In this paper,Changli station in Hebei Province was taken as an example,in which the minute data of geomagnetic Z component was used to analyze the spectral values of its main frequencies during normal time,geomagneti...In this paper,Changli station in Hebei Province was taken as an example,in which the minute data of geomagnetic Z component was used to analyze the spectral values of its main frequencies during normal time,geomagnetic storm time and low point displacement time interval respectively. After fitting of ten high spectral values to loga-rithmic functions,it is found that,by using same length of data,the spectral values at geomagnetic storm time in-crease apparently compared with those at normal time,especially at the high frequency segment. While low point displacement occurred,the spectral values at high frequency are approximate to those at normal time,but at period above 4 hours they are mostly lower than those at normal time. Comparison of accumulating of some FFT results at low point displacement and normal time shows that,spectral values at periods of 8.5 and 13.7 hours increase at low point displacement time relative to those at normal time. Compared with the images of Ne observed at DE-METER satellite,it is illustrated that the occurrence of geomagnetic low point displacement is well corresponding with the increase of Ne in ionosphere. Finally it was discussed about those spectral features and the occurrence mechanism of geomagnetic low point displacement.展开更多
地磁活动指数(D_(st))不仅是监测空间天气活动的重要参数,也是地震电磁研究中作为排除来自空间天气的"非震"信号的重要参数(Le et al,2011)。D_(st)指数计算简便,具有连续性和时序性较好的优势,但其物理意义复杂,不能完全反...地磁活动指数(D_(st))不仅是监测空间天气活动的重要参数,也是地震电磁研究中作为排除来自空间天气的"非震"信号的重要参数(Le et al,2011)。D_(st)指数计算简便,具有连续性和时序性较好的优势,但其物理意义复杂,不能完全反映磁暴过程,且存在计算误差以及数学意义不明确等问题。展开更多
基金National Science and Technology Program (2006BAC011302-04-02)Basic Research Project in Institute of Earthquake Science,China Earthquake Administration.
文摘In this paper,Changli station in Hebei Province was taken as an example,in which the minute data of geomagnetic Z component was used to analyze the spectral values of its main frequencies during normal time,geomagnetic storm time and low point displacement time interval respectively. After fitting of ten high spectral values to loga-rithmic functions,it is found that,by using same length of data,the spectral values at geomagnetic storm time in-crease apparently compared with those at normal time,especially at the high frequency segment. While low point displacement occurred,the spectral values at high frequency are approximate to those at normal time,but at period above 4 hours they are mostly lower than those at normal time. Comparison of accumulating of some FFT results at low point displacement and normal time shows that,spectral values at periods of 8.5 and 13.7 hours increase at low point displacement time relative to those at normal time. Compared with the images of Ne observed at DE-METER satellite,it is illustrated that the occurrence of geomagnetic low point displacement is well corresponding with the increase of Ne in ionosphere. Finally it was discussed about those spectral features and the occurrence mechanism of geomagnetic low point displacement.
