Hydrological Excitation of Polar Motion Derived from GRACE Gravity Field Solutions

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 𝜒₂ than 𝜒₁. This discrepancy is possibly caused by errors of the oceanic model removed from the geodetic observations.^a

	Percentage of explained variance		Correlation
					𝜒1+𝑖𝜒2
	𝜒1	𝜒2	𝜒1	𝜒2	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 90% 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.