摘要
本文用哀减谐振模型讨论了大气角动量共振引起的日长近50天的变化,这种模型由共振周期和品质因子Q来描述其状态.我们用自迥归和自迥归移动平均时间序列模型拟合日长和大气角动量资料序列,得到Q和共振周期的估计值.这种方法得到的周期值约为50天.因为Q值比较小,说明共振度是小的.要想得到精确的周期值大概是不可能的.
The changes in the length of day with periods near 50 days appear to be driven by resonances in atmospheric angular momentum. We use a damped harmonic oscillator model which is described by a resonant period and a quality factor Q to describe this behavior. Estimates of Q and the resonant period have been obtained by fitting auto regressive and auto regressivemoving average time series models to length of day and atmospheric angular momentum data. This technique yields estimates of the period which are near 50 days, but suggests that a precise value for the period is probably not obtainable because the low Q values indicate that the degree of resonance is slight.
出处
《天文学报》
1987年第1期29-38,共10页
Acta Astronomica Sinica
