Multi‐instrumental Observations of the Quasi‐16‐Day Variations From the Lower Thermosphere to the Topside Ionosphere in the Low‐Latitude Eastern Asian Sector During the 2017 Sudden Stratospheric Warming Event
Jing Liu, Donghe Zhang, Yongqiang Hao, Zuo Xiao
Abstract
Abstract Variations of the low‐latitude ionosphere in the eastern Asian sector during the 2017 sudden stratospheric warming (SSW) were studied with multi‐instrumental observations that correspond to different altitudes. Specifically, the variations of the topside ionosphere as high as over 830 km were investigated with data from the Swarm B satellite (~500 km), the Defense Meteorological Satellite Program F15 satellite (~830 km), and the Meteorological Operational satellite‐A (~830 km). The main results are as follows. (1) Simultaneous variations were detected in the ionospheric parameters from the E region to the topside ionosphere around the first peak warming of the 2017 SSW. (2) These variations exhibited similar quasi‐16‐day (Q16D; ~14.5‐day) periods, and these periods were most significant just before the first peak warming. (3) These simultaneous Q16D variations were not due to the solar extreme ultraviolet irradiance or geomagnetic activities but were probably driven from below, by planetary waves or semidiurnal lunar tides that enhanced during the SSW. (4) The Q16D variation of the topside ionospheric electron density at ~830 km was probably driven not only by the upward mapping electric field modulated in the E region dynamo but also by the electric field modulated in the F region dynamo.