Abstract: To meet the stringent requirements for precise prediction of radioactive pollutant dispersion in nuclear facility regions, this study investigates the optimization of simulation parameterization schemes for multi-scale atmospheric flow fields. A numerical model was developed based on three-dimensional non-hydrostatic fully compressible equations to systematically evaluate the applicability of 192 parametric combinations across three typical terrains (inland flat, coastal flat, and coastal complex terrains). High-precision topographic data and land use characteristics from representative domestic nuclear facility sites were selected, with the European Centre for Medium-Range Weather Forecasts (ECMWF) ERA5 reanalysis data serving as the initial field. Multi-scale nested simulations were performed using the RAMS regional atmospheric model. The validity of the simulation results for various parametric schemes was verified using metrics such as the root mean square error (RMSE) of wind speed and the mean absolute error (MAE) of wind direction. The findings indicate that for shortwave radiation schemes, the Mahrer/Pielke scheme is recommended in coastal mid-to-low latitude areas, while the Chen scheme is more suitable for inland flat regions. Among planetary boundary layer schemes, the Cyclic scheme effectively mitigates lateral boundary effects.

Key words: radioactive airborne effluent, multi-scale flow field simulation, numerical simulation, parameterization scheme