Detection of free core nutation resonance variation in Earth tide from global superconducting gravimeter observations

被引：16

作者：

Cui, Xiaoming ^{[1
]}

Sun, Heping ^{[1
,2
]}

Xu, Jianqiao ^{[1
]}

Zhou, Jiangcun ^{[1
]}

Chen, Xiaodong ^{[1
]}

机构：

[1] Chinese Acad Sci, Inst Geodesy & Geophys, State Key Lab Geodesy & Earths Dynam, Wuhan 430077, Hubei, Peoples R China

[2] Univ Chinese Acad Sci, Beijing 100049, Peoples R China

来源：

EARTH PLANETS AND SPACE | 2018年 / 70卷

基金：

中国国家自然科学基金;

关键词：

Free core nutation; Superconducting gravimeter; Earth tide; Temporal variation; PARAMETERS; PERIOD; EXCITATIONS; STABILITY; MODELS;

D O I：

10.1186/s40623-018-0971-9

中图分类号：

P [天文学、地球科学];

学科分类号：

07 ;

摘要：

In order to verify the time variability of free core nutation (FCN) period, global superconducting gravimeter (SG) observations were analyzed based on synthetic test data. The gravity data series were synthesized to check the detectability of resonance variation caused by FCN period change. The tests indicate that the discrepancy between the FCN periods determined by SG and VLBI observations is caused by the high correlation between the FCN parameter and the amplitude factor of the.1 wave. The K1 wave is more sensitive to the FCN period change than other diurnal waves. The limit of the standard deviation of the K1 wave is found for more precisely observing the FCN period change. Tidal parameters of diurnal waves estimated from long series of 20 global SG stations were analyzed. A common variation trend is found in the amplitude factor of both K1 and.1 waves in all 8 stations above the limit, which indicates the FCN period may be not so stable in time. Furthermore, the variation in the K1 and.1 waves constrains the FCN period change to between 2.5 and 4 sidereal days, which also agrees with the possible variation from the current VLBI and SG observations.

引用

页数：12