武汉和京都台站超导重力仪高精度潮汐重力观测结果

利用高精度潮汐重力场观测研究地球物理学和地球动力学问题已成为当今地学工作者的共识.由于某些信号十分微弱且具有区域和全球分布特征,相当一部分信号被混合在常规仪器的观测噪声水平上,因此获得全球分布的第一手高精度观测资料显得尤为重要.超导重力仪具有精度高,连续性和稳定性好等特征,期望能在测定区域和全球重力场的精细结构方面发挥重要作用.有18个台站参加的全球地球动力学合作项目于1997年7月份开始实施,其主要目的是解决诸如固体潮、地核近周日晃动、核模、地球自转和极移,地球和大气海洋的耦合机理以及由构造运动引起的重力场变化等热点问题.我们曾研究过中比法三国的超导重力仪潮汐观测资料,获得了欧洲和亚洲不同地区潮汐常数及分布特征.本文将利用武汉和日本京都三台超导重力仪观测资料研究亚洲地区大陆和海岛上的潮汐波振幅因子和相位滞后的时间变化特征以及各参数的误差估计等,同时将检测由大气和海潮变化产生的重力信号.文章分数据处理方法、潮汐参数测定、大气重力信号、海潮重力信号、潮汐参数的时间变化、非潮汐重力场变化特征等几方面叙述.

Observation Results of the High Precision Tidal Gravity with Superconducting Gravimeters at Stations Wuhan and Kyoto

The long series tidal gravity observations recorded with superconducting gravimeters (SGs) SCG#4,SCG#8 and SCG#9 at stations Wuhan/China and Kyoto/Japan are comprehensively studied.The tidal amplitude factors and phase differences are determined accurately using Eterna method.The results show that the accuracy of the main wave tidal amplitudes and that of the phase differences is given as at 0.01 μgal and at 0.01° level.The temporal variation of the tidal amplitude factors,phase differences,long term trend and high passed signals are discussed in details.The coefficients between the tidal gravity and pressure used to correct pressure influence are determined.The oceanic gravity signals are corrected based on CSR3.0 global cotidal maps,comparing with theoretical tidal models, after apply for the loading correction,the average discrepancy for 8 main waves are reduced from 1.52% to 0.41%(Wuhan) and from 3.77% to 0.66%(Kyoto).