Numerical experiment for strontium-90 and cesium-137 in the Japan Sea

Hideyuki Kawamura, Toshimichi Ito, Takuya Kobayashi, Shigeyoshi Otosaka, Naoki Hirose, Orihiko Togawa

    Research output: Contribution to journalArticle

    3 Citations (Scopus)

    Abstract

    A numerical experiment is carried out to reproduce distribution of concentration of 90Sr and 137Cs, estimate their total amount and verify their source in the Japan Sea. Model results are in good agreement with observational findings in the Japan Sea expeditions between 1997 and 2002 by the Japan Atomic Energy Agency. Vertical profiles of the concentration of 90Sr and 137Cs show exponential decreases with depth from the sea surface to the sea bottom. From the model and observational results, it is suggested that the concentration of 90Sr and 137Cs in the surface layer is approximately in the range of 1.0-1.5 Bq/m3 and 2.0-2.5 Bq/m3, respectively. On the other hand, it is found that the concentration in the intermediate and deep layer is higher than that observed in the northwestern Pacific Ocean, suggesting active winter convection in the Japan Sea. The total amount of 90Sr and 137Cs in the seawater is evaluated to be 1.34 × 1015 Bq and 2.02 × 1015 Bq, respectively, in the numerical experiment, which demonstrates an estimation by observational data obtained in the Japan Sea expeditions. The total amount of 90Sr and 137Cs changed during the second half of 20th century corresponding to deposition at the sea surface with the maximums of 4.86 × 1015 Bq for 90Sr and 7.33 × 1015 Bq for 137Cs, respectively, in the mid-1960s. The numerical experiment suggests that the main source of 90Sr and 137Cs has been global fallout, although there have been some potential sources in the Japan Sea.

    Original languageEnglish
    Pages (from-to)649-662
    Number of pages14
    JournalJournal of Oceanography
    Volume66
    Issue number5
    DOIs
    Publication statusPublished - Sep 24 2010

    Fingerprint

    cesium isotope
    strontium isotope
    sea surface
    experiment
    fallout
    vertical profile
    surface layer
    convection
    seawater
    winter
    ocean
    energy
    sea

    All Science Journal Classification (ASJC) codes

    • Oceanography

    Cite this

    Numerical experiment for strontium-90 and cesium-137 in the Japan Sea. / Kawamura, Hideyuki; Ito, Toshimichi; Kobayashi, Takuya; Otosaka, Shigeyoshi; Hirose, Naoki; Togawa, Orihiko.

    In: Journal of Oceanography, Vol. 66, No. 5, 24.09.2010, p. 649-662.

    Research output: Contribution to journalArticle

    Kawamura, H, Ito, T, Kobayashi, T, Otosaka, S, Hirose, N & Togawa, O 2010, 'Numerical experiment for strontium-90 and cesium-137 in the Japan Sea', Journal of Oceanography, vol. 66, no. 5, pp. 649-662. https://doi.org/10.1007/s10872-010-0053-5
    Kawamura, Hideyuki ; Ito, Toshimichi ; Kobayashi, Takuya ; Otosaka, Shigeyoshi ; Hirose, Naoki ; Togawa, Orihiko. / Numerical experiment for strontium-90 and cesium-137 in the Japan Sea. In: Journal of Oceanography. 2010 ; Vol. 66, No. 5. pp. 649-662.
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