Table 2: Correlations between the polar motion interannual variations estimated from geodetic residuals, GRACE solutions, and CPC and GLDAS hydrological models. Correlation values are better for than . This discrepancy is possibly caused by errors of the oceanic model removed from the geodetic observations.a

Percentage of explained varianceCorrelation
Magnitude Phase degree

G-A-O/GRACE −7 40 0.3 0.7 0.6 −34
G-A-O/CPC 9 37 0.3 0.6 0.6 −25
G-A-O/GLDAS 11 45 0.3 0.7 0.6 −22
GRACE/CPC −22 34 0.2 0.6 0.6 27
GRACE/GLDAS 37 4 0.6 0.4 0.5 23

aAccording to the Student-t test, the significance level of correlation is 0.17. The standard error of the difference between two values of correlation is 0.19. G-A-O: geodetic residuals (geodetic-atmospheric-oceanic excitations), GRACE: GRACE solutions of GRGS, CPC, and GLDAS: hydrological excitations.