NUMERICAL MODELS OF TRANSPORT, DIFFUSION AND FALLOUT OF STRATOSPHERIC RADIOACTIVE MATERIAL

摘要

A numerical model in two dimensions capable of simulating diffusion, mean circulation transport, particle-fall velocity -and tropospherlc ralaout is described. The model incorporates a general anisotropic diffusion process with the principal axis of diffusion oriented along lines of constant potential vorticity which are approximated to be parallel to the tropopause con figuration. Rainout is simulated by the fractional removal of material at selected rain "formation" levels;the fraction removed at any latitude is proportional to the observed rainfall (climatological) at that latitude. The capability of the model has been extended by incorporating a four season variation of the meteorological parameters.