Astronomy and Astrophysics – Astronomy
Scientific paper
Sep 1993
adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=1993phdt.........1j&link_type=abstract
Ph.D. Thesis York Univ. (Ontario). Graduate Program in Physics and Astronomy.
Astronomy and Astrophysics
Astronomy
1
Dynamic Models, Earth Movements, Earth Rotation, Finite Element Method, Nutation, Very Long Base Interferometry, Earth (Planet), Earth Core, Variational Principles
Scientific paper
In view of the rapid improvement in the accuracy of rotational observations of the Earth, a more sophisticated theoretical model of rotational dynamics of the Earth is needed in order to infer new information about the Earth's deep interior from observations. Numerical calculations are presented of wobble and nutation modes of realistic Earth models. The finite element method is used for numerical implementation of a variational principle based on the subseismic approximation to the motion of the outer core. A new prograde free core nutation with a period of 538 solar days for the 1066A Earth model is obtained. It is also found that the period of the retrograde free core nutation is 450 solar days, about 10 days shorter than the period given by previous studies. For the first time, the displacement field of wobble-nutation modes is calculated and plotted out in detail. This allows a comparison with other theoretical modes. A very long base interferometry data set, covering a time interval of about nine years, is analyzed to search for the free core nutation modes predicted by the study. A retrograde free nutation with a period of about 431 days is found significant above the 95% confidence level. Incomplete correction for the retrograde annual term might account for the spectral peak identified as the free core nutation.
No associations
LandOfFree
Wobble-nutation modes of the Earth does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with Wobble-nutation modes of the Earth, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Wobble-nutation modes of the Earth will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-1565756