Detection of Equatorial Plasma Bubbles Using the COSMIC‐2 Rate of TEC Index

Abstract Equatorial plasma bubbles (EPBs) are large‐scale plasma depletion structures that can disrupt Global Navigation Satellite Systems (GNSS) and other space‐based technologies. Several instruments have been employed to study EPB dynamics, with Total Electron Content (TEC) and Rate of TEC change Index (ROTI) data standing out as valuable parameters for studying their climatology. While ground‐based GNSS networks provide significant insights, their spatial coverage, particularly over oceanic regions, is limited. This highlights the importance of satellite missions such as COSMIC‐2, designed to analyze the Earth's ionospheric plasma. The topside TEC data from COSMIC‐2 offers an opportunity to monitor plasma structures from a different point of view. In this study, we assess the effectiveness of ROTI derived from COSMIC‐2 topside TEC observations in detecting and mapping EPB signatures during the ascending and maximum phases of the solar cycle 25 (2020–2025). Topside EPB occurrence was identified using a ROTI threshold of ≥0.11 TECU/min, a value established by correlating ground‐ and satellite‐based GNSS observations. To validate this definition, we conducted a climatological analysis to evaluate whether the EPB detections aligned with expected local time, latitude, longitude, and seasonal variations. The results demonstrate that COSMIC‐2 ROTI effectively captures the spatial and temporal evolution of EPBs and confirms the robustness of the COSMIC‐2 ROTI index for climatological studies, underscoring the role of Low Earth Orbit (LEO) constellations in complementing traditional GNSS networks.