Multivariate Analysis on the Ionospheric Responses to Planetary Waves During the 2019 Antarctic SSW Event

Abstract

AbstractA rare minor sudden stratospheric warming is observed in the Antarctic polar region during September 2019, which results in the enhancement of a westward wavenumber 1 quasi‐6‐day wave (Q6DW) in the mesopause region. The impacts of this Q6DW event to the ionosphere are then comparatively investigated with multiple data sets, including the ground‐based total electron content (TEC) from geostationary BeiDou satellite receivers and F2 layer maximum frequency (foF2) from ionosondes ranging from 20 to 40°N over eastern Asia. Besides, the global TEC maps from the International Global Navigation Satellite Systems Service (IGS) are also utilized to study the longitudinal variations. The ground‐based TEC and foF2 observations clearly shows planetary wave (PW) signals with a similar period as those in the mesosphere, which are further verified to be westward with zonal wavenumber 1 by IGS TEC maps. The ground‐based TEC and foF2 also show that the peak of the ionospheric response is at around 1,200–1,400 LT and 25°N over eastern Asia with maximum amplitudes of ∼9 TECU and ∼1.5 MHz, respectively, which are also well captured by IGS TEC maps. Nevertheless, the wave amplitudes exhibited by ground‐based TEC are 2–3 times larger than that in IGS TEC. Besides, the IGS TEC map shows that the ionospheric oscillations at different longitudes peak in the equatorial ionospheric anomaly crest region at similar solar local time, but with significant variabilities in their amplitude. Our analysis shows that the ground‐based ionospheric observations and IGS TEC maps generally exhibit consistent latitudinal structures on the neutral‐ion coupling through PWs.