Published: March 16th, 2011 at 2:03 pm ET
Please note: Simulated forecasts only account for single release events, not a combination of all radioactive releases
Simulation of release from March 12 explosion at Fukushima Daiichi No. 1, Belgium Institute for Space Aeronomy, March 15:
Simulation of release from March 14 explosion at Fukushima Daiichi No. 3, Belgium Institute for Space Aeronomy, March 15:
Simulation of release from March 14 explosion at Fukushima Daiichi No. 3, Belgium Institute for Space Aeronomy, March 16:
New simulation of the cloud of radioactive pollution in Japan, Institute for Space Aeronomy (Belgium), March 16, 2011:
The IASB has released a new simulation of the dispersion of the cloud of radioactive pollution emitted by the explosion in Daiichi Building-3 nuclear power plant in Fukushima (Monday, 6:47 GMT). This simulation is one of the first to take into account the leaching by rain as the cloud on the route. This results in a much faster decrease of the concentration of particulate pollutants. Based on these projections (which extend up to this Saturday), the cloud will disappear before they reach U.S. shores.
This simulation is based on the hypothetical initial cloud between 0 and 1500 m altitude. We tested the sensitivity to this assumption with another simulation where the initial cloud rises up to 3000 m. Thanks to leaching by rainfall, the result is almost the same: the cloud of radioactive pollution disappears over the Pacific Ocean.
On the other hand, an explosion has occurred in the reactor Daiichi-2 last night at 2110 GMT. Given the paucity of information on this, we are not able to produce a useful simulation of the event. [Emphasis Added]
For details on these simulations, see press release dated March 15, 2011
New simulation of the cloud of radioactive pollution in Japan, Institute for Space Aeronomy (Belgium), March 15, 2011:
Two explosions occurred on Saturday 12 March and Monday, March 14, 2011 in the reactor buildings and Daiichi1 Daiichi3 nuclear power plant in Fukushima (Japan). Each of these explosions sent a plume of radioactive pollution in the atmosphere.
Researchers from the IASB (Institut d’Aeronomie Spatiale de Belgique) used a dispersion model to simulate the transport of polluted air masses until Friday, March 18. The simulations take into account the natural dilution of the clouds As they are transported.
These two simulations place a large number of particles in a “box” located above the powerhouse, and then calculate the dispersion of the initial cloud. The initial height of the box is an essential criterion: the higher it is, more particles will go far. Based on the available videos, the researchers chose a maximum height of 500 m and 1500m for Daaichi1 Daaichi3, which seems much more energetic explosion. It should be noted that these choices are arbitrary.
The model indicates that the two plumes stay only briefly along the coast in the immediate vicinity of the plant. They are then transported to the North East over the Pacific Ocean where they could pollute both the Kamchatka Peninsula (Russia). In particular, the plume caused by the explosion of Daiichi3 (which occurred on Monday morning), should be extended on Tuesday in a filament end remarkably over the Pacific Ocean. But it * could * touch the Tokyo area, but the model resolution does not say that.
We use the dispersion model FLEXPART Developed by the Norwegian Institute for Air Research. It is driven by the weather forecast national service weather in the United States. Several simplifications or limitations should be noted:
The weather forecasts are used to a fairly low resolution (“pixels” of about 100km by 100km). Our simulations are only valid for long distances. They do not predict the contamination of areas near the bomb site.
These simulations take into account the dilution of the cloud, but not its leaching by precipitation (rain) encountered on his way.
The injection time of the cloud particles was arbitrarily set: 20 minutes Daaichi1 (ie d of 6.40 am to 7 am, Greenwich Mean Time, 12.03.2011) and 14 minutes Daaichi3.
The height of particle injection, as stated above, is chosen quite arbitrarily on the basis of available videos. These heights were selected for 500m and 1500m for Daaichi1 Daaichi3.
BIRA-IASB is of course available for further explanation.
Published: March 16th, 2011 at 2:03 pm ET