, E.
    Norwegian Environm Ctr, Norwegian Polar Inst, NO-9005 Tromso, Norway..
    Helsen, M. M.
    Univ Utrecht, Inst Marine & Atmospher Res, NL-3584 CC Utrecht, Netherlands..
    van de Wal, R. S. W.
    Univ Utrecht, Inst Marine & Atmospher Res, NL-3584 CC Utrecht, Netherlands..
    Martma, T.
    Tallinn Univ Technol, Inst Geol, EE-10143 Tallinn, Estonia..
    Pohjola, V. A.
    Uppsala Univ, Dept Earth Sci, SE-75236 Uppsala, Sweden..
    Moore, J. C.
    Univ Lapland, Arctic Ctr, FIN-96101 Rovaniemi, Finland..
    Meijer, H. A. J.
    Univ Groningen, Ctr Isotope Res, NL-9747 AG Groningen, Netherlands..
    Using high-resolution tritium profiles to quantify the effects of melt on two Spitsbergen ice cores2011In: Journal of Glaciology, ISSN 0022-1430, E-ISSN 1727-5652, Vol. 57, no 206, p. 1087-1097Article in journal (Refereed)
    Abstract [en]

    Ice cores from small ice caps provide valuable climatic information, additional to that of Greenland and Antarctica. However, their integrity is usually compromised by summer meltwater percolation. To determine to what extent this can affect such ice cores, we performed high-resolution tritium measurements on samples from two ice cores from Spitsbergen covering the period AD1955-75. The very sharp and distinct peaks in the tritium precipitation record are subject to several post-depositional processes. We developed a model that uses the precipitation record as input and incorporates the three most important processes (radioactive decay, isotope diffusion and meltwater percolation). Results are compared with measured tritium and density profiles. Both ice-core records contain sharp bomb peaks in the pre-1963 period. It is shown that these peaks would be much smoother in the absence of melt. In this case the main effect of melt and the refreezing of percolation water is the formation of ice layers that form barriers for firn diffusion; thus melt paradoxically results in better preservation of the annual isotope signals. Conversely, for the period after 1963 the main effect of melt is a stronger smoothing of the tritium profiles.

  • 7.
    Virkkunen, K.
    et al.
    Univ Lapland, Arctic Ctr, FIN-96101 Rovaniemi, Finland.;Univ Oulu, Dept Chem, FIN-90014 Oulu, Finland..
    Moore, J. C.
    Univ Lapland, Arctic Ctr, FIN-96101 Rovaniemi, Finland..
    Isaksson, E.
    Norwegian Polar Res Inst, Polar Environm Ctr, NO-9296 Tromso, Norway..
    Pohjola, V.
    Uppsala Univ, Dept Earth Sci, SE-75236 Uppsala, Sweden..
    Peramaki, P.
    Univ Oulu, Dept Chem, FIN-90014 Oulu, Finland..
    Grinsted, A.
    Univ Lapland, Arctic Ctr, FIN-96101 Rovaniemi, Finland.;Univ Oulu, Dept Geophys, FIN-90014 Oulu, Finland..
    Kekonen, T.
    Univ Lapland, Arctic Ctr, FIN-96101 Rovaniemi, Finland.;Univ Oulu, Dept Chem, FIN-90014 Oulu, Finland..
    Warm summers and ion concentrations in snow: comparison of present day with Medieval Warm Epoch from snow pits and an ice core from Lomonosovfonna, Svalbard2007In: Journal of Glaciology, ISSN 0022-1430, E-ISSN 1727-5652, Vol. 53, no 183, p. 623-634Article in journal (Refereed)
    Abstract [en]

    Snow pits sampled during two consecutive years (2001, 2002) at the summit of Lomonosovfonna ice cap in central Spitsbergen, Svalbard, showed that ion concentrations were spatially homogeneous. The snowpack on Lomonosovfonna shows no evidence of aerosol deposition from Arctic haze, in contrast to Holtedahlfonna (a glacier at a similar altitude in northern Spitsbergen) where there is a clear signature. In common with many other ice caps in the Arctic, Lomonosovfonna experiences periodic melting, and the deepest of the snow pits contained a record of one exceptionally warm (2001) and one long summer (2000). The most easily eluted species are nitrate and the divalent ions. Very low ion concentrations and high values of a melt indicator log([Na(+)]/[Mg(2+)]) were a result of either deep percolation or runoff of ions during melting. Comparing the snow-pit record with the ion record of more than 800 years from an ice core drilled on Lomonosovfonna in 1997 reveals some layers with similar composition to those that suffered significant melting in the snowpack: a few years in the 20th century and around AD 1750, and all of the core from before AD 1200 show unusually heavy melting.

1 - 7 of 7
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf