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| Titel |
Initial spread of 137Cs from the Fukushima Dai-ichi Nuclear Power Plant over the Japan continental shelf: a study using a high-resolution, global-coastal nested ocean model |
| VerfasserIn |
Z. Lai, C. Chen, R. Beardsley, H. Lin, R. Ji, J. Sasaki, J. Lin |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1726-4170
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| Digitales Dokument |
URL |
| Erschienen |
In: Biogeosciences ; 10, no. 8 ; Nr. 10, no. 8 (2013-08-14), S.5439-5449 |
| Datensatznummer |
250085295
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| Publikation (Nr.) |
 copernicus.org/bg-10-5439-2013.pdf |
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| Zusammenfassung |
| The 11 March 2011 tsunami triggered by the M9 and M7.9 earthquakes
off the Tōhoku coast destroyed
facilities at the Fukushima Dai-ichi Nuclear Power Plant (FNPP) leading to a
significant long-term flow of the radionuclide 137Cs into coastal
waters. A high-resolution, global-coastal nested ocean model was first
constructed to simulate the 11 March tsunami and coastal inundation. Based on
the model's success in reproducing the observed tsunami and coastal
inundation, model experiments were then conducted with differing grid
resolution to assess the initial spread of 137Cs over the eastern shelf
of Japan. The 137Cs was tracked as a conservative tracer (without
radioactive decay) in the three-dimensional model flow field over the period
of 26 March–31 August 2011. The results clearly show that for the same
137Cs discharge, the model-predicted spreading of 137Cs was
sensitive not only to model resolution but also the FNPP seawall structure. A
coarse-resolution (∼2 km) model simulation led to an overestimation
of lateral diffusion and thus faster dispersion of 137Cs from the coast
to the deep ocean, while advective processes played a more significant role
when the model resolution at and around the FNPP was refined to ∼5 m.
By resolving the pathways from the leaking source to the southern and
northern discharge canals, the high-resolution model better predicted the
137Cs spreading in the inner shelf where in situ measurements were made
at 30 km off the coast. The overestimation of 137Cs concentration near
the coast is thought to be due to the omission of sedimentation and
biogeochemical processes as well as uncertainties in the amount of 137Cs
leaking from the source in the model. As a result, a biogeochemical module
should be included in the model for more realistic simulations of the fate
and spreading of 137Cs in the ocean. |
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