Multi-scale ionosphere responses to the May 2017 magnetic storm over the Asian sector

• Published in: GPS solutions Vol. 24; no. 1
• Main Authors: Liu, Lei, Zou, Shasha, Yao, Yibin, Aa, Ercha
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 2020; Springer Nature B.V
• Subjects: Atmospheric Sciences; Automotive Engineering; Blob theory; Coronal mass ejection; Defense programs; DMSP satellites; Earth and Environmental Science; Earth Sciences; Electric fields; Electrical Engineering; Electron density; Electron density profiles; Geomagnetism; Geophysics/Geodesy; Global navigation satellite system; Ground-based observation; Interplanetary magnetic field; Ionosphere; Ionospheric propagation; Magnetic fields; Magnetic storms; Meteorological satellites; Meteorology; Multiscale analysis; Navigation satellites; Original Article; Penetration; Plasma density; Radio occultation; Recovery; Satellite constellations; Satellite observation; Space Exploration and Astronautics; Space Sciences (including Extraterrestrial Physics; Storms; Blob structure; Geomagnetic storm; Positive and negative ionosphere responses; TID
• ISSN: 1080-5370; 1521-1886
• DOI: 10.1007/s10291-019-0940-1

We investigate multi-scale ionospheric responses to the May 27, 2017, geomagnetic storm over the Asian sector by using multi-instrumental observations, including ground-based global navigation satellite systems (GNSS) network, constellation observing system for meteorology, ionosphere and climate radio occultation, the FengYun-3C (FY-3C) GNSS occultation sounder electron density profiles and in situ plasma density observations provided by both Swarm and defense meteorological satellite program missions. This geomagnetic storm was an intense storm with the minimum symmetric horizontal component reaching − 150 nT and was caused by a coronal mass ejection released on May 23. The main observations are summarized below: (1) two ionospheric positive storm periods were observed. The first one was observed in the noon–afternoon sector during the main phase of the storm on May 28, with nearly 120% TEC enhancement. The second one was of a smaller scale and occurred on the nightside during the recovery phase of the storm on May 29. The first dayside positive storm was initiated by the interplanetary magnetic field (IMF) Bz southward turning and eastward penetration electric field, while the second nightside one was terminated by a later southward turning of the IMF Bz since the Asian sector was on the nightside and the penetration electric field changed westward. (2) A negative storm occurred from 00:00 to 12:00 UT on May 30 over the Asian sector, nearly 2 days after the main phase, which was due to the thermospheric composition change, i.e., decrease in the O/N
2
ratio, as shown in the TIMED/GUVI measurements. (3) A band-like TEC enhancement was observed aligning in the northwest–southeast direction and propagated slowly southwestward from 15:00 to 20:00 UT (23:00–04:00 LT, near midnight) on May 28 during the recovery phase of the storm. In situ density observations from the Swarm B and DMSP F15&16 satellites confirmed the density enhancement at 510 km and 850 km, respectively, and revealed that this band-like TEC enhancement structure resembles the so-called plasma blob. The similarities of the observed plasma blob characteristics in terms of spatial structure, propagation trend and temporal evolution with the nighttime traveling ionospheric disturbance (TID) are consistent with the TID-blob theory.