Influence of the diagnostic wind field model on the results of calculation of the microscale atmospheric dispersion in moderately complex terrain

The impact of diagnostic wind field model on the results of calculation of microscale atmospheric dispersion in moderately complex terrain conditions was investigated. The extensive radiological and meteorological data set collected at the site of the research reactor of the Chalk River Laboratories (CRL) in Canada had been compared with the results of calculations of the Local Scale Model Chain of the EU nuclear emergency response system JRODOS. The diagnostic wind field model based on divergence minimizing procedure and the atmospheric dispersion model RIMPUFF were used in calculations. Taking into account complex topography features with the use of diagnostic wind field model improved the results of calculations. For certain months, the level of improvement of the normalized mean squared error reached the factor of 2. For the whole simulation period (January-July, 2007) the level of improvement by taking into account terrain features with the diagnostic wind field model was about 9%. The use of diagnostic wind field model also significantly improved the fractional bias of the calculated results. Physical analysis of the selected cases of atmospheric dispersion at the CRL site had been performed.