Change search
Refine search result
1 - 6 of 6
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. Alfimov, Vasily
    et al.
    Aldahan, Ala
    Possnert, Goran
    Water masses and I-129 distribution in the Nordic Seas2013In: Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms, ISSN 0168-583X, E-ISSN 1872-9584, Vol. 294, p. 542-546Article in journal (Refereed)
    Abstract [en]

    The application of the radioactive isotope iodine-129 as a tracer of water circulation in the oceans has provided interesting information with respect to sources and mixing of different water masses. We here present results of I-129 distribution in water profiles located in the Nordic Seas and use the isotope to fingerprint water masses in the region. The samples were collected by the US research vessel Knorr in May-June 2002. I-129 signatures along the Norwegian Sea reflect a mixing of I-129-rich surface water along the Scandinavian continental slope and I-129-poor North Atlantic surface water. These two water masses become less segregated along the Fram Strait where apparent I-129 enrichment penetrates the return Arctic flow into the East Greenland Current. The I-129 data further suggest existence of a water mass that is not entirely labeled with respect to origin at the Denmark Strait bottom water. This water parcel probably originates from the Iceland Sea. I-129 data also shed light on the major deep water outflow from the Nordic Seas located at the Faeroe Bank Channel. (C) 2012 Elsevier B.V. All rights reserved.

  • 2. Berggren, A. -M
    et al.
    Aldahan, A.
    Possnert, G.
    Hansson, M.
    Steen-Larsen, H. C.
    Storm, A. Sturevik
    Morth, C. -M
    Murad, A.
    Variability of Be-10 and delta O-18 in snow pits from Greenland and a surface traverse from Antarctica2013In: Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms, ISSN 0168-583X, E-ISSN 1872-9584, Vol. 294, p. 568-572Article in journal (Refereed)
    Abstract [en]

    To examine temporal variability of Be-10 in glacial ice, we sampled snow to a depth of 160 cm at the NEEM (North Greenland Eemian Ice Drilling) drilling site in Greenland. The samples span three years between the summers of 2006 and 2009. At the same time, spatial variability of Be-10 in glacial ice was explored through collection of the upper similar to 5 cm of surface snow in Antarctica during part of the Swedish-Japanese traverse from Svea to Syowa station during the austral summer in 2007-2008. The results of the Greenlandic 1 Be snow suggested variable concentrations that apparently do not clearly reflect the seasonal change as indicated by the delta O-18 data. The Be-10 concentration variability most likely reflects also effects of aerosol loading and deposition pathways, possibly in combination with post-depositional processes. The Antarctic traverse data expose a negative correlation between Be-10 and delta O-18, while there are weaker but still significant correlations to altitude and distance to the coast (approximated by the distance to the 70th latitude). These relationships indicate that geographical factors, mainly the proximity to the coast, may strongly affect 1 Be concentrations in snow in Queen Maud Land, Antarctica. (C) 2012 Elsevier B.V. All rights reserved.

  • 3. He, Peng
    et al.
    Aldahan, A.
    Possnert, G.
    Hou, X. L.
    A summary of global I-129 in marine waters2013In: Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms, ISSN 0168-583X, E-ISSN 1872-9584, Vol. 294, p. 537-541Article in journal (Refereed)
    Abstract [en]

    Despite the many investigations concerning the occurrence of anthropogenic iodine-129 in the atmosphere, terrestrial and marine environments, there is a lack of a comprehensive collection of data on the distribution of the isotope in marine waters. The temporal and spatial variability of anthropogenic I-129 is strongly linked to the major point sources in the Irish Sea and the English Channel and the global marine spreading pathways are partly outlined from these sources. The temporal evolution is still, however, not well defined when transport and dissipation are considered in the different oceans and ocean compartments. We here summarize available published literature data on I-129 temporal and spatial distribution in the global marine water. The results show presence of numerous data sets for the North Atlantic and Arctic Oceans where strong variability in terms of water depth, time and location also occur. Scarcity of data on I-129 from the Pacific, Indian and South Atlantic Oceans demonstrates gaps in the coverage of the isotope spatial extent. These shortcomings in the spatial coverage may relate to the understanding that the anthropogenic I-129 signal will take a long time to be transported, if at all, from the North Atlantic into other oceans. Data from recent expeditions in the Southern oceans and the Geotraces ocean profiling will reveal additional information about I-129 distribution in the marine waters. (C) 2012 Elsevier B.V. All rights reserved.

