The Numerical Simulating Of Spatial And Temporal Distribution Of Ozone Formation In Complex Terrain By CB-IV Mechanism

The spatial and temporal distribution of ozone is simulated in the complex terrain by CB-â…£ mechanism numerically in order to understand formation of ozone, feature of variation, trend in photochemical reaction in studied area (52km×37km) during the typical ozone episodes. The law of ozone formation from all sorts of precursors and source categories under typical meteorological conditions is explored. This would provide basis of scientific strategy to control and abate pollution and protect ecological environment.Hydrostatic mesoscale model is used to simulate the meteorological field with the high resolution of 500m×500m, in which governing equations are written in a terrain-following coordinate and advection-diffusion equations are numerically split, simultaneously.Emission inventory is established by emission factor, in which the anthropogenic and biogenic VOCs, NOx, CO emission sources is evaluated, A new method is developed to estimate biogenic VOCs emissions with actual monitoring data of Photomorphgenetically Active Radiation(PAR). In term of the character of source categories, the time allocation and the chemical split is made furthermore in order to meet the demand of modeling with high spatial and temporal resolution. The contribution and feature of different source categories of is disclosed too.Based on the emission inventory and meteorological field with high spatial and temporal resolution, the ordinary differential equation(ODE) group of photochemical reaction rates are established according to CB-â…£ mechanism while the ODE is solved by means of GEAR method. K theory is applied to simulate the ozone episode of Aug 14,1999. The level of O₃, OH, HCHO, PAN, NO₂, NO concentration is calculated, and the values of simulation are evaluated by comparing with actual value at the same time and same site synchronously, The result shows that the simulation data is consistent well with the on-site actual value on time serials and concentration levels. The grid of Qingniwaqiao site is taken as an example, the scenario of ozone formation in this grid is simulated and the isopleths plot of Empirical Kinetic Modeling Approach(EKMA) is drawn, the ratio of VOCs to NOx has a value of 6:1. It is an effective and scientific measure for designing emission control strategies.