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  • 1. Adolphi, Florian
    et al.
    Muscheler, Raimund
    Svensson, Anders
    Aldahan, Ala
    Possnert, Göran
    Uppsala University, Disciplinary Domain of Science and Technology, För teknisk-naturvetenskapliga fakulteten gemensamma enheter, Tandem Laboratory.
    Beer, Jurg
    Sjolte, Jesper
    Bjorck, Svante
    Matthes, Katja
    Thieblemont, Remi
    Persistent link between solar activity and Greenland climate during the Last Glacial Maximum2014In: Nature Geoscience, ISSN 1752-0894, E-ISSN 1752-0908, Vol. 7, no 9, p. 662-666Article in journal (Refereed)
    Abstract [en]

    Changes in solar activity have previously been proposed to cause decadal- to millennial-scale fluctuations in both the modern and Holocene climates(1). Direct observational records of solar activity, such as sunspot numbers, exist for only the past few hundred years, so solar variability for earlier periods is typically reconstructed from measurements of cosmogenic radionuclides such as Be-10 and C-14 from ice cores and tree rings(2,3). Here we present a high-resolution Be-10 record from the ice core collected from central Greenland by the Greenland Ice Core Project (GRIP). The record spans from 22,500 to 10,000 years ago, and is based on new and compiled data(4-6). Using C-14 records(7,8) to control for climate-related influences on Be-10 deposition, we reconstruct centennial changes in solar activity. We find that during the Last Glacial Maximum, solar minima correlate with more negative delta O-18 values of ice and are accompanied by increased snow accumulation and sea-salt input over central Greenland. We suggest that solar minima could have induced changes in the stratosphere that favour the development of high-pressure blocking systems located to the south of Greenland, as has been found in observations and model simulations for recent climate(9,10). We conclude that the mechanism behind solar forcing of regional climate change may have been similar under both modern and Last Glacial Maximum climate conditions.

    Publisher's full text
  • 2. Aho-Mantila, L.
    et al.
    Andersson Sundén, Erik
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Asp, E.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Binda, Federico
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Cecconello, Marco
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Conroy, Sean
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Dzysiuk, Nataliia
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Ericsson, Göran
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Eriksson, Jacob
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Hellesen, Carl
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Hjalmarsson, Anders
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Possnert, Göran
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Sjöstrand, Henrik
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Skiba, Mateusz
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Weiszflog, Matthias
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Zychor, I.
    Assessment of SOLPS5.0 divertor solutions with drifts and currents against L-mode experiments in ASDEX Upgrade and JET2017In: Plasma Physics and Controlled Fusion, ISSN 0741-3335, E-ISSN 1361-6587, Vol. 59, no 3, article id 035003Article in journal (Refereed)
    Abstract [en]

    The divertor solutions obtained with the plasma edge modelling tool SOLPS5.0 are discussed. The code results are benchmarked against carefully analysed L-mode discharges at various density levels with and without impurity seeding in the full-metal tokamaks ASDEX Upgrade and JET. The role of the cross-field drifts and currents in the solutions is analysed in detail, and the improvements achieved by fully activating the drift and current terms in view of matching the experimental signals are addressed. The persisting discrepancies are also discussed.

    Publisher's full text
  • 3.
    Aiba, N.
    et al.
    Natl Inst Quantum & Radiol Sci & Technol, Rokkasho, Aomori, Japan.
    Andersson Sundén, Erik
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Andersson Sundén, Erik
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Cecconello, Marco
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Conroy, Sean
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Dzysiuk, Nataliia
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Ericsson, Göran
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Eriksson, Jacob
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Hellesen, Carl
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Hjalmarsson, Anders
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Possnert, Göran
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Possnert, Göran
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Skiba, Mateusz
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Weiszflog, Matthias
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Zychor, I.
    Natl Ctr Nucl Res, Otwock, Poland.
    Analysis of ELM stability with extended MHD models in JET, JT-60U and future JT-60SA tokamak plasmas2018In: Plasma Physics and Controlled Fusion, ISSN 0741-3335, E-ISSN 1361-6587, Vol. 60, no 1, article id 014032Article in journal (Refereed)
    Abstract [en]

