Riding the jet stream, radioactive materials released from the Fukushima No. 1 nuclear power plant crossed North America and arrived in Switzerland in less than 10 days, according to researchers.
Riding the jet stream, radioactive materials released from the Fukushima No. 1 nuclear power plant crossed North America and arrived in Switzerland in less than 10 days, according to researchers.
The modeling simulation was done by a team of researchers from Kyushu University and the University of Tokyo. The results confirmed timings and concentrations observed in Europe and North America.
Toshihiko Takemura, associate professor of meteorology at Kyushu University's Research Institute for Applied Mechanics and colleagues analyzed the weather conditions after March 14-16, when large amounts of radioactive materials were apparently discharged following a succession of hydrogen explosions at the plant operated by Tokyo Electric Power Co.
Ascending currents caused by an atmospheric depression that was passing over east Japan lifted particulates, which were carried by the 108 kph westerlies, blowing more than 5,000 meters above ground, and traveled 9,000 kilometers in about three days to North America's West Coast, according to the simulation.
When the cloud hit the West Coast its radioactivity level had fallen to about one 100 millionth of what was observed near the Fukushima No. 1 plant--an amount that would have no impact on human health, the research group said.
After crossing North America into skies above the Atlantic, the particulates rode the westerlies that changed directions northward and hit Iceland on March 20. The cloud of particulates then headed south to cover all of Europe, and was detected in Switzerland on March 23 local time.