8.2 DHR model decomposition TCO time series
According to the principle of DHR model,that is,each time data is obtained by adding different period components.Different parameters can be set by using KF/FIS filter to get different components.Therefore,DHR model can be used to analyze time series.The main components such as trend and period variation were extracted from the original data.
Through the original TCO time series data decomposition.
Figure 4
The Figure 4 shows the long-term trend of the original time series,the early stage shows a downward trend,but the rate of decline gradually slowed down.To the late showing a significant upward trend.
Conclusion：This component can be considered as a response to the implementation of the Montreal Protocol by the global ozone total,that is,the Montreal Protocol controls the total amount of ozone depleting substances in the atmosphere,leading to a global scale of ozone recovery.
Figure 5
The Figure 5 shows the extracted periodic components,showing quasiperiodic fluctuations of about 10 years,and the component in the 1980—2015 years,the comprehensive close to zero fluctuations,that is,for the global change in total ozone,the group only affects the periodic fluctuation of global ozone and has no substantial impact on the long-term change of total ozone.In view of this,the component can be considered by the solar cyclical activity and dynamic factors and other natural factors on the total ozone regulation.
The two components explained nearly 95%of the variance,so the remaining components can be considered as noise,and thus not be considered.