Based on the regional acid deposition model(RADM),a high resolution model for species exchange in the troposphere(EM3)is designed.EM3 differs considerably in the following 5 aspects from RADM.First,the vertical grid l...Based on the regional acid deposition model(RADM),a high resolution model for species exchange in the troposphere(EM3)is designed.EM3 differs considerably in the following 5 aspects from RADM.First,the vertical grid levels in the planetary boundary layer(PBL)are increased.Second,layered vertical eddy diffusivity patterns in the troposphere(TL)are considered.Third,layered horizontal eddy diffusivity patterns within TL is used.Fourth,new dry deposition velocity pattern including the effect of plant canopy layer(CL)vertical structure is adopted.Fifth,advective scheme of second-order moment conservation with less numerical diffusion is used.OSCAR 4 case is comparatively simulated with both EM3 and RADM.The results show that 3-D distribution laws of chemical species in whole TL are forecasted by EM3 better than by RADM.Under the same conditions,all ratios of the central concentrations simulated with both models in lower PBL are more than 1.8,the maximum can be more than 3.展开更多
It is helpful to go deep into understanding the acid rainfall through studying the relation of two centers between acid deposition and rainfall and the relation of intensity between them.We adopt a three-dimensional E...It is helpful to go deep into understanding the acid rainfall through studying the relation of two centers between acid deposition and rainfall and the relation of intensity between them.We adopt a three-dimensional Eulerian regional acid deposition model,or NCAR-RADM,to calculate regional chemical concentrations and dry and wet depositions of acids.The temporally and spatially varied meteorological field is provided by a mesoscale meteorological model,vertion 4.We calculate dry and wet depositions of acids in eight kinds of different rainfall distributions.The results show that the wet depositions of acids near pollutant source is very sensitive to rainfall intensity in initial stage.The distribution of acid wet deposition will tend to that of rainfall intensity when rainfall intensity is small in source.And it will tend to that of initial pollutant concentration when rainfall intensity is large in source.展开更多
文摘Based on the regional acid deposition model(RADM),a high resolution model for species exchange in the troposphere(EM3)is designed.EM3 differs considerably in the following 5 aspects from RADM.First,the vertical grid levels in the planetary boundary layer(PBL)are increased.Second,layered vertical eddy diffusivity patterns in the troposphere(TL)are considered.Third,layered horizontal eddy diffusivity patterns within TL is used.Fourth,new dry deposition velocity pattern including the effect of plant canopy layer(CL)vertical structure is adopted.Fifth,advective scheme of second-order moment conservation with less numerical diffusion is used.OSCAR 4 case is comparatively simulated with both EM3 and RADM.The results show that 3-D distribution laws of chemical species in whole TL are forecasted by EM3 better than by RADM.Under the same conditions,all ratios of the central concentrations simulated with both models in lower PBL are more than 1.8,the maximum can be more than 3.
文摘It is helpful to go deep into understanding the acid rainfall through studying the relation of two centers between acid deposition and rainfall and the relation of intensity between them.We adopt a three-dimensional Eulerian regional acid deposition model,or NCAR-RADM,to calculate regional chemical concentrations and dry and wet depositions of acids.The temporally and spatially varied meteorological field is provided by a mesoscale meteorological model,vertion 4.We calculate dry and wet depositions of acids in eight kinds of different rainfall distributions.The results show that the wet depositions of acids near pollutant source is very sensitive to rainfall intensity in initial stage.The distribution of acid wet deposition will tend to that of rainfall intensity when rainfall intensity is small in source.And it will tend to that of initial pollutant concentration when rainfall intensity is large in source.
