云南丽江台OSG-066重力潮汐观测结果及应用

基于云南丽江台超导重力仪OSG-066超过5 a的连续重力潮汐观测资料,获取高精度潮汐参数并构建地方重力潮汐模型,为丽江地区精确重力潮汐改正提供参考。研究9个全球海潮模型在丽江台的重力影响改正有效性,用时域内回归分析法和频域内小波分析法分别研究大气重力导纳值的变化特征,并利用观测潮汐数据估算自由核章动本征参数。结果表明,9个海潮模型在丽江台的重力影响改正效果基本一致,NAO.99b模型的改正精度较高;大气重力导纳值在时域和频域内均显示出较为明显的季节性变化特征,且与降雨量变化存在负相关关系。自由核章动本征周期为431.5(411.2,454.0)恒星日,品质因子为-2796。

Gravity Tide Observation with OSG-066 and Their Applications at Lijiang Station,Yunnan Province,China

Abstract: We use more than 5 years continuous data recorded with the observatory superconducting gravimeter(OSG-066) at Lijiang station, Yunnan province, China. High precision tidal parameters are obtained, and the local gravity tide model is established to provide a reference for accurate gravity tide deduction in Lijiang area. The correction effectiveness of gravity influence of ocean tide is computed with 9 new global tide models. In addition, the atmospheric gravity admittance is studied with regression analysis in time domain and wavelet analysis in frequency domain. The parameters of free core nutation are further estimated with the observed tidal parameters. The results show that gravity influence corrections of the 9 different ocean tide models are almost the same at Lijiang station, and correction accuracy of the tide model NAO.99b is slightly higher among them. Results of obtained atmospheric gravity admittance demonstrate that significant seasonal variation characteristics are found in both time domain and frequency domain; significant inverse correlation is found between precipitation data and atmospheric gravity admittance. The eigen period of free core nutation is 431.5(411.2, 454.0) sidereal days, while the quality factor is -2 796.