8.3　Conclusion

According to DHR's forecast,the global ozone content will gradually increase in the next 20 years,the growth trend to keep the existing speed.About 2040 to reach the pre-1980 level.After the whole trend coefficient fluctuates around zero,the artificial factors decrease gradually.While periodic components play a major role in maintaining atmospheric ozone levels for about a decade of quasi-periodic fluctuations in the state.As shown in Figure 6.

Figure 6

According to the above analysis,this article also based on the average ozone content in the northern hemisphere into the established DHR model analysis,as shown in Figure 7.

Figure 7

The average annual ozone growth in the southern hemisphere is much faster than that in the northern hemisphere,and the fluctuation range is small.In the northern hemisphere,the ozone layer will probably return to its pre-1980 level by 2022—2030.Compared with the southern hemisphere,the ozone layer in the northern hemisphere recovery time there is a big uncertainty.The reason is that the change of total ozone in the southern hemisphere is mainly affected by the Montreal Protocol,while the northern hemisphere by the impact of human factors than the southern hemisphere,the northern hemisphere ozone rate of change in the forecast there is a large uncertainty.