中文摘要：

使用相关方法和welch法计算功率谱密度研究汶川地震前后GPS TEC在时域和频域上的变化,并进一步分析N_mF2空间分布变化.得出主要结论,震前5月9日开始TEC平常具有良好的相关性被打破,24 h全日波、12 h半日波成分功率谱密度幅度值变化明显.5月12日至6月11日N_mF2变化幅度明显增大.研究结果显示,TEC和N_mF2时空分布变化存在电离层震前扰动和同震响应,并且TEC震后的异常变化相比震前更加显著.表明使用的方法可以有效检测到地震发生前后电离层异常扰动信号.

英文摘要：

The study provides a TEC data processing method by correlation analysis and power spectral density analysis. We investigated the variation of the TEC data in time domain and frequency domain and discussed their relationship with Wenchuan earthquake. At the same time, we analyzed the spatial distribution variation of NmF2. It was found that the correlation coefficients have various degrees of change for each station on 9 May 2008, and the usual good correlation is broken. The TEC power spectrum amplitudes of 24h diurnal wave and 12h semi- diurnal wave changed significantly in the period of earthquake occurrence. The amplitude of NmF2 variation increased significantly from February 12 to June 11. Spatial and temporal distribution variation of TEC and NmF2 showed ionospheric disturbances prior to the Wenchuan earthquake and co-seismic response, and the anomalous variation of TEC is more significant after the earthquake. The above results showed that the method can effectively detect the anomalous variation of ionosphere before and after earthquake.