EURAD: "The observational data of the CTBTO now show a clear decrease of the worldwide radioactive concentrations outside of Japan. Therefore we now do not continue with the predictions for the northern hemisphere."

Potential dispersion of the radioactive cloud over The Northern Hemisphere

This animation displays a potential dispersion of the radioactive cloud (Caesium 137 Isotope) after a nuclear accident in reactor Fukushima I. The continuous release rate is very uncertain, thus the calculations have to be interpreted qualitatively. Dispersion in the near surface level (Level 1), in appr. 2500 m height (Level 12) and in appr. 5000 m height (Level 16).

Source: EURAD