日长的十年尺度变化研究  

A STUDY OF THE DECADAL FLUCTUATIONS IN LENGTH OF DAY

作　　者：吴斌[1] 彭碧波[1] 钟敏[1] 

机构地区：[1]中国科学院测量与地球物理研究所动力大地测量开放实验室,武汉430077

出　　处：《天文学报》1999年第4期360-363,共4页Acta Astronomica Sinica

基　　金：国家自然科学基金;国家攀登计划"现代地壳运动和地球动力学研究"资助

摘　　要：用高精度的日长资料和由人卫激光测距（ＳＬＲ） 解算出的地球引力场系数Ｊ２ 的变化序列ΔＪ２ ，证明地球各圈层的物质迁移对日长１０ 年尺度变化贡献仅占日长１０ 年尺度变化的４ ％ ，可以忽略；认为１０ 年尺度变化主要来源于地球各圈层的内力矩或相对角动量部分。Two very precise data sets, i.e. the variation of length of day (LOD) determined by space techniques and the geopotential coefficient ( Δ J 2) derived from satellite laser ranging (SLR), are used to study the decadal fluctuations in LOD. Instead of considering complex geophysical mechanisms, the authors use the observed Δ J 2 to calculate the contribution of mass redistribution of the Earth and find that this contribution amounts to 4% of amplitude of LOD at decadal time scale and hence is not large enough to excite the fluctuations. The results also demonstrate that the decadal fluctuations in LOD mainly come from the excitations of internal torques or relative angular momentum in the Earth.

关 键 词：日长 地球引力场 人卫激光测距 尺度变化 自转 

分 类 号：P183.31[天文地球—天文学]