The long range transport of airborne material and its removal by deposition and washout—II. The effect of turbulent diffusion

摘要: Abstract The diffusion approximation is used to estimate long distance transport in the mixing layer with a view assessing accuracy of simple model Part I this paper and investigate buffering effect diminishing atmospheric turbulence as absorbing ground or sea approached from above. It confirmed that for SO 2 absence rain chemical reactions mean travel distances order 700 km can occur when vertical limited by an inversion at height about 1 km. Background concentrations travelling over such are reduced magnitude factor four. rainfall discussed I. shown effective deposition rate largely governed diffusive resistance low region adjacent surface fairly insensitive details roughness, etc. Overall velocities turn out be always cm s −1 less. Far source assumption constant net flux near valid confirming conventional methods deducing measurements concentration velocity profiles.