我国大陆连续重力台站背景噪声的综合研究

本项目利用中国大陆构造环境监测网络30台gPhone重力仪和国内5台超导重力仪1s高采样的连续重力观测资料，进行我国大陆的地球背景噪声研究。与地震仪的观测数据获得的地球背景噪声相比，重力仪在较长周期的背景噪声研究方面有独特的优势。项目中采用了国际上近一二十年新发展的最小二乘谱分析方法，比传统的傅立叶谱分析更适用于实测数据。通过本项目的研究，可获得我国大陆的地球背景噪声水平，给出噪声的区域分布特征，深入研究地球面波（特别是长周期面波）的频谱特征，获得面波信号的频散曲线，计算其群速度和相速度，为进一步用重力高频噪声数据反演中国大陆的壳幔结构提供重力观测依据。

In the project, the background noise in the China mainland is investigated with 1s high samping rate and continous gravity observations recorded by 30 gPhone gravimeters in the Crustal Movement Observation Network of China and 5 superconduting gravimeters installed in the China. Comparing the Earth's background noise obtained by observed data from seismometers, the gravimeters have advantages in observing comparatively longer-period Earth's background noise. In the study, the Least-Squares Spectral Analysis (LSSA) developed internationally in the recent decades of years is used, which is more suitable to the real observations comparing with the classical Fourier Spectral Analysis. Through the studies in the project, the backgroud noise level in the our homeland is achieved, and its regional charateristic will be given. The frequency features for the surface waves (especially the long period surface waves) are deeply investigated. The dispersion curves of them are obtained and their group velocity and phase velocity are calculated. These reulsts provide gravity evidences to inverse the structure of the crust and mantle under the China mainland.