Initial spread of &amp;lt;sup&amp;gt;137&amp;lt;/sup&amp;gt;Cs from the Fukushima Dai-ichi Nuclear Power Plant over the Japan continental shelf: a study using a high-resolution, global-coastal nested ocean model

Lai, Zhigang; Chen, Changsheng; Beardsley, Robert C.; Lin, Huichan; Ji, Rubao; Sasaki, Jun; Lin, Jian

doi:10.5194/bg-10-5439-2013

Cited by 15 publications

(10 citation statements)

References 23 publications

(44 reference statements)

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“…The agreement of the magnitude of the 137 Cs signal in the model simulations with the experimental results on Line P (Fig. 3) is consistent with the latter estimates (21,22) of the Fukushima inputs.…”

Section: Discussionsupporting

confidence: 86%

Arrival of the Fukushima radioactivity plume in North American continental waters

Smith

Brown

Williams

et al. 2014

Proc. Natl. Acad. Sci. U.S.A.

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The large discharge of radioactivity into the northwest Pacific Ocean from the 2011 Fukushima Dai-ichi nuclear reactor accident has generated considerable concern about the spread of this material across the ocean to North America. We report here the first systematic study to our knowledge of the transport of the Fukushima marine radioactivity signal to the eastern North Pacific. Time series measurements of 134Cs and 137Cs in seawater revealed the initial arrival of the Fukushima signal by ocean current transport at a location 1,500 km west of British Columbia, Canada, in June 2012, about 1.3 y after the accident. By June 2013, the Fukushima signal had spread onto the Canadian continental shelf, and by February 2014, it had increased to a value of 2 Bq/m3 throughout the upper 150 m of the water column, resulting in an overall doubling of the fallout background from atmospheric nuclear weapons tests. Ocean circulation model estimates that are in reasonable agreement with our measured values indicate that future total levels of 137Cs (Fukushima-derived plus fallout 137Cs) off the North American coast will likely attain maximum values in the 3–5 Bq/m3 range by 2015–2016 before declining to levels closer to the fallout background of about 1 Bq/m3 by 2021. The increase in 137Cs levels in the eastern North Pacific from Fukushima inputs will probably return eastern North Pacific concentrations to the fallout levels that prevailed during the 1980s but does not represent a threat to human health or the environment.

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Section: Discussionsupporting

confidence: 86%

Arrival of the Fukushima radioactivity plume in North American continental waters

Smith

Brown

Williams

et al. 2014

Proc. Natl. Acad. Sci. U.S.A.

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“…The finite-volume approach ensures the conservation of mass, heat, salt, and tracer concentrations in the sense of numerical computation. The latest version of FVCOM (v3.1.6) used in this study is a fully coupled currentwave-sediment-ice model with multiple options for domain nesting, flooding/drying processes, and hydrostatic/non-hydrostatic solvers (Chen et al, 2013). The wet/dry treatment algorithm used to simulate the coastal inundation is described in appendix A.…”

Section: The Integrated Model System and Experiments Designmentioning

confidence: 99%

“…After the initial simulation of the March 11 tsunami and coastal inundation, this model could then be used to track the initial spread of radionuclides (esp. Cs-137; half-life ~30 years) from the FDNPP into and across the shelf (Lai et al, 2013). To our knowledge, simulating tsunami waves using a 3-D stratified ocean model has not been tried in the past.…”

Section: Introductionmentioning

confidence: 99%

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The March 11, 2011 Tōhoku M9.0 earthquake-induced tsunami and coastal inundation along the Japanese coast: A model assessment

Chen

Lai

Beardsley

et al. 2014

Progress in Oceanography

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A high-resolution nested global-Japan coastal FVCOM system was used to simulate the March 11, Tōhoku M9 earthquake-induced tsunami waves and coastal inundation along the northeastern coast of Honshu Island in the western Pacific Ocean. Experiments were made with initial fields provided by five seismic rupture models under realistic conditions with inclusion of the Kuroshio, tides and wind forcing. Results show that the model-computed intensities and distributions of tsunami waves and subsequent coastal inundation could be significantly influenced by initial conditions, even though all five cases were capable of reproducing key features of the tsunami waves. Modeled tsunami waves featured a low dispersive, weakly nonlinear long wave controlled by hydrostatic dynamics. Non-hydrostatic effects only became significant when tsunami waves reached the inner shelf and the amplitude of the leading tsunami wave grew within O(1) of the local water depth (10 m or shallower). In both hydrostatic and nonhydrostatic cases, significant mixing occurred when the ratio of wave amplitude to local water depth grew to about 0.25 or greater. Model-predicted run-up was in good agreement with 2-D Nwave analytical solutions on the northern coast around South Iwate where inundation was small, but not in the central Sendai coastal region where inundation was large and 3-D wave dynamics became significant. The experiments suggest that once local bathymetry is accurately configured and the intensity and shape of the initial bottom movement can be predicted, this nested FVCOM system is capable of making accurate predictions of tsunami waves and coastal inundation.

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“…With a 50 year spin‐up, Global‐FVCOM has been run under realistic forcing conditions for the 35 year period 1978–2012. The model results were and are being validated in the Arctic, northwest Atlantic Ocean shelf regions, and other regions [e.g., Chen et al ., ; Gao et al ., ; Chen et al ., ; Hu et al ., ; Lai et al ., ]. To identify and quantify the physical driving mechanism for the summertime circulation in the Gulf of Tonkin, we reran Global‐FVCOM for 1988–1989 by turning off or on stratification, tides, Hong River discharge, winds, and surface heat flux.…”

Section: Field Data and Modelmentioning

confidence: 99%

Observational and model studies of the circulation in the Gulf of Tonkin, South China Sea

et al. 2013

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[1] Moored current measurements were made at one mooring site in the northern Gulf of Tonkin for about 1 year during [1988][1989]. Analyses were performed to examine characteristics and variability of tidal and subtidal flows. Rotary spectra showed two peaks at diurnal and semidiurnal periods, with higher diurnal energy. Complex demodulations of diurnal and semidiurnal tidal currents indicated that the tidal current magnitudes varied significantly with seasons: more energetic in the stratified summer than in the vertically well-mixed winter. The observed subtidal currents were highly correlated with the surface wind in winter but not in summer; challenging the conceptual summertime anticyclonic circulation pattern derived using wind-driven homogenous circulation theory. The computed currents from a global ocean model were in good agreement with the observed currents. Similar to the current observations, the model-computed flow patterns were consistent with the conceptual wind-driven circulation pattern in winter but opposite in summer. Process-oriented experiments suggest that the summertime cyclonic circulation in the northern Gulf of Tonkin forms as a result of the combination of stratified wind-driven circulation and tidal-rectified inflow from Qiongzhou Strait. The interaction between the southwest monsoon and buoyancy-driven flow from Hong River can significantly intensify the cyclonic circulation near the surface, but its contribution to the vertically averaged flow of the cyclonic circulation is limited.

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Initial spread of <sup>137</sup>Cs from the Fukushima Dai-ichi Nuclear Power Plant over the Japan continental shelf: a study using a high-resolution, global-coastal nested ocean model

Cited by 15 publications

References 23 publications

Arrival of the Fukushima radioactivity plume in North American continental waters

Arrival of the Fukushima radioactivity plume in North American continental waters

The March 11, 2011 Tōhoku M9.0 earthquake-induced tsunami and coastal inundation along the Japanese coast: A model assessment

Observational and model studies of the circulation in the Gulf of Tonkin, South China Sea

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