[P-EM12] Coupling Processes in the Atmosphere-Ionosphere System

[PEM12-18] GNSS remote sensing of man-made space weather events on consecutive days over East Asia during January 2024

*Lin Charles¹、Rajesh P. K.¹、Saito Susumu²、Huba Joseph³、Huang Tzu-Jui¹、Shen Mitchell⁴、Chou Min-Yang^5,6、Yue Jia^5,6、Lin Chi-Yen⁷ (1.Department of Earth Sciences, National Cheng Kung University、2.Electronic Navigation Research Institute, National Institute of Maritime, Port and Aviation Technology, Tokyo, Japan、3.Syntek Technologies Inc., Fairfax, VA, USA、4.Princeton University, Princeton, NJ, USA、5.NASA Goddard Space Flight Center, Greenbelt, MD, USA.、6.Physics Department, Catholic University of America, Washington, DC, USA、7.Center for Astronautical Physics and Engineering, National Central University, Taoyuan, Taiwan)

キーワード：Rocket Exhaust Depletion、Concentric Traveling Ionosphere Disturbances、Ionosphere Disturbances、GNSS Observation

The maiden launch of Gravity-1, labelled as the most powerful all-solid propellent rocket yet, on 11-January-2024 around 0530 UT from an offshore launch platform, Yellow-Sea, China by OrienSpace was followed by the 48^th launch of H-IIA rocket from Tanegashima space center by Japanese Aerospace Exploration Agency at 0444 UT the next day. These rare launches on consecutive days over similar geographical regions and local-times yielded rocket-induced concentric traveling ionospheric disturbances (CTIDs) and depleted total electron content (TEC) by 50-70% (20-60 TEC units (TECU) reduction). The CTIDs with periods 9-11 minutes and wavelengths 300-720 km propagated at speeds of 300-1100 m/s, displaying acoustic dispersion characteristics. The TEC depletions covering a region of 3.5-4.5°, lasted for 60-90 minutes before eventually recovering. Three-dimensional Global Ionospheric Specification (GIS) electron density profiles and TEC tomography inversions indicate ionospheric depletions over 250-320 km altitudes. The observed rate of TEC depletions during the two events are used to compare the water molecule (H₂O) content in the combustion exhausts of the two rockets by using SAMI2 (Sami2 is another model of ionosphere) simulations. The results show that Gravity-1 emitted only 5-7% of the H₂O contained in H-IIA exhaust, while the rapid occurrence of TEC depletion covering a wider spatial area is indicative of its relatively steeper trajectory. The observations are further used to estimate the possible delay due to the TEC gradients by solving the carrier-phase ambiguity over selected stations. The results indicate a delay gradient of up to 60mm/km, much smaller to threaten ground-based augmentation systems (GBAS).