A Nepali scientist led research at NASA has made a groundbreaking discovery about why Earth’s polar motion was moving eastwards dramatically – from Canada to the United Kingdom – since the beginning of the new Millennium, and the mystery behind the east-west swings in the polar motion on a decadal basis.
According to Surendra Adhikari and Erik Ivins’ research, both melting of polar ice sheets and global land water storage pattern are responsible for the change in Earth’s rotation. Their findings were published in a paper “Climate-driven polar motion: 2003–2015” in journal Science Advances on April 8, 2016.
“For the first time ever, we have presented a plausible physical mechanism that explains the enigmatic decadal oscillation of the pole. It is ‘decadal-scale variability in (global) land water storage pattern’ that drives the ‘decadal polar motion’,” Adhikari said.
The NASA scientists analysed space deodectic and satellite gravimetric data from 2003 to 2015 to show that all of the main features of polar motion are explained by global-scale continent-ocean mass transport, owing to the combined effect of melting of the Greenland and West Antarctic ice sheets and the changes in global continental water storage.
Earth’s spin axis wobbles on a decadal pattern – meaning in some years it heads to the east and in the following years to the west, and this decadal swing continues. This has been well-documented for 115 years.