Observation of superconducting gravimeter at Jiufeng seismic station
Observation of superconducting gravimeter at Jiufeng seismic station
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九峰地震台超导重力仪观测
DOI：
10.6038/j.issn.0001-5733.2012.06.010
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发表时间：
2012
期刊：
影响因子：
--
通讯作者：
Hao Hong-Tao
中科院分区：
文献类型：
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作者：
Li Hui;Liu Zi-Wei;Kang Kai-Xuan;Hao Hong-Tao
利用连续相对重力和连续GPS观测可以研究地表下的质量传递和垂直形变之间的关系。与流动相对重力和绝对重力相比，连续相对重力可以监测重力变化和质量传递的全过程，避免了测量精度和时间分辨率低的缺点。本文分析了九峰地震台超导重力(SGC053)记录的13000多小时重力资料，以及同址绝对重力数据、大气压力、周围GPS站、WHN IGS站点和WHJF站点的垂直位移、GRACE月时变重力和两个全球大陆水存储模型(GLDAS，GLDAS，GLDAS利用调和分析方法、大气压力导纳模型、极点潮汐模型以及与GRACE结果和/或蓄水模型的相关分析，对固体固体潮、大气压力、极点潮汐和大陆水负荷引起的重力变化进行了校正，并利用共点绝对重力测量对仪器漂移进行了校正。在此基础上，解决了剩余重力时间序列与GPS垂直形变之间的关系。对SGC053重力记录进行了跨度约一年半的调和分析，与海洋潮汐负荷(3×10-8m·S-2)相比，气压重力(12×10-8m·‰-2)和极潮重力(10×10-8m·S-2)要大得多。结果表明，夏季和秋季由大陆水负荷引起的剩余重力约为(6~8)×10-8m·S-2，与GLDAS结果和全球大陆水负荷(GLDAS，CPC)的剩余重力变化相比较。经水负荷校正的重力变化与距SGC053约15公里的GPS站的垂直形变呈完全负相关，长期垂直形变为下沉，重力变化率约为1.79×10-8(m·S-2)/A。重力与高程变化与局部地壳垂直运动的比值约为-354×10-8(m·S-2)/m。
The relationship between the mass transfer beneath the earth surface and the vertical deformation could be studied using continuous relative gravimetry and continuous GPS observation.Compared to mobile relative gravimetry and absolute gravimetry,continuous relative gravimetry could be used to monitor the whole process of gravity changes and mass transfer,avoiding low measurement precision and temporal resolution.In this paper,more than 13000 hours gravity data recorded at Jiufeng seismic station using superconducting gravimetry(SGC053) are analyzed along with co-located absolute gravimetry data,air pressure,vertical displacement of surrounding GPS stations,WUHN IGS site and WHJF site,GRACE monthly time-variable gravity and two global continental water storage models(GLDAS,CPC).Gravity variations induced by solid earth tide,air pressure,pole tide and continental water loading are corrected using harmonic analysis method,atmospheric pressure admittance model,pole tide model and the correlation analysis with GRACE results and/or water storage models,then instrument drift is also corrected using co-located absolute gravity measurements.Based on the above processing,the relationship between the residual gravity time series and GPS vertical deformation is addressed.The harmonic analysis result for SGC053 gravity records,spanning about one and half years,shows that the white noise is about 1.14~1.40×10-8m·s-2 and the tidal factor errors of dominant tidal groups reach about 0.1‰.Compared to ocean tide loading(3×10-8m·s-2),the gravity due to air pressure(12×10-8m·s-2) and pole tide(10×10-8m·s-2) is much larger.The drift of SGC053,about 2.18×10-8(m·s-2)/a,is estimated using 4 absolute gravity co-located records of FG5-232.The result shows that the residual gravity caused by continental water loading in summer and autumn is about(6~8)×10-8m·s-2,by comparing residual gravity variations with both GARCE result and global continental water loading(GLDAS,CPC).Gravity variations corrected for water loading show perfect negative correlation with the vertical deformation of the GPS station,about 15km away from SGC053,so as to data in spring and winter.And the long-term vertical crustal deformation is subsidence and the gravity change rate is about 1.79×10-8(m·s-2)/a.The ratio of the changes in gravity and altitude related to the local vertical crustal movement is about-354×10-8(m·s-2)/m.