Development and verification of long-range atmospheric transport model of radon-222 and lead-210 including scavenging process

A three-dimensional Eulerian atmospheric long-range transport model of radon-222 (Rn-222) and lead-210 (Pb-210) coupled with meteorological model MM5 was developed. The model calculates advection, diffusion, radiation decay and deposition processes in a horizontal scale of several thousand kilometers. This model was applied to East Asia. Performance of the model was evaluated with measured hourly surface air Rn-222 concentration and monthly Pb-210 deposition. The model verification was done with respect to the following points: 1) the sensitivity of vertical distribution of turbulent diffusivity and 2) the accuracy of spatial distribution of precipitation. In this report, improvement of the model performance is also discussed.