Wavelet analysis provides a new tool for studying Earth's rotation

Abstract
The solid Earth's rotation varies slightly with time due to geophysical processes that involve motions and redistributions of mass occurring on or within the Earth, as dictated by the conservation of angular momentum. In particular, these variations Δ LOD) in the atmosphere in terms of the axial atmospheric anglar momentum (AAM) are the primary cause for nontidal length‐of‐day variations on timescales of several days to several years [e.g., Rosen, 1993]. Here Δ LOD is a convenient measure of Earth's rotational speed relative to the uniform time kept by atomic clocks.