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

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.