| 基于改进STI方法的外源磁场垂直分量动力非平稳性分析 |
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| 引用本文： | 卢世坤,李夕海,牛超.基于改进STI方法的外源磁场垂直分量动力非平稳性分析[J].空间科学学报,2014,34(3):278-286. |
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| 作者姓名： | 卢世坤 李夕海 牛超 |
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| 作者单位： | 第二炮兵工程大学 西安 710025 |
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| 基金项目： | 国家自然科学基金项目(41374154,40974037);中国博士后科学基金特别项目(2012T50882);中国博士后科学基金面上项目(201150M1554)共同资助 |
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| 摘 要： | Space Time-Index（STI）方法是一种验证时间序列中是否存在非平稳性的图示方法. 利用改进的STI方法可以定量分析外源磁场垂直分量z的非平稳性特征. 以不同地磁指数（K=0，2，4，6）、不同Lloyd季节和昼夜外源磁场z分量为对象进行对比分析. 结果表明，改进的STI方法能够有效检验外源磁场的非平稳特性，且z分量为非平稳时间序列；不同K指数的z分量分析表明，随着K指数的增加，z分量的相空间分布越来越不均匀，时间演化特征越来越复杂；不同Lloyd季节的分析表明，各季节的STI图较为相似，但随着日地距离的减小，z分量时间演化特征的复杂性增强，呈现出一定季节变化特征；对昼夜变化的分析可知，夜晚z分量STI图的波动性比白天要强，昼夜变化特征较为明显.
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| 关 键 词： | 外源磁场 Space Time-Index 非平稳性 时间演化特征 |
| 收稿时间： | 2013-05-15 |
Test of the Dynamical Non-stationarity in Geomagnetic Variation Field Based on Improved Space Time-Index Method |
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| Affiliation: | Second Artillery Engineering University, Xi'an 710025 |
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| Abstract: | Space Time-Index (STI) plots is a graphical method used for testing dynamical non-stationary in general time series. In this paper, the non-stationary characteristics of the z components of geomagnetic field variations with the improved Space Time-Index (STI) plots method were analyzed, and data under different K indexes, different Lloyd seasons, as well as day and night are used. The result shows that the improved space time-index plots method can effectively test whether dynamical non-stationarity exists in geomagnetic variation field, and there is dynamical non-stationarity in z component. On the other hand, the analysis of the z component from different K-indexes introduces that, with the increase of K-index, the phase space distributions of z component become increasingly more uneven and the time evolution features become more complex. Research on geomagnetic field variation from different Lloyd seasons presents that the shapes of the STI plots of z component from different Lloyd seasons are similar. However, as the decrease of the Sun-Earth distance, the complexity of the time evolution of z component becomes heightened, showing some seasonal variations. And the conclusion obtained from the study of diurnal variation of geomagnetic field is that, fluctuation of the STI plots of z component in night time is more severe than that in daytime, and the diurnal variation of z component is obvious. |
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