北京地区最新重力潮汐结果及其在检测液核共振效应中的应用  

The latest gravity tide results in Beijing and its application in detecting resonant effect of the fluid outer core

作　　者：孙和平 刘清超 吴书清[3] 陈晓东[1] 冯金杨 张苗苗[1,2] 徐建桥 李春剑[3] 

机构地区：[1]中国科学院测量与地球物理研究所大地测量与地球动力学国家重点实验室,武汉430077 [2]中国科学院大学,北京100049 [3]中国计量科学研究院,北京100029

出　　处：《地球物理学报》2017年第12期4699-4708,共10页Chinese Journal of Geophysics

基　　金：国家重点基础研究(973)计划项目(2014CB845092);国家自然科学基金(41621091;41674083;41374084;41574072)联合资助

摘　　要：利用中国计量科学研究院北京昌平基地iGrav-012超导重力仪最新观测资料,对其作仔细地预处理,根据调和分析方法精密测定了重力潮汐参数,基于负荷理论与卷积积分技术获得了包含HAM11a,DTU10,EOT11a在内的14个全球海潮模型的重力海潮负荷效应,利用近周日频段内潮波振幅因子的共振效应求解了自由核章动(FCN)的本征参数.调和分析结果表明,重力潮汐的观测精度非常高,标准差达到1.184nm·s-2.基于加汉宁窗的快速傅里叶变换方法获得地震频段的地震噪声等级(SNM)为0.206,说明该台站是低背景噪声的.周日主波O1和K1经海潮模型作负荷效应改正的平均有效性分别为83%和85%;使用13个高精度海潮模型进行迭积计算获得的FCN本征周期为430.0(427.8,432.3)恒星日,品质因子Q值为-5137.Using the latest observations recorded with superconducting gravimeter iGrav-012 at Changping lab of National Institute of Metrology, China, the gravimetric parameters are determined accurately based on harmonic analysis after carefully preprocessing of the raw data. Meanwhile, the loading effects of ocean tides on the gravity are calculated by means of loading theory and integral convolution technology with 14 global ocean tide models, which included HAM11a, DTU10 and EOT11a. Then, the intrinsic parameters of the free core nutation （FCN） are retrieved based on the resonance effect of the tidal amplitude factors in the diurnal band. The results show that the accuracy of tidal gravity observations is very high, with the standard deviation of 1.184 nm·s-2. Based on the FFT with Hanning window, the Seismic Noise Magnitude （SNM） in seismic band is obtained with the value of 0.206, which indicates that Changping lab is a low ambient noise station. With 14 ocean tide models, the mean loading correction effectiveness of wave O1 and K1 are 83% and 82%, respectively. On the basis of stacking method using 13 high-precision models, the FCN＇s eigenperiod is solved as 430.0 （427.8, 432.3） sidereal days, while the quality is a negative one as of -5137.

关 键 词：北京 重力潮汐参数 背景噪声 海潮负荷改正 自由核章动 

分 类 号：P228[天文地球—大地测量学与测量工程] P541[天文地球—测绘科学与技术]