Ionospheric Response to the 2018 Sudden Stratospheric Warming Event at Middle‐ and Low‐Latitude Stations Over China Sector

Abstract

The total electron content (TEC) recorded at two middle-latitude stations (Mohe and Beijing), and four low-latitude stations (Xiamen, Guangzhou, Nanning, and Kunming) in the China sector are analyzed to study the response of the ionosphere during the sudden stratospheric warming (SSW) event in February 2018. The TEC and deviation of TEC (ΔTEC) present remarkable perturbation after the reversal of the zonal wind during the SSW period. The ΔTEC presents enhancement during the daytime and decreases after sunset, especially around the temperature peak. Results of wavelet power spectra analysis show that the ΔTEC shows intensive semidiurnal and diurnal oscillations during the SSW period. The percentage of dTEC exhibits moderate correlation with solar geophysical drivers (such as solar wind speed, F 10.7 , and Ap index) during the period of 11-26 February at low-latitude stations. The significant correlation between equatorial electrojet and the percentage of dTEC monitored at low latitude indicates that the equatorial electrojet plays a key role in the anomaly perturbation and periodic oscillation of TEC, while it has a weak correlation at middle latitude.

Comparison of stratospheric evolution during the major sudden stratospheric warming events in 2018 and 2019

“…In general, planetary wave activities are considered a significant driver of the atmospheric dynamics during SSWs (e.g., Azeem et al, 2005; Goncharenko et al, 2012; Shi CH et al, 2017; Cao C et al, 2019). The vortex types during SSWs are believed to be connected to the dominant planetary waves in the prewarming periods; that is, wave 1 plays a primary role in displacement events, whereas wave 2 dominates in split events (e.g., Harada and Hirooka, 2017; Liu SM et al, 2019). To further understand the wave evolution during the 2018 and 2019 SSWs, the day‐to‐day amplitudes of the SPWs with wavenumber 1 (SPW1), wavenumber 2 (SPW2), and wavenumber 3 (SPW3) were calculated at pressure levels of 10 hPa based on the geopotential height at 60°N.…”

“…Recently, in 2018 and 2019, two major SSWs occurred continuously during the Arctic winters (e.g., Rao J et al, 2018, 2019b, 2020). The 2018 SSW, with a central date of 12 February 2018, was found to be related to the extremely cold winter over the European region (King et al, 2019; Lü ZZ et al, 2020) and ionospheric perturbations over the China sector (Liu GQ et al, 2019). The 2018 SSW was excited by the upward wavenumber 2 planetary waves, which were mainly related to the Ural and Alaska blockings (Rao J et al, 2018).…”

African and American Equatorial Ionization Anomaly (EIA) Responses to 2013 SSW Event

“…Both the TEC and ΔTEC are measured in TEC unit (TECU), where 1 TECU = 10 16 el/m 2 . The Δ TEC defines ionospheric variations caused by different phases of SSW in comparison with the quiet‐time condition (Liu et al., 2019; Paes et al., 2014).…”

Study of a Quasi 4‐Day Oscillation During the 2018/2019 SSW Over Mohe, China

“…It is well known that the SSW event occurs due to the interactions between stationary planetary wave enhancement and the zonal mean flow (Matsuno, 1971). SSW, as a reoccurring atmospheric event in the Northern Hemisphere winter, has significant influences on the global atmospheric energy transfer and causes different scales of fluctuations in the atmosphere and ionosphere (e.g., Chau et al, 2009Chau et al, , 2012Goncharenko et al, 2013;Gong et al, 2013Gong et al, , 2016Karpechko et al, 2017;Liu et al, 2019;Pancheva & Mukhtarov, 2011;Sofieva et al, 2012).…”