Hirohiko Ishikawa

Experimental verification study for system for prediction of environmental emergency dose information: SPEEDI (I): three-dimensional interpolation method for surface wind observations in complex terrain to produce gridded wind field

Modele mathematique representant les flux dair autour dun site nucleaire permettant de predire le devenir deventuels rejets deffluents gazeux

Development of Regionally Extended Worldwide Version of System for Prediction of Environmental Emergency Dose Information: WSPEEDI, (II): Long-Range Transport Model and Its Application to Dispersion of Cesium-137 from Chernobyl

As a part of a study to expand the computational region of SPEEDI (System for Prediction of Environmental Emergency Dose Information), a long-range atmospheric transport model of radioactivity was developed. This model computes air concentration, deposition, external γ-dose and internal dose due to inhalation. The model is applied to the simulation of dispersion of 317Cs from Chernobyl over Europe and the calculated values of surface air concentrations and deposition were compared with those of measurements. In the comparison of surface air concentration, about half of the calculated value agreed with measured ones within an order. The degree of quantitative agreement was comparable to that of the model application for the dispersion in local complex terrain. This suggests that the proposed model has capability to assess the long-range transport and the consequence of radioactivity released into the atmosphere.

Development of Worldwide Version of System for Prediction of Environmental Emergency Dose Information: WSPEEDI, (III): Revised Numerical Models, Integrated Software Environment and Verification

The numerical models of WSPEEDI (Worldwide version of System for Prediction of Environmental Emergency Dose Information) were revised. The new models are formulated with a terrain following vertical coordinates with the compressibility of the atmosphere being considered. The models have been integrated into a computer code system together with system control software, worldwide geographic database, meteorological data pre-processor and graphics. The performance of the code system has been evaluated against the Chernobyl case with reliable source terms, well established meteorological input and a comprehensive monitoring database, which were provided in ATMES (Atmospheric Transport Model Evaluation Study) coordinated by IAEA, WMO and CEC.