Synoptic Analysis of Tropospheric Ozone Variations Case Study: Tehran Metropolitan

Although the amount of tropospheric ozone in the troposphere is natural, but abnatural amounts of this molecule formed during the photochemical processes in the atmosphere, it has become one of the most important urban air pollutants. In this study relied on environmental approach to Circulating, to identify status of the tropospheric ozone in the period 2001-2011. Troposphere ozone values and the values of climatic were received through the environmental pollution monitoring center of Tehran Province - depending on the Environmental Organization-and Tehran Air Quality Control Company-depending on the Municipal. High atmospheric data prepared through the database NCEP/NCAR. Followed by circulation patterns that create the maximum amount of ozone, with the help of cluster analysis were extracted and classified. The results show that the highest concentration and intensity of this pollutant Occurs during the warm months of July and August, which the main its circulation patterns are surface low-pressure and Subtropical High Pressure. Although in other seasons of the year are observed ozone maxima. In general what causes the tropospheric ozone concentration in the Tehran Metropolis is surface stability. Because, stability increases photochemical processes in the atmosphere, consequently, increases the concentration of tropospheric ozone. Causes of this stability are patterns of upper dynamic high-pressure such as Subtropical High Pressure in summer and patterns of thermal high-pressure on the surface such as the Siberian high-Pressure in winter.