宜昌台超导重力观测中的海潮与大气负荷效应研究

Ocean Tide and Atmospheric Loading Effects of Superconducting Gravimetric Observations at Yichang Station

基于2017年宜昌地震台超导重力仪观测数据,对数据预处理、极移改正和长周期趋势改正后的重力潮汐观测数据进行调和分析,获得宜昌台精确地方重力潮汐参数,选取NAO.99b和osu.Chinasea.2010海潮模型研究海潮负荷对重力观测的影响。结果表明,宜昌台海潮负荷变幅约为25 nm·s^(-2),经海潮改正后潮汐因子有所改善。采用时域导纳方法以及基于全球大气模型ERA-Interim计算宜昌台大气重力负荷效应,研究结果表明,宜昌台大气重力导纳值为-3.2193 nm·s^(-2)·hPa^(-1),近区大气重力负荷变幅约为160 nm·s^(-2),远区大气重力负荷变幅可达70 nm·s^(-2),在进行超导重力数据处理分析时全球大气负荷效应不能忽略。

Based on the superconducting gravimetric observations at Yichang seismic station in 2017,we obtain the accurate local gravity tidal parameters of Yichang station by harmonic analysis of observation data after data preprocessing,polar motion correction and long-period trend correction.We select the NAO.99b and osu.Chinasea.2010 ocean tide models to study the influence of ocean tide loading on gravimetric observation.The results show that the amplitude change of ocean tide loading at Yichang station is about 25 nm·s^(-2),and the tidal parameters improve after ocean tide loading correction.We use the time-domain admittance method and global atmospheric model ERA-Interim to calculate the atmospheric loading effect of Yichang station.The results show that the atmospheric gravity admittance factor of Yichang station is-3.2193 nm·s^(-2)·hPa^(-1).The amplitude change of atmospheric gravity loading in the near region is about 160 nm·s^(-2),and can reach 70 nm·s^(-2) in the far region.The global atmospheric loading effect cannot be ignored when processing and analyzing superconducting gravimetric data.