“…The emission inventory has been estimated by various studies (Katata et al, ; Saunier et al, ; Terada et al, ; Winiarek et al, ; Yumimoto et al, ), but it remains a major cause of the uncertainties in the simulated atmospheric 137 Cs concentrations because of the limited acquisition of direct measurements of radionuclide concentrations during their release. Internal elements refer to the components included in the numerical models, such as the physical processes of wet and dry deposition of 137 Cs (Morino et al, ; Quérel et al, ), clouds and rain (Saito et al, ), grid resolution (Sekiyama et al, ), and horizontal diffusion (Terada et al, ). Overall, the results derived from numerical models have large discrepancies.…”