Аннотация:With the improvement to the theory of P. Melchior concerning tide and nutation, we obtain the precession and nutation moment induced by high order tidal generating potential, and an associated dynamical equation of polar motion and nutation for the rigid Earth. Then CIP of Earth is theoretically and rigorously defined. Under the effect of every order tidal moment, the expression of precession and nutation for CIP axis is presented. Theoretical deduction shows that precession and nutation moment induced by odd order's tidal generating potential cause out-of-phase of longitude and obliquity nutation, that is, the cosine term in longitude nutation and the sine term in obliquity nutation. Finally, from expansion of precise tidal generating potential of Xi Qinwen, a new rigid Earth nutation sequence is established, which consists of 737 terms in all. The new nutation sequence is a better complement to the nutation sequence REN2000 of the rigid Earth adopted by IERS2003, which contains 678 solar-lunar nutation terms.
