Rigid-Earth Nutation Models
Abstract
Despite the fact that the main causes of the differences between the observed Earth nutation and that derived from analytical calculations come from geophysical effects associated with nonrigidity (core flattening, core-mantle interactions, oceans, etc.), efforts have been made recently to compute the nutation of the Earth when it is considered to be a rigid body, giving birth to several "rigid Earth nutation models." The reason for these efforts is that any coefficient of nutation for a realistic Earth (including effects due to nonrigidity) is calculated starting from a coefficient for a rigid-Earth model, using a frequency-dependent transfer function. Therefore, it is important to achieve high quality in the determination of rigid-Earth nutation coefficients to isolate the nonrigid effects that are still not well-modeled. After reviewing various rigid-Earth nutation models that have been established recently, and their relative improvement with respect to older ones, the authors discuss their specifics and their degree of agreement. Sections discuss the following: evolution of the rigid-Earth nutation theory in the 1990s, new developments in rigid-Earth nutation theory, the effects on nutation of the non-zonal harmonics of the third and fourth degree, the sub-microarcsecond rigid-Earth nutation series REN 2000, and the diurnal and sub-diurnal nutations of REN 2000.
Document Details
- Document Type
- Technical Report
- Publication Date
- Mar 01, 2000
- Accession Number
- ADA435818
Entities
People
- J. Souchay
Organizations
- Paris Observatory, PSL University