Phasor diagram of annual and semi-annual variations of the mass term of polar motion excitation computed from GRACE solutions, from ‘geodetic’ excitation and from geophysical fluids models. The circle radiuses represent the standard error of the least-square estimate. G-WC1, geodetic mass term estimated using the wind term from NCEP/NCAR reanalysis and the current term from SBO series; G-WC2, geodetic mass term estimated using the wind term from NCEP/NCAR reanalysis and the current term from ECCO-GODAE series; CSR, GFZ, JPL, GRGS, ‘gravimetric’ excitations; PAOH1, atmospheric (NCEP/NCAR) + oceanic (SBO) + hydrologic (CPC) pressure term; PAOH2, atmospheric (NCEP/NCAR) + oceanic (ECCO-GODAE) + hydrological (CPC) pressure term.