Models for polar motion
Luni-solar tidal forcing
Ocean loading
Atmospheric loading
Continental water loading or unknown cause
POLAR MOTION

Diurnal and subdiurnal*


Solid Earth quasi-elastic response

Brzezinski et al. 2002
tidal

  • IERS 1996

  • IERS 2010


  • non tidal

    Brezinski et al. 2004

    thermal + tidal

    Brzezinski et al. 2002
     
    POLAR MOTION

    > 2 days

    Solid Earth quasi-elastic response
    Brzezinski et al. 2002 tidal

    PM and its excitation: Dickman, Weiss, and empirical models, Tab 1 of Gross (2008)
    POLAR MOTION

    Decadal and secular


    Solid Earth Visco-elastic response
     

     
    * Only prograde diurnal terms of the polar motion are considered, retrograde diurnal components are actually estimated as nutation offsets. Semidiurnal, terdiurnal and other subdiurnal terms are composed of both prograde and retrograde parts.

    Polar motion effects
      Solid Earth quasi-elastic contribution (solid Earth pole tide) From 2 days to ~ 20 years

    Hydrostatic ocean contribution (ocean pole tide)

    From 10 days

    Secular / multi-decadal polar motion (post-glacial rebound,...)

    From ~ 20 years
    On degree 2 geopotential (or off-diagonal inertia moment) IERS 2010 - Chapter 6.4: Eq. 6.22 IERS 2010 - Chapter 6.5 (Eq. 6.23a/b and 6.24) from Desai model (2002) Eq. 24

    IERS 2010 polynomial trend Chapter 6.2 (Eq. 6.5) and Chapter 7 (Eq. 7.25)
    On solid Earth deformation Solid Earth pole tide IERS 2010 Update: Chapter 7.1.4: Eq. 7.23 + 7.22/7.24) Ocean pole tide loading for periods < 20 years: --> IERS 2010 Update: Chapter 7.1.5 Mean pole