Stacking gravity tide measurements and nutation observations in order to determine the complex eigenfrequency of the nearly diurnal free wobble
Stacking gravity tide measurements and nutation observations in order to determine the complex eigenfrequency of the nearly diurnal free wobble
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DOI：
10.1029/94jb00133
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发表时间：
1994-05
影响因子：
--
通讯作者：
P. Defraigne;V. Dehant;J. Hinderer
中科院分区：
文献类型：
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作者：
P. Defraigne;V. Dehant;J. Hinderer
共振由于近昼夜的自由摆动，观察到在昼夜田潮汐和相关的章动，用于确定频率和阻尼的摆动。将数据堆叠以提供共振参数的最小二乘估计：频率、品质因数和复数强度。以前的一些论文提出了使用潮汐或章动数据集进行同样的分析;在这两种情况下，频率约为−（1 + 1/435）周/恒星日，但章动数据的品质因子大于潮汐数据。本文同时分析了这两组数据，并着重讨论了自由核章动周期和品质因子的确定。我们分析了国际地球潮汐中心（ICET）提供的一系列潮汐数据集，章动数据集从出版物中收集。我们的最终结果是从一个全球叠加使用四个独立的章动数据集和三个超导重力仪数据集在一起。拟合参数的值为λFCN =-（1 + 1/（434.1 ± 0.9））周/恒星日和Q 54，000（36，000; 109，000）。
The resonance due to the nearly diurnal free wobble, observed in the diurnal tesseral tides and in the associated nutations, is used to determine the frequency and the damping of this wobble. The data are stacked to provide a least squares estimation of the resonance parameters: frequency, quality factor, and complex strengths. Some previous papers presented the same kind of analysis using either tidal or nutation data sets; in both cases, the frequency was about −(1 + 1/435) cycle/sidereal day, but the quality factor was larger for nutation data than for tidal data. In this paper we analyze simultaneously both sets of data, and we focus our attention on the determination of the free core nutation period and quality factor. We have analyzed a series of tidal data sets provided by the International Center for Earth Tides (ICET), and nutation data sets gathered from published matter. Our final result is obtained from a global stacking using four independent nutation data sets and three superconducting gravimeter data sets together. The values of the fitted parameters are found to be λFCN = −(1 + 1/(434.1 ± 0.9)) cycle/sidereal day and Q ≃ 54,000 (36,000; 109,000).