Simulation Map of Cesium-137 Deposition Across the Pacific by CEREA Shows Contamination in US Greater Than That of Western Japan

France's CEREA has the simulation map of ground deposition of cesium-137 from the Fukushima I Nuclear Power Plant accident on its "Fukushima" page. It not only shows Japan but also the entire northern Pacific Rim, from Russian Siberia to Alaska to the West Coast of the US to the entire US.

According to the map, the US, particularly the West Coast and particularly California, may be more contaminated with radioactive cesium than the western half of Japan or Hokkaido. It looks more contaminated than South Korea or China. Canada doesn't look too well either, particularly along the border with US on the western half.

From CEREA's Fukushima page:

Atmospheric dispersion of radionuclides from the Fukushima-Daichii nuclear power plant

CEREA, joint laboratory École des Ponts ParisTech and EdF R&D
Victor Winiarek, Marc Bocquet, Yelva Roustan, Camille Birman, Pierre Tran

Map of ground deposition of caesium-137 for the Fukushima-Daichii accident.

The simulation was performed with a specific version of the numerical atmospheric chemistry and transport model Polyphemus/Polair3D. The parametrisations used for the transport and physical removal of the radionuclides are described in [1,2,3,4].

The magnitude of the deposition field is uncertain and the simulated values of deposited radionuclides could be significantly different from the actual deposition. In particular, the source term remains uncertain. Therefore, these results should be seen as preliminary and they are likely to be revised as new information become available to better constrain the source term and when radionuclides data can be used to evaluate the model simulation results.

The page also has the animated simulation of cesium-137 dispersion from March 11 to April 6, 2011. If the Japanese think they are the only ones who have the radiation and radioactive fallout from the accident, they are very much mistaken, if the simulation is accurate. (Meteorological institutes and bureaus in Austria, Germany, and Norway all had similar simulation maps.)

Radioactive materials spewed out of Fukushima I Nuke Plant went up and away on the jet stream, reaching the other side of the Pacific. When the fallout from explosions (March 14, 15) reached the US West Coast, it came with an unusually heavy rainfall in California.

CEREA's description of the animation (if the animation doesn't work, or if you want to see the bigger one, go to CEREA's page):

Movie of the Fukushima-Daichii activity in the air (caesium-137, ground level)

The simulation was performed with a specific version of the numerical atmospheric chemistry and transport model Polyphemus/Polair3D. The parametrisations used for the transport and physical removal of the radionuclides are described in [1,2,3,4].

The magnitude of activity concentration field is uncertain and could be significantly different from the actual one. In particular, the source term remains uncertain. Therefore, these results should be seen as preliminary and they are likely to be revised as new information become available to better constrain the source term and when radionuclides data can be used to evaluate the model simulation results.

(Go to their page to see the references.)

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