The dispersion of 99Tc in the Nordic Seas and the Arctic Ocean: a comparison of model results and observations

Kärcher, Michael; Gerland, Sebastian; Harms, I.; Iøsjpe, M.; Heldal, Hilde Elise; Kershaw, P. J.; Sickel, M.

doi:10.1016/j.jenvrad.2004.01.026

Cited by 68 publications

(35 citation statements)

References 23 publications

(33 reference statements)

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“…For northern Norway, data from surface water observations at Hillesøy and NAOSIM results show good agreement. The same holds for the surface concentrations further upstream in the NCC and in the North Sea between 1996 and 1999 (Karcher et al, 2003a).…”

Section: Discussionsupporting

confidence: 58%

“…This difference in levels and results from oceanographic 3-D modelling (Karcher et al, 2003a) give reasons to link the enhanced discharges from the nuclear reprocessing plant at Sellafield to the 99 Tc level changes observed in the Arctic. However, levels measured at Hillesøy on the coast of northern Norway, also in 2000 , are again five times higher than in Kongsfjorden at the same time.…”

Section: Discussionmentioning

confidence: 95%

“…3) indicate large changes in the vertical distribution of 99 Tc in the ocean west of Svalbard over a relatively short time. Reasons may be a strong seasonal variability in the upper part of the WSC intensity or a strong month-to-month variability of surface concentrations as observed and simulated in the NCC further upstream (Karcher et al, 2003a). Unfortunately, corresponding NAOSIM model simulations later than 1999 are not yet available and a direct comparison of the observed levels and the model is not possible at this stage.…”

Section: Discussionmentioning

confidence: 99%

“…Furthermore, as a result of enhanced international collaboration, data obtained from institutions from different nations is becoming more commonly available and integrated due to improved communication and database possibilities (e.g. AMAP, 2002, Karcher et al, 2003a.…”

Section: Discussionmentioning

confidence: 99%

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99Tc in seawater in the West Spitsbergen Current and adjacent areas

Gerland

Lind

Dowdall

et al. 2003

Journal of Environmental Radioactivity

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99Tc levels were measured in seawater samples collected between 2000 and 2002 in the West Spitsbergen Current (WSC) and along the western coast of Svalbard or Spitzbergen and compared with available oceanographic 3-D modelling results for the late 1990s. Additional data from related regions are also presented in order to support the data interpretation. The seawater in the Arctic fjord Kongsfjorden on the western coast of Svalbard is influenced by the WSC, as shown by the 99 Tc levels in surface water. By means of the WSC, 99 Tc reaches the Eastern Fram Strait, where one branch of the WSC turns west into the East Greenland Current (EGC), and another branch continues northwards into the Arctic Ocean. Surface seawater collected in the central part of the WSC during a cruise on board the R/V "Polarstern" in the summer of 2000, showed higher levels of 99 Tc than samples measured in Kongsfjorden in the spring of 2000. However, all levels measured in surface water are of the same order of magnitude. Data from sampling of deeper water in the WSC and EGC provide information pertaining to the lateral distribution of 99 Tc. In all vertical profiling surveys (conducted in spring and summer), the highest levels of 99 Tc were found in surface water. Comparison with oceanographic 3-D modelling indicates both significant seasonal variations in the lateral stratification of the WSC and variations with depth over shorter vertical distances. This information can be applied in sampling strategies, environmental monitoring, long-range transport of pollutants and physical oceanography.

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Section: Discussionsupporting

confidence: 58%

Section: Discussionmentioning

confidence: 95%

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

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99Tc in seawater in the West Spitsbergen Current and adjacent areas

Gerland

Lind

Dowdall

et al. 2003

Journal of Environmental Radioactivity

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“…In a pioneering work by Prandle (1984), mixing and time-scales of the radionuclide 137 Cs on the European continental shelf was investigated. More recently, it has been shown that the current generation of OGCMs are capable of simulating the large-scale dispersion (Nordic Seas and the Arctic Ocean) of radionuclides from both European reprocessing plants and atmospheric fallout from nuclear bomb testing in a realistic manner (e.g., Karcher et al, 2004;Gao et al, 2004).…”

Section: Introductionmentioning

confidence: 99%

Diagnosing ocean tracer transport from Sellafield and Dounreay by equivalent diffusion and age

et al. 2008

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A simple approach for estimating the equivalent diffusion for diagnosing tracer transport is proposed. Two different expressions are derived; one is based directly on an analytical solution of the two-dimensional advection-diffusion equation, the other uses the variance of the tracer distribution. To illustrate some features of the equivalent diffusion and possible applications thereof, idealized releases of passive tracers from the nuclear fuel reprocessing plants at Sellafield in the Irish Sea and Dounreay on the northern coast of Scotland have been simulated with a regional isopycnic co-ordinate Ocean General Circulation Model. Both continuous and pulse releases are considered; the former being representative of the actual historical discharges from the reprocessing plants, the latter resembling an accidental scenario. Age tracers are included to calculate the mean time elapsed since the tracers left their source regions. It is found that in the Nordic Seas the age of tracers from Dounreay is approximately 2 years younger than the age from Sellafield. Although tracers from both sources eventually end up along the same transport routes, significant qualitative differences regarding the dispersion properties are found. It is argued that one single parameter, the equivalent horizontal diffusion, which is estimated to be in the range of 20-56 m 2 s −1 from Sellafield and 170-485 m 2 s −1 from Dounreay, determines these differences.

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A tlantic O cean: Radionuclides

Kershaw

2005

Encyclopedia of Inorganic Chemistry

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This article summarizes the main sources and the fate of radionuclides in the Atlantic Ocean, resulting primarily from human activity. This covers direct and indirect sources of artificial radionuclides due to global fallout from weapons testing, controlled releases from nuclear establishments, the deliberate disposal of radioactive waste, accidental inputs, and the presence of naturally occurring radionuclides, sometimes in enhanced quantities due to human activities. The distribution and behavior of radionuclides in seawater, sediments, and biota are described, being a consequence of both the nature of the source term and the fundamental properties of the radionuclides (chemical behavior, half‐life). Finally, the article considers the radiological consequences due to the principal sources responsible for the maximum dose to the human population: nuclear fuel reprocessing and naturally occurring radionuclides.

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The dispersion of 99Tc in the Nordic Seas and the Arctic Ocean: a comparison of model results and observations

Cited by 68 publications

References 23 publications

99Tc in seawater in the West Spitsbergen Current and adjacent areas

99Tc in seawater in the West Spitsbergen Current and adjacent areas

Diagnosing ocean tracer transport from Sellafield and Dounreay by equivalent diffusion and age

A tlantic O cean: Radionuclides

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