  • 4.
    Lachner, Johannes
    et al.
    Swiss Fed Inst Technol, Lab Ion Beam Phys, Zurich, Switzerland..
    Christl, Marcus
    Swiss Fed Inst Technol, Lab Ion Beam Phys, Zurich, Switzerland..
    Synal, Hans-Arno
    Swiss Fed Inst Technol, Lab Ion Beam Phys, Zurich, Switzerland..
    Frank, Martin
    CAU Kiel, IFM Geomar, Kiel, Germany..
    Jakobsson, Martin
    Univ Stockholm, Dept Geol Sci, S-10691 Stockholm, Sweden..
    Carrier free Be-10/Be-9 measurements with low-energy AMS: Determination of sedimentation rates in the Arctic Ocean2013In: Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms, ISSN 0168-583X, E-ISSN 1872-9584, Vol. 294, p. 67-71Article in journal (Refereed)
    Abstract [en]

    Using the TANDY AMS facility (600 kV) at ETH Zurich the seawater-derived (authigenic) Be-10/Be-9 ratio of marine sediment samples is measured without the addition of Be-9 carrier. This novel method reduces systematic uncertainties because the Be-10/Be-9 ratio of a sample is determined in only one (AMS) measurement. A challenge of carrier-free AMS is to avoid any contamination of the sample with Be-9 during the chemical preparation. Further, the leaching procedure has to be reproducible and ideally should attack the authigenic Be of the sediments only, leaving the detrital Be untouched. The low amount of stable Be-9 in the unspiked samples causes low currents during the AMS measurement. This requires a good stability and sensitivity of the AMS setup. Our first results show that the new preparation method is reliable and that background from stable Be-9 is avoided. For a comparison study, sediment samples from two cores located in the Arctic Ocean (HLY0503-09JPC, HLY0503-14JPC) were used. The authigenic Be-10/Be-9 ratio of these samples had been determined previously applying the conventional method where Be-10 and Be-9 concentrations are measured separately by AMS and ICP-MS, respectively. The resulting sedimentation rates are in discrepancy with values derived from biomarkers. To cross check the Be-10/Be-9 based age model two samples from each core were measured again with the new carrier-free method. The carrier-free results show systematically higher authigenic Be-10/Be-9 ratios. The calculated sedimentation rates of about 0.2 cm/kyr, however, are consistent for the carrier free and the conventional method. (C) 2012 Elsevier B.V. All rights reserved.

  • 5. Persson, S.
    et al.
    Aldahan, A.
    Possnert, G.
    Alfimov, V.
    Hou, X.
    I-129 Variability in precipitation over Europe2007In: Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms, ISSN 0168-583X, E-ISSN 1872-9584, Vol. 259, no 1, p. 508-512Article in journal (Refereed)
    Abstract [en]

    We present results and an overview of studies on I-129 in precipitation over Europe during the last decade, covering latitudes 37-70 degrees N. The data show about three orders of magnitude variability in concentrations but without specific correlation to latitude when all Europe is considered. The total amount of I-129 provided annually by precipitation over Europe composes only a tiny portion of the annual marine discharge but a significant portion of the gaseous discharges from the nuclear reprocessing facilities. Contribution of gaseous releases seems to be significant, although difficult to estimate. As shown by this study, a unified sampling procedure and systematic measurements of I-129 in precipitation throughout Europe are needed to achieve a coherent picture about the loading and sources of I-129 in precipitation and the atmosphere. (c) 2007 Elsevier B.V. All rights reserved.

  • 6. Sjunneskog, C.
    et al.
    Scherer, R.
    Aldahan, A.
    Possnert, G.
    Be-10 in glacial marine sediment of the Ross Sea, Antarctica, a potential tracer of depositional environment and sediment chronology2007In: Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms, ISSN 0168-583X, E-ISSN 1872-9584, Vol. 259, no 1, p. 576-583Article in journal (Refereed)
    Abstract [en]

    Beryllium isotopes ((9)Bc and Be-10) distribution in Holocene and late Pleistocene glacial ice and sediment facies from sub-ice stream and sub-ice shelf settings of the Ross sector of the West Antarctic Ice Sheet (WAIS) and from the open Ross Sea are presented, to assess the temporal and spatial variability of these tracers. Significant variation is detected (> one order of magnitude) among Holocene post-glacial deposits. Late Pleistocene diamictons from bathymetric lows in the Ross Sea show depleted concentrations that are less variable among sites and distinctly lower than bank deposits of similar age. In general, sub-ice shelf and ice stream sediments are the most depleted in Be-10. Be-10 with its longer half-life and different pathways compared apparant to C-14 is found to be a sensitive marker for evaluating the complex spatial and temporal relationships between texturally similar sediments formed by different depositional processes. (c) 2007 Elsevier B.V. All rights reserved.

1 - 6 of 6
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