Statistical Observation of Thunderstorm-Induced Ionospheric Gravity Waves above Low-Latitude Areas in the Northern Hemisphere

Abstract

Gravity waves (GWs) generated in the lower atmosphere can propagate upwards to ionospheric height. In this study, we investigated the correlation between ionospheric GWs detected by Global Navigation Satellite System (GNSS)-derived total electron content data and thunderstorm events recorded by a local lightning-detection network in the low-latitude region of Southern China during a four-year period, from 2014 to 2017. Ionospheric GWs were detected on both thunderstorm and non-thunderstorm days. Daytime ionospheric GW activity on high-thunderstorm days showed a similar convex-function-like diurnal variation to thunderstorm activity, which is different to the concave-function-like pattern on non-thunderstorm days. Daytime ionospheric GW activity on low-thunderstorm days showed an approximately linear rising trend and was of a larger magnitude than that of high-thunderstorm days, suggesting it may be mixed by non-thunderstorm origins. Night-time enhancement of ionospheric GW activity was observed on thunderstorm days but not on non-thunderstorm days. Furthermore, ionospheric GW activity on thunderstorm days showed a positive correlation to solar activity. These findings can effectively distinguish thunderstorm-related ionospheric GