Looking at Japanese wind forecasts to give more details of the predicted local conditions, the winds are anticipated to be highly variable through early Monday morning Japan Standard Time (JST). The maps below show forecast wind direction and speed in meters per second (1 m/s is 2.2 mph). Small-scale circulations are capable of spreading any possible radiation leaks over areas inland. Late in the day Sunday (JST) transport pathways are toward the northwest, shifting to more southeastward (toward Tokyo metropolitan area) as the evening progresses. Efforts to contain the reactor leakage are continuingand hopefully significant progress can be made before these shifting winds dominate. There continues to be much uncertainty in the nature of the source term – i.e., the composition, magnitude, and timing of the radiation releases. This renders the prediction of dosage levels very challenging. Here is a story in Science magazine on the associated difficulties in long-range plume prediction.
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