Fig. 12From: Recovery of the 6-year signal in length of day and its long-term decreasing trendVariations of the Earth’s oblateness and its secular variation showing quadratic trend \( {\ddot{J}}_2 \)≈18 × 10−13/year2 (a) (see Cheng et al. 2013) and (b) the relationship between ∆LOD predicted by ΔJ 2 and the secular variation of the 6-year signalBack to article page