Rapid variations in polar motion during the 2005–2006 winter season

Abstract

The terrestrial motion of the Earth's rotation pole shows mainly two large oscillations: the Chandler and the annual wobbles driven by mass redistributions in surface geophysical fluids. These contributions interfere destructively every 6.4 years, slowing down the pole at that period of time. This is the case for the recent period from November 2005 till February 2006. Due to the high precision of Earth orientation data of these days and for the first time in the history of polar motion observation, very small structures of the motion are observed. We compared the observed polar motion with the contribution of atmosphere and oceans predicted from global atmospheric and oceanic analyses and models. We clearly see that centimeter level polar motion displacements during the 2005–2006 winter season are almost fully explained by major pressure events on the continents and on the ocean, especially a depression over Northern Europe in‐phase with similar events over North America.