Models for polar motion  
Lunisolar tidal forcing

Ocean loading

Atmospheric loading 
Continental water loading or unknown cause


POLAR MOTION Diurnal and subdiurnal* Solid Earth quasielastic response 
Brzezinski et al. 2002 
tidal non tidal Brezinski et al. 2004 
thermal + tidal Brzezinski et al. 2002 

POLAR MOTION > 2 days Solid Earth quasielastic 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 Viscoelastic 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 quasielastic contribution (solid Earth pole tide)
From 2 days to ~ 20 years 
Hydrostatic ocean contribution (ocean pole tide) From 10 days 
Secular / multidecadal polar motion (postglacial rebound,...) From ~ 20 years 

On degree 2 geopotential (or offdiagonal 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 