长期极移与冰期后地壳反弹理论

SECULAR DRIFT OF THE EARTH' S POLE AND THE POST-GLACIAL REBOUND

基于冰期后地壳反弹理论，采用地球上4个最大冰帽的参数，计算了最近21000年以来冰帽的融化对地球惯性张量的影响，得到理论的长期极移方向为西经74°2。现代空间测地技术的观测结果表明，北美板块不存在明显的北向运动，所以国际上9个纬度观测序列的平纬近80年的长期变化存在着随经度的系统性分布尚不能得到很好解释。因此，现代纬度变化研究结出3－4mas／a的长期极移结果有待进一步证实。

The perturbations of moment of inertia tensor of Earth caused by the ice melting within the recent21000 years are calculated by using the paramters of four biggest ice sheets including the Laurentia,Fennoscandia. Greenland and Antaretica basing on the recent model of Post - glacial rebound ICE - 4G,and the theoretical direction of secular drift rate of the Earth's pole with 74°. 2 is obtained. It is shown that the visible difference of the secular drift rates of mean latitude between stations of eastern and western hendsphere can not be well explained by removing the station's motions basing on the ITRF94 and NNR-NUVEL-1A model. Therefore, the results of secular drift rate of the Earth's pole with 3～4 mas/a derived from modern analysis would be fruther studied. The theoretical derivation of secular drift rate of the Earth's pole will be studied basing on the ICE - 4G model and the estimation of mean lower mantle viscosity.