对月日潮汐摩擦耗散的估计

月日潮汐摩擦和地球惯量矩变化是日长长期变化的主要原因．在本文中，利用最新的地球物理和古生物钟数据，对过去15亿年以来的月日潮汐摩擦、地球惯量矩变化和日长长期变化等作了数值对比研究．由此得到二个重要结论：一是仅利用地球的自转形变不能解释J2的变化，这说明地球的重力分异现象至今仍存在着；其二是在几亿年前的潮汐摩擦比现在大得多，若取潮汐耗散与距离的立方成反比时，理论结果与由古生物钟得到的回归年日数和朔望月日数数据较为符合。

Estimation of Luni-solar Tidel Dissipation

Luni-solar tidel dissipation and the Earth's momentum variation are two main reasons for the long-period variation of length-of-day. By using new geophysical data and the paleontological clocks data, It is estimated and compared luni-solar tidel dissipation, the Earth's momentum variation, the long-period variation of length-of-day and the length of synodic month in the passed 1500 Ma. Accoding to the results, two important conclution are obtained. Firstly, the J2 variation can not explained only by thr Earth's rotational deformation, which means that the dense materials sank toward the Earth center and the low-density materials rise toward the Earth,s surface are still going on. Secondly, in the paleogeology period, there were more larger lunar tidel dissipation, under a assumption that lunar tidel dissipation is inversely propotional to the cube of the distance from Earth to moon, the theoritical numbers of days in an year and in a synodic month may coinsident very well with that obtained from the paleontological clocks data.