Global tropospheric ozone dynamics - Part I: Tropospheric ozone precursors- Part II: Numerical modelling of tropospheric ozone variability

(Part I). An overview of the tropospheric ozone changes is presented focuss ing mainly on the tropospheric ozone precursors. The complexity of the prob lem is shown through the consideration of a great number of relevant substa nces, like nitrogen compounds, volatile organic compounds, peroxyacetyl nit rate, hydroxyl radical, carbon monoxide, alkyl nitrates. The up-to-date kno wledge on the relevant numerical modelling is presented in Part II. (Part II). Various causes of tropospheric changes have been considered in P art I in connection with the analysis of observation data. It is clear howe ver, that the principal instrument for understanding numerous and often int eracting causes of ozone changes is numerical modelling. A review of the cu rrent status of the numerical modelling has been made for the variability o f the ozone concentration in the troposphere. Observation data on troposphe ric ozone and relevant numerical modelling results show that a necessity ex ists to get more adequate global observational data.