Study on the Ionospheric Response Mechanisms to Nocturnal Rocket Launches: Multi‐Source GNSS Observational Evidence From the Long March 3B Case

Utilizing the unique opportunity of the Long March 3B rocket launch on 1 August 2024 at 13:14 Universal Time (UT), this study integrated global satellite navigation system (GNSS) data from the Crustal Movement Observation Network of China (233 stations), the China Earthquake Administration's Sichuan‐Yunnan National Earthquake Monitoring and Forecasting Test Site (140 stations), and the Taiwan Dense Network (123 stations). By leveraging the static observation characteristics of BeiDou GEO satellites and employing Savitzky‐Golay filtering to extract ionospheric total electron content (TEC) anomaly signals, it systematically revealed the dynamic evolution process of nighttime ionospheric disturbances. The results indicate that: (a) The disturbances exhibited a three‐stage evolution: an initial weak negative disturbance (dominated by chemical depletion) appeared 13 min after launch, developed into multi‐scale traveling ionospheric disturbances (TIDs) with propagation speeds of 700–1,320 m/s and periods of 10–15 min between 13 and 45 min after launch, and completely attenuated after 14:15 UT. (b) Under nighttime conditions, the dense GNSS networks clearly captured a V‐shaped wavefront TID structure triggered by the rocket exhaust plume/flight‐induced shock wave, with coverage extending to the Taiwan region and the Philippine Sea. (c) BeiDou GEO observations captured the “snowplow effect” at night, characterized by localized TEC enhancement at the edges of the depletion region. This study reveals the unique response mechanisms of the nighttime ionosphere to rocket launch activities, providing crucial evidence for improving atmospheric wave propagation models and enhancing the interference resistance capabilities of space information systems.