利用改进的SRTI法研究中尺度电离层行波扰动

Research on medium-scale traveling ionospheric disturbances using a modified SRTI method

针对现有单站电离层行波扰动指数(Single Receiver TID Index,SRTI)探测中尺度电离层行波扰动时探测周期范围有限的问题,本文提出了一种改进的SRTI方法,以提高探测扰动周期的适用范围.介绍了利用SRTI和改进的SRTI探测中尺度电离层行波扰动的原理,从理论上分析比较了二者探测扰动周期范围的能力,并采用美国加州南部的5个IGS站2012年年积日189的GPS观测数据,对电离层扰动进行了分析.结果显示在21∶30—23∶00LT时,扰动观测序列存在周期为15min和39min的扰动波,但是现有SRTI方法只探测到了前者,而改进的SRTI法很好地探测到了两个周期的扰动波,表明其对短周期和较长周期的扰动均具有较好的灵敏性.利用改进的SRTI法计算的扰动观测序列,应用傅里叶变换相位差分法估计了电离层扰动的传播参数,其结果总体上与前人研究成果一致,这表明改进的SRTI法完全可以应用于电离层行波扰动的研究中,而且由于计算简单,在处理大量数据时具有一定优势.

Considering the limit of the single receiver TID index （SRTI） method in detecting medium-scale traveling ionospheric disturbances （MSTIDs）, this work proposes a modified SRTI method to expand the detectable period scope. The principles of SRTI method and modified SRTI method are presented and detectable period range is analyzed theoretically for both methods. Then we analyze MSTIDs using observation data of 5 IGS stations in southern California on day 189, 2012. The results show that there are two disturbance waves with the period 15 min and 39 min, respectively at 21：30-23：00 LT. The SRTI method detected only the former, while the modified SRTI method propped both of them, which means it has good sensitivity to both short- period disturbances and long-period disturbances. With the disturbance sequence acquired by the modified SRTI method, the MSTIDs propagation parameters are estimated using the FFT phase difference method. The results are consistent with the previous studies totally. This indicates that the modified SRTI method can be fully applied to the study of MSTIDs and has advantage in processing mass data with a simple calculation procedure.