IROTI: a new index to detect and identify traveling ionospheric disturbances and equatorial plasma bubbles

The rate of total electron content index (ROTI), as the most common ionospheric disturbance index, is often used to detect equatorial plasma bubbles (EPBs). But it cannot effectively identify traveling ionospheric disturbances (TIDs). This research firstly proposes a new ionospheric disturbance index named the time integral and rate of the total electron content index (IROTI), which can be used to detect and classify TIDs and EPBs. Several hundreds of the TIDs and EPBs events from 2010 to 2020 are used to validate and prove the validity of the new proposed index. The experimental results demonstrate significant benefits over other methods in that the IROTI can detect and recognize EPBs as well as large-scale TIDs and medium-scale TIDs during geomagnetic quiet and storm days. According to statistical results, IROTI can successfully detect 84.3% of the TIDs events during the tested period, while ROTI is able to detect only 8.26% of that and proved that it can be used to distinguish between TIDs and EPBs. Finally, the thresholds of IROTI for separating these two kinds of ionospheric disturbance events were determined. When IROTI is greater than 7.28 TECU 2 , the type of ionospheric disturbance is considered to be EPBs. And when IROTI is less than 4.91 TECU 2 , the type of ionospheric disturbance is determined to be TIDs event. It is worth noting that in some cases, further excitation mechanism analysis and other detection instruments are recommended to be incorporated to assist IROTI for more precise detection and classification of TIDs and EPBs.