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3. Ozone contribution from the stratosphere

Figure 1 shows the percent contribution of stratospheric ozone to the tropospheric ozone distribution at the surface and 500 hPa for January and July.

Surface contribution is greater than 50% in the mid-high latitude in winter time and generally smaller than 10% in the polluted region in summer time, reflecting strong photochemical production of ozone. At 500 hPa altitude, contribution in the tropical region is small throughout a year because of intensive and deep convection, short life time of ozone associated with high humidity, and ozone chemical production due to lightning NO_x and biomass burning emission.
Figure 2 shows zonal averaged ozone contribution from the stratosphere. The similar seasonal variation as Figure 1 is seen.

Figure 3 indicates the effect of stratospheric ozone on seasonality of surface ozone concentration. Ozone from the stratosphere does not seem to control seasonality of surface ozone in these selected sites.

Tropospheric ozone budget in the model is seen in Table 1. Stratospheric ozone influx is relatively small compared to chemical production in the troposphere. The value of 636 TgO3/yr is within a range suggested in recent literatures(typically 400-1000 TgO3/yr).