The result shows that there are main periods in the amplitude variation, such as about 6.5-year and 40-year, and the periods have the character of variation with time.

结果表明，极移振幅变化中存在着约6.5年和约40年的主要周期，且它们均具有一定程度的时变性。

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The result shows that there are main periods in the amplitude variation, such as about 6.5-year and 40-year, and the periods have the character of variation with time.

结果表明，极移振幅变化中存在着约6.5年和约40年的主要周期，且它们均具有一定程度的时变性。

youdao