Variation of the equatorial moments of inertia associated with a 6-year westward rotary motion in the Earth

The westward-propagating rotary wave-2 displacement field in the mantle with the period of 6 years (Ding and Chao, 2018) predicts an ensuing 6-year variation in the Earth's two equatorial principle moments of inertia. In this paper we search for such signals in the sectoral Stokes coefficients C22 and S22 of the Earth's gravitational field. We analyze the monthly ΔC22 and ΔS22 data series derived from the satellite laser-ranging measurements for...