Decadal modulation in length-of-day variations from solar activity: a wavelet approach

In this present paper, wavelet technique is applied to analyse the time series of the Earth’s length-of-day series during 1832—1997 and the sunspot relative numbers during 1700—2006, with emphasis on investigating external excitation source of the Earth’s variable rotation. The results show modulation action from solar activity plays an important role in decadal change of the Earth rotation, and this strengthens the conclusion that the Earth—s rotation is modulated by the solar activity.