The theory of Smith (1977,1980) is generalized to include both forced and free rotations by introducing an arbitrarily rotating nutation frame.The Eulerien equations are transformed to include the following unknowns:t...The theory of Smith (1977,1980) is generalized to include both forced and free rotations by introducing an arbitrarily rotating nutation frame.The Eulerien equations are transformed to include the following unknowns:the angular velocity of the nutation frame with respect to the spatial frame,which represents the nutation,and the angles defining the orientation of the Earth with respect to the nutation frame,which represents the polar motion.Together with the definition of the nutation frame (as the definition of the nutation frame is arbitrary to some extent),one can solve simultaneously forced and free nutation and polar motion.As demonstrative examples,studies of nutation and polar motion are made by assuming the nutation axis to be the Earth’s figure axis,rotation axis and angular momentum axis respectively.And the case of the celestial ephemeris pole is also studied.展开更多
The present study aims to extend the traditional rotation theory of the rotational-symmetric Earth to the triaxial Earth. We reormulate the Liouville equations and their general solutions for the triaxial nonrigid Ear...The present study aims to extend the traditional rotation theory of the rotational-symmetric Earth to the triaxial Earth. We reormulate the Liouville equations and their general solutions for the triaxial nonrigid Earth and find that the traditional theory introduces some theoretical errors in modeling the excitation functions. Furthermore, we apply that theory to the atmospheric excitation and find that theoretical errors should not be neglected given the present measurement accuracy. Thus we conclude that the traditional theory of the rotation of the rotational-symmetric Earth should be revised and upgraded to include the effects of the Earth＇s triaxiality.展开更多
基金ProjectsupportedbytheNationalNaturalScienceFoundationofChi na (No .498740 0 3)
文摘The theory of Smith (1977,1980) is generalized to include both forced and free rotations by introducing an arbitrarily rotating nutation frame.The Eulerien equations are transformed to include the following unknowns:the angular velocity of the nutation frame with respect to the spatial frame,which represents the nutation,and the angles defining the orientation of the Earth with respect to the nutation frame,which represents the polar motion.Together with the definition of the nutation frame (as the definition of the nutation frame is arbitrary to some extent),one can solve simultaneously forced and free nutation and polar motion.As demonstrative examples,studies of nutation and polar motion are made by assuming the nutation axis to be the Earth’s figure axis,rotation axis and angular momentum axis respectively.And the case of the celestial ephemeris pole is also studied.
基金Supported by the National Natural Science Foundation of China (No.40974015)the Wuhan University Outstanding Doctoral Thesis Foster Fund (No.22)+1 种基金the Ph.D. Candidates Self-research (including 1+4) Program of Wuhan University in 2008 (No.49)the Open Fund of Key Laboratory of Geospace Environment and Geodesy, Ministry of Education, China (No. 08-02-02)
文摘The present study aims to extend the traditional rotation theory of the rotational-symmetric Earth to the triaxial Earth. We reormulate the Liouville equations and their general solutions for the triaxial nonrigid Earth and find that the traditional theory introduces some theoretical errors in modeling the excitation functions. Furthermore, we apply that theory to the atmospheric excitation and find that theoretical errors should not be neglected given the present measurement accuracy. Thus we conclude that the traditional theory of the rotation of the rotational-symmetric Earth should be revised and upgraded to include the effects of the Earth＇s triaxiality.
