Earth’s Rotation: Observations and Relation to Deep Interior

Jérémy Rekier, Benjamin F. Chao, Jianli Chen, Véronique Dehant, Séverine Rosat, Ping Zhu

Research output: Journal article publicationReview articleAcademic researchpeer-review

14 Citations (Scopus)


Abstract: Observation of the variations in the Earth’s rotation at time scales ranging from subdiurnal to multidecadal allows us to learn about its deep interior structure. We review all three types of motion of the Earth’s rotation axis: polar motion (PM), length of day variations (Δ LOD) and nutations, with particular attention to how the combination of geodetic, magnetic and gravity observations provides insight into the dynamics of the liquid core, including its interactions with the mantle. Models of the Earth’s PM are able to explain most of the observed signal with the exception of the so-called Markowitz wobble. In addition, whereas the quasi-six year oscillations (SYO) observed in both Δ LOD and PM can be explained as the result of Atmosphere, Oceans and Hydrosphere Forcing (AOH) for PM, this is not true for Δ LOD where the subtraction of the AOH only makes the signal more visible. This points to a missing—possibly common—interpretation related to deep interior dynamics, the latter being also the most likely explanation of other oscillations in Δ LOD on interannual timescales. Deep Earth’s structure and dynamics also have an impact on the nutations reflected in the values of the Basic Earth Parameters (BEP). We give a brief review of recent works aiming to independently evaluate the BEP and their implications for the study of deep interior dynamics.

Original languageEnglish
Pages (from-to)149-175
Number of pages27
JournalSurveys in Geophysics
Issue number1
Publication statusPublished - Feb 2022
Externally publishedYes


  • Earth’s rotation
  • Length of day
  • Nutation
  • Observations
  • Polar motion

ASJC Scopus subject areas

  • Geophysics
  • Geochemistry and Petrology


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