Diminished Chandler Wobble after 2015 : link to mass anomalies in 2011

Abstract

Observed polar motion after 2015 is dominated by the annual wobble, due to unprecedented amplitude reduction of the Chandler Wobble component. This change is likely due to suppression of the 433-day-period free wobble by geophysical excitation sources. Our experiments show that excitation changes in the period 2011–2012 are the most significant contributors to the diminished Chandler Wobble after 2015. Numerical models and satellite observations suggest that the Chandler Wobble suppression was largely driven by the 2011–2012 changes in continental-scale air and terrestrial water mass redistribution.