Oceanic signals in observed motions of the Earth’s pole of rotation

Author: Rui M. Ponte, J. Marshall and D. Stammer
Date: 
October 27, 1997
Type: 
Article
Venue: 
Nature
Citation: 

Ponte, R.M., D. Stammer, and J. Marshall, 1998. Oceanic signals in observed motions of the Earth’s pole of rotation. Nature, 319, 476-479.

Motion of the Earth's pole of rotation relative to its crust, commonly referred to as polar motion, can be excited by a variety of geophysical mechanisms1. In particular, changes in atmospheric wind and mass fields have been linked to polar motion over a wide range of timescales, but substantial discrepancies remain between the atmospheric and geodetic observations. Here we present results from a nearly global ocean model which indicate that oceanic circulation and mass-field variability play important roles in the excitation of seasonal to fortnightly polar motion. The joint oceanic and atmospheric excitation provides a better agreement with the observed polar motion than atmospheric excitation alone. Geodetic measurements may therefore be used to provide a global consistency check on the quality of simulated large-scale oceanic fields.