How large is the retrograde annual wobble?
Article first published online: 7 DEC 2012
Copyright 1991 by the American Geophysical Union.
Geophysical Research Letters
Volume 18, Issue 9, pages 1735–1738, September 1991
How to Cite
- Issue published online: 7 DEC 2012
- Article first published online: 7 DEC 2012
- Manuscript Accepted: 25 APR 1991
- Manuscript Received: 4 APR 1991
We compare recent measurements of polar motion (wobble) made by space-geodetic methods with older optical measurements. Multitaper spectra of these data show that the retrograde (clockwise) annual wobble is much larger in the older data than the newer data, implying systematic errors in the older techniques. Two additional analyses show evidence for a small retrograde motion in the newer data, which appears to be consistent between data types. This implies that the excitation of the retrograde wobble must be about half of the prograde excitation. None of the available estimates of the excitation shows full agreement with these observations.