基于welch功率谱估计的地磁GM4秒数据频段分析

GEOMAGNETIC DISTURBANCE FREQUENCY BANDS ANALYSIS OF GEOMAGNETIC GM4 SECONDS DATA BASED ON WELCH METHOD

基于welch算法的经典功率谱估计对新疆区域内乌鲁木齐台、喀什台和且末台的3台GM4磁通门磁力仪磁扰日时段的秒数据进行分析。实验首先分别对3台GM4秒数据的高频数据进行FFT分析,磁扰日时段3台GM4秒数据受磁扰较为明显的频段均集中在0. 005～0. 025 Hz,此频段内振幅较大,突跳点较多。实验基于welch算法的功率谱估计对3台GM4秒数据进行功率谱分析,频率域采用受磁扰较为集中的频段,结果表明:3台GM4秒数据受到的干扰主要为地磁场的高频部分,干扰的频段范围集中在0. 002～0. 006 Hz内,H分量数据波动较大,在该频段内数据曲线出现毛刺和高频震荡现象; D分量在此频段内有轻微波动; Z分量数据整体较为平滑,受扰最小。

This paper analyzed geomagnetic GM4 seconds data from Urumqi station, Kashi station and Qiemo station of Xinjiang taking geomagnetic disturbance frequency bands based on Welch method. First, FFT analysis about high frequency part of GM4 seconds data was carried out in experiment. We found the dominant frequency bands was 0. 005 Hz - 0. 025 Hz dining the magnetic disturbance time. The amplitude was larger and more jumping points came out in this frequency band. Second, power spectrum analysis was carried out based on Welch algorithm. In frequency domain, more concentrated frequency bands were used. Results showed thatthe high frequency part of geomagnetic field mainly provoked the interference of GM4 seconds data. The frequency range of interference was concentrated in the range of 0. 002 Hz to 0. 006 Hz. The horizontal component signals of GM4 second data fluctuated greatly, and the data curve glitched and presented high frequency oscillation phenomenon in this frequency band; the declination component signals of GM4 second data had slight fluctuation in this frequency band; the vertical of GM4 second data was relatively smooth and the disturbance was the smallest of these three component signals.