1. Fig. 1 Observed pole position data.
Observed pole position data. Mean monthly polar motion excitations (black lines) derived from the observed daily values after removing semiannual, annual, and Chandler wobbles. Smoothed solutions (blue lines) reveal quasi-decadal variability in the corresponding component of the 20th-century linear trend (dashed red lines). Cyan shadows in the background cover our study period, over which the drift direction deviates (solid red lines) from the long-term linear trend.
Surendra Adhikari, and Erik R. Ivins Sci Adv 2016;2:e
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