    The stability with respect to a peeling-ballooning mode (PBM) was investigated numerically with extended MHD simulation codes in JET, JT-60U and future JT-60SA plasmas. The MINERVA-DI code was used to analyze the linear stability, including the effects of rotation and ion diamagnetic drift (omega(*i)), in JET-ILW and JT-60SA plasmas, and the JOREK code was used to simulate nonlinear dynamics with rotation, viscosity and resistivity in JT-60U plasmas. It was validated quantitatively that the ELM trigger condition in JET-ILW plasmas can be reasonably explained by taking into account both the rotation and omega(*i) effects in the numerical analysis. When deuterium poloidal rotation is evaluated based on neoclassical theory, an increase in the effective charge of plasma destabilizes the PBM because of an acceleration of rotation and a decrease in omega(*i). The difference in the amount of ELM energy loss in JT-60U plasmas rotating in opposite directions was reproduced qualitatively with JOREK. By comparing the ELM affected areas with linear eigenfunctions, it was confirmed that the difference in the linear stability property, due not to the rotation direction but to the plasma density profile, is thought to be responsible for changing the ELM energy loss just after the ELM crash. A predictive study to determine the pedestal profiles in JT-60SA was performed by updating the EPED1 model to include the rotation and w*i effects in the PBM stability analysis. It was shown that the plasma rotation predicted with the neoclassical toroidal viscosity degrades the pedestal performance by about 10% by destabilizing the PBM, but the pressure pedestal height will be high enough to achieve the target parameters required for the ITER-like shape inductive scenario in JT-60SA.

    Publisher's full text
  • 4. Aiba, N.
    et al.
    Andersson Sundén, Erik
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Binda, Federico
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Cecconello, Marco
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Conroy, Sean
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Dzysiuk, Nataliia
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Ericsson, Göran
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Eriksson, Jacob
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Hellesen, Carl
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Hjalmarsson, Anders
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Possnert, Göran
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Sjöstrand, Henrik
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Skiba, Mateusz
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Weiszflog, Matthias
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Zychor, I.
    Numerical analysis of ELM stability with rotation and ion diamagnetic drift effects in JET2017In: Nuclear Fusion, ISSN 0029-5515, E-ISSN 1741-4326, Vol. 57, no 12, article id 126001Article in journal (Refereed)
    Abstract [en]

    Stability to the type-I edge localized mode (ELM) in JET plasmas was investigated numerically by analyzing the stability to a peeling-ballooning mode with the effects of plasma rotation and ion diamagnetic drift. The numerical analysis was performed by solving the extended Frieman-Rotenberg equation with the MINERVA-DI code. To take into account these effects in the stability analysis self-consistently, the procedure of JET equilibrium reconstruction was updated to include the profiles of ion temperature and toroidal rotation, which are determined based on the measurement data in experiments. With the new procedure and MINERVA-DI, it was identified that the stability analysis including the rotation effect can explain the ELM trigger condition in JET with ITER like wall (JET-ILW), though the stability in JET with carbon wall (JET-C) is hardly affected by rotation. The key difference is that the rotation shear in JET-ILW plasmas analyzed in this study is larger than that in JET-C ones, the shear which enhances the dynamic pressure destabilizing a peeling-ballooning mode. In addition, the increase of the toroidal mode number of the unstable MHD mode determining the ELM trigger condition is also important when the plasma density is high in JET-ILW. Though such modes with high toroidal mode number are strongly stabilized by the ion diamagnetic drift effect, it was found that plasma rotation can sometimes overcome this stabilizing effect and destabilizes the peeling-ballooning modes in JET-ILW.

    Publisher's full text
  • 5.
    Aldahan, A A
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences. Technology, Department of Engineering Sciences, Ion Physics.
    Possnert, G
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Engineering Sciences. Technology, Department of Engineering Sciences, Ion Physics. Jonfysik.
    Geomagnetic and climatic variability reflected by 10Be during the Quaternary and late Pliocene2003In: Geophysical Research Letter, Vol. 30, no 6Article in journal (Refereed)
  • 6.
    Aldahan, A
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences.
    Possnert, G
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Engineering Sciences. Jonfysik.
    The Be-10 marine record of the last 3.5 Ma2000In: NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS, ISSN 0168-583X, Vol. 172, p. 513-517Article in journal (Refereed)
    Abstract [en]

    We present in this study a Be-10 profile from a deep-sea sediment section extending to 3.5 Ma. The Be-10 concentration ranges at 2-14 x 10(8) atoms/g and shows a clear decay trend. The flux of Be-10 ranges at 1-5 x 10(6) atoms/cm(2) y and averages at appr

  • 7.
    Aldahan, A
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences.
    Possnert, G
    Burgalio, N
    Meili, M
    Kekli, A
    129I in precipitation over Sweden. 6th International conference on Acid Rain,2000In: 6th International conference on Acid Rain, 10-16 December, 2000, p. p.68-Conference paper (Other scientific)
  • 8.
    Aldahan, A
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences. ELD.
    Possnert, G
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Engineering Sciences. jonfysik.
    Gard, G
    10Be in two sediment sections from the North Atlantic and chronological implications for the Late Quaternary1994In: Nues Jar. Geol. Paleon. Mh, Vol. H7, p. 418-433Article in journal (Refereed)
  • 9.
    Aldahan, A
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences. ELD.
    Possnert, G
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Engineering Sciences. jonfysik.
    Olausson, E
    10Be distribution in sediments of two cores from the North Atlantic: an approach for evaluating environmental change1992In: Bull. Geol. Inst. Uppsala, Vol. 16, p. 69-80Article in journal (Refereed)
  • 10.
    Aldahan, A
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences.
    Possnert, G
    Scherer, R
    Shi, Ning
    Backman, J
    Boström, K
    Trace-element and major-element stratigraphy in quaternary sediments from the Arctic Ocean and implications for glacial termination2000In: JOURNAL OF SEDIMENTARY RESEARCH, ISSN 1073-130X, Vol. 70, no 5, p. 1095-1106Article in journal (Refereed)
    Abstract [en]

    The distribution patterns of major and trace elements in sediment cores from the Arctic Ocean, specifically the Yermak Plateau and the Nansen Basin, were evaluated as climate and environmental proxy records of the last 350 ka. The sediments are carbonate

  • 11. Aldahan, A
    et al.
    Sapota, T
    Possnert, Göran
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Ion Physics.
    Rifting, climate and sedimenation in Lake Baikal2009Conference paper (Refereed)
  • 12.
    Aldahan, Ala
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Air and Water Science.
    Alfimov, V.
    Possnert, Göran
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Ion Physics. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy.
    I-129 anthropogenic budget: major sources and sinks2007In: Applied Geochemistry, ISSN 0883-2927, E-ISSN 1872-9134, Vol. 22, no 3, p. 606-618Article in journal (Refereed)
    Abstract [en]

    Data are presented here on the anthropogenic 129I inventory in regions that have been strongly affected by releases from European reprocessing facilities which, to the authors’ knowledge, presently account for >90% of the global isotope source in the Earth’s surface environment. The results show that >90% of the isotope inventory occurs in marine waters with the Nordic Seas and Eurasian basin of the Arctic Ocean containing most of the 129I. Within the terrestrial environment of Europe, soils contain the largest part of the isotope inventory. However, the inventory of the terrestrial system did not provide clues on the most plausible atmospheric source of 129I to Europe, thus supply from both gaseous and marine releases is proposed. The sum of the total inventory in both the marine and terrestrial environments did not match the estimated releases. This imbalance is likely to relate to unconstrained inventory estimates for marine basins (Irish Sea, English Channel and North Sea) close to the facilities, but also to the occurrence of 129I in the biosphere, and possible overestimated releases from the nuclear reprocessing facilities. There is no doubt that the available data on 129I distribution in the environment are far from representative and further research is urgently needed to construct a comprehensive picture.

    Publisher's full text
  • 13.
    Aldahan, Ala
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences. Technology, Department of Engineering Sciences, Ion Physics. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences, Environment and Landscape Dynamics. Miljö- och landskapsdynamik.
    Alfimov, Vasily
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Engineering Sciences. Technology, Department of Engineering Sciences, Ion Physics. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences, Environment and Landscape Dynamics. Jonfysik.
    Kekli, A
    Possnert, Göran
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Engineering Sciences. Technology, Department of Engineering Sciences, Ion Physics. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences, Environment and Landscape Dynamics. jonfysik.
    Cato, Ingemar
    Anthropogenic I-129 in the Baltic Sea2005In: 10th International conference on accelerator mass spectrometry, Berkeley, 2005, p. 33-Conference paper (Refereed)
  • 14.
    Aldahan, Ala
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences. Technology, Department of Engineering Sciences, Ion Physics. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences, Environment and Landscape Dynamics. ELD.
    Alfimov, Vasily
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Engineering Sciences. Technology, Department of Engineering Sciences, Ion Physics. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences, Environment and Landscape Dynamics. Jonfysik.
    Possnert, Göran
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Engineering Sciences. Technology, Department of Engineering Sciences, Ion Physics. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences, Environment and Landscape Dynamics. jonfysik.
    The 129I anthropogenic budget:sources and sinks2005In: Geochimica et cosmochimica Acta, Vol. 69, no 10, p. A716-Article in journal (Refereed)
  • 15.
    Aldahan, Ala
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences.
    Englund, Edvard
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Ion Physics.
    Possnert, Göran
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Ion Physics.
    Cato, Ingemar
    Hou, Xiaolin
    Iodine-129 enrichment in sediment of the Baltic Sea2007In: Applied Geochemistry, ISSN 0883-2927, E-ISSN 1872-9134, Vol. 22, no 3, p. 637-647Article in journal (Refereed)
    Abstract [en]

    Sediments are an excellent archive for evaluation of time-series environmental contamination of water systems. Measurements of ultra-trace radioactive species, such as 129I, provide information for both chronologic calibration and anthropogenic emissions during the nuclear era. Here data are presented on 129I and other chemical parameters from two sediment cores collected in the Baltic Sea during 1997. The sediment sections have a relatively uniform grain size (clay–mud) and cover a period of about 50 a. Distribution of 129I in the sediment strongly relates to the liquid release records from the nuclear reprocessing facilities at Sellafield and La Hague. However, syn- and post-depositional alteration of organic matter at the sediment–water interface and within the sediment column may have contributed to slightly obliterating the anthropogenic 129I signals. Indication of Chernobyl-derived 129I occurs in the sediment profile, but is apparently overridden by the overwhelming flux from the nuclear reprocessing facilities. Although the record did not cover the pre-nuclear era (before 1945) sections, the ultra sensitive 129I profile provides a potential tool for relative dating and monitoring sources of water and sediment to the region.

    Publisher's full text
  • 16.
    Aldahan, Ala
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, LUVAL.
    Hedfors, Jim
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, LUVAL.
    Possnert, Göran
    Uppsala University, Disciplinary Domain of Science and Technology, För teknisk-naturvetenskapliga fakulteten gemensamma enheter, Tandem Laboratory. Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Ion Physics.
    Kulan, Abdulhadi
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, LUVAL.
    Berggren, Ann-Marie
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, LUVAL.
    Söderström, C.
    FOI, Swedish Defence Research Agency, Stockholm, Sweden.
    Atmospheric impact on beryllium isotopes as solar activity proxy2008In: Geophysical Research Letters, ISSN 0094-8276, E-ISSN 1944-8007, Vol. 35, no L21812Article in journal (Refereed)
    Abstract [en]

    Reconstructing solar activity variability beyond the time scale of actual measurements provides invaluable data for modeling of past and future climate change. The 10 Be isotope has been a primary proxy archive of past solar activity and cosmic ray intensity, particularly for the last millennium. There is, however, a lack of direct high-resolution atmospheric time series on 10 Be that enable estimating atmospheric modulation on the production signal. Here we report quasi-weekly data on 10 Be and 7 Be isotopes covering the periods 1983-2000 and 1975-2006 respectively, that show, for the first time, coherent variations reflecting both atmospheric and production effects. Our data indicate intrusion of stratosphere/upper troposphere air masses that can modulate the isotopes production signal, and may induce relative peaks in the natural 10 Be archives (i.e., ice and sediment). The atmospheric impact on the Be-isotopes can disturb the production signals and consequently the estimate of past solar activity magnitude. Citation: Aldahan, A., J. Hedfors, G. Possnert, A. Kulan, A.-M. Berggren, and C. Soderstrom (2008), Atmospheric impact on beryllium isotopes as solar activity proxy, Geophys. Res. Lett., 35, L21812, doi: 10.1029/2008GL035189.

    Publisher's full text
  • 17.
    Aldahan, Ala
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Ion Physics. miljö-och landskapsdynamik.
    Kekli, A
    Possnert, Göran
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Ion Physics. jonfysik.
    Distribution of 129I in rivers of the Baltic region2006In: Jour. Envir. Radioactivity, Vol. 88, p. 49-73Article in journal (Refereed)
  • 18.
    Aldahan, Ala
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences.
    Persson, S
    Uppsala University, Disciplinary Domain of Science and Technology, För teknisk-naturvetenskapliga fakulteten gemensamma enheter, Tandem Laboratory.
    Possnert, Göran
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Ion Physics.
    Hou, Xiaolin
    Distribution of I-127 and I-129 in preciptitation at high European latitudes2009In: Geophysical Research Letters, ISSN 0094-8276, E-ISSN 1944-8007, Vol. 36, p. L11805-Article in journal (Refereed)
    Abstract [en]

     We here present the most extensive data set on the distribution of   I-127 and I-129 in precipitation (rain and snow) covering the period   2000-2006 and European latitudes 55 degrees N-68 degrees N. Our results   indicate a wide variation in the concentrations and fluxes of the two   isotopes associated with generally higher values at near coastal sites   compared to the inland ones. Total wet-related annual deposition of   I-127 and I-129 on Sweden and Denmark is estimated at about 1.2 x 10(9)   g and 60 g respectively. The average annual I-129 wet deposition   accounts for <1% and <0.05% of the total annual gaseous and liquid,   respectively, discharges from the Sellafiled and La Hague Facilities.   The I-127 annual wet deposition represents < 1% of the estimated global   oceanic iodine flux. Air mass trajectories suggest that events of   enhanced I-129 in precipitation are closely related to southwesterly weather fronts from regions of elevated concentrations.

    Publisher's full text
  • 19. Aldahan, Ala
    et al.
    Persson, S
    Possnert, Göran
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Ion Physics.
    Hou, Xiaolin
    Seven years record of I-127 and I-129 in precipitation2009In: Geochimica et Cosmochimica Acta, ISSN 0016-7037, E-ISSN 1872-9533, Vol. 73, no 13/suppl 1, p. A23-A23Article in journal (Refereed)
  • 20.
    Aldahan, Ala
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences. Technology, Department of Engineering Sciences, Ion Physics. ELD.
    Possnert, Göran
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Engineering Sciences. Technology, Department of Engineering Sciences, Ion Physics. Jonfysik.
    Geomagnetic and climatic variability reflected by 10Be during the Quaternary and Late Pliocene2003In: Geophysical Research Letters, Vol. 30, no 6, p. 10.1029/2002GL016077-Article in journal (Refereed)
  • 21.
    Aldahan, Ala
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences.
    Possnert, Göran
    Uppsala University, Disciplinary Domain of Science and Technology, För teknisk-naturvetenskapliga fakulteten gemensamma enheter, Tandem Laboratory.
    Alfimov, V.
    Cato, I.
    Sveriges geologiska undersökning.
    Kekli, Aziz
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences.
    Anthropogenic I-129 in the Baltic Sea2007In: 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. 491-495Article in journal (Refereed)
    Abstract [en]

    We report here data on the distribution of I-129 in water of the Baltic Sea and Skagerrak-Kattegat basins obtained through sampling campaigns during the years 2000 and 2001. I-129 in the water of the Skagerrak-Kattegat shows persistently high concentrations in both the surface and deep parts. A decreasing trend in surface water I-129 concentration is observed away from the Kattegat basin and into the Baltic Sea. Inventory calculations indicate that at least 95%of the isotope supply to the Baltic Sea is from the North Sea marine water via Skagerrak-Kattegat and only minor part is from riverine inflow and the Chernobyl accident. As the discharges from the nuclear reprocessing facilities were not decreased during the last decade, it is expected that more I-129 will accumulate in the Baltic Sea and related basins in the future. Consequently, systematic sampling is needed to reevaluate the concentration levels not only in the water, but also in the sediments and biota of the region.

    Publisher's full text
  • 22.
    Aldahan, Ala
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences. ELD.
    Possnert, Göran
    Technology, Department of Materials Science. jonfysik.
    Buraglio, N
    Steffensen, J
    129I isotope in an ice core from Greenland2000In: 6th International conference on Acid Rain, 10-16 December, Tsukuba, Japan, 2000, p. 122-Conference paper (Refereed)
  • 23.
    Aldahan, Ala
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, LUVAL.
    Possnert, Göran
    Uppsala University, Disciplinary Domain of Science and Technology, För teknisk-naturvetenskapliga fakulteten gemensamma enheter, Tandem Laboratory.
    El Saiy, A.
    Abdelghany, O.
    Particle-bound Be-10 from a low latitude arid region2014In: Journal of Radioanalytical and Nuclear Chemistry, ISSN 0236-5731, E-ISSN 1588-2780, Vol. 299, no 3, p. 1709-1713Article in journal (Refereed)
    Abstract [en]

    The Be-10 isotope is widely used in geochronology, climate and environmental analyses and astrophysics where atmospheric deposition model estimate plays a vital role for the initial concentration. Data from arid regions have not been well constrained because of sparse measurement and here we present Be-10 concentration in samples of dust, soil, marine sediments and paleosol collected from an arid to semi-arid low latitude region. These results indicate concentrations that are about a factor of three lower than values expected from latitude zonal models, but are comparable with global atmospheric depositional model. The agreement and discrepancy between model and measured data are rather vital for establishing accurate initial Be-10 in the Earth's surface environment for reconstruction of paleoclimatic variability (precipitation rates and temperature).