Dynamic Characterization of Equatorial Plasma Bubble Based on Triangle Network‐Joint Slope Approach

• Published in: Journal of geophysical research. Space physics 2024-08, Vol.129 (8), p.n/a
• Main Authors: Miao, Xirui, Yang, Rong, Fu, Naifeng, Zhan, Xingqun, Morton, Y. Jade
• Format: Article
• Language: English
• Subjects: Algorithms; Bubbles; Color; Data analysis; Drift estimation; drift velocity; Electron density; equatorial plasma bubble(EPB); Geomagnetic storms; Geomagnetism; Global navigation satellite system; Global positioning systems; GPS; Image processing; Ionospheric disturbances; Magnetic properties; Magnetic storms; Monitoring; Navigation satellites; Navigation systems; Outliers (statistics); Plasma bubbles; Resampling; ROT; Satellite navigation systems; Satellite observation; Satellites; Slopes; Statistical analysis; Storms; time difference of arrival (TDOA); Total Electron Content; triangle network‐joint slope (TN‐JS); Triangulation
• ISSN: 2169-9380; 2169-9402
• DOI: 10.1029/2024JA032912

This paper introduces a Triangle Network‐Joint Slope (TN‐JS) approach to characterize the spatial and temporal dynamics of Equatorial Plasma Bubbles (EPBs) during geomagnetic storms. To collaboratively determine the EPB drift directions from multiple stations, a Delaunay triangle network is constructed, utilizing the distribution of Ionospheric Piercing Points (IPPs). The Time Difference of Arrival (TDOA) is extracted through cross‐correlating the Rate of Total Electron Content (ROT). The EPB drift direction can be approximately calculated by considering TDOA and IPP distances within each individual triangle of the network. This calculation is then refined through a joint statistical analysis. Using a reference station as the origin, the remaining stations within the network are projected along the estimated EPB drift direction. A spatial‐temporal color map illustrating regional ionospheric anomaly ROT observations is constructed. The EPB drift velocity among multiple stations can be collectively estimated by fitting the slope of this map, facilitating outlier exclusion. Accounting for satellite dynamic effects and the diverse orbit characteristics of GPS and BDS, corresponding IPP scan velocity compensation is performed and analyzed for EPB dynamic estimation. Using the geomagnetic storm event that occurred on September 8 as a case study, the spatial‐temporal kinetic properties of EPBs is characterized by analyzing Global Navigation Satellite System (GNSS) observations from 17 Hong Kong monitoring stations with the proposed TN‐JS approach. The results indicate during this magnetic event, that EPBs exhibit a westward drift trend with velocities ranging from a few tens to hundreds of meters per second in GPS and BDS observations. Plain Language Summary Total Electron Content (TEC) is a path integrated electron density and its rate (ROT) of change reflect the ionospheric disturbance during magnetic storms. This article introduces a new method called Triangle Network‐Joint Slope (TN‐JS) to study the movement of Equatorial Plasma Bubbles (EPBs). TN‐JS uses a network of GNSS monitoring stations to determine the drift velocity of EPBs. By resampling ROT correlation using triangulation along the drift direction, TN‐JS transforms traditional EPB dynamic estimation into image processing of the color‐coded ROT maps. The TN‐JS algorithm is tested with data collected from 17 monitoring stations around Hong Kong during a geomagnetic storm on 8 September 2017 to show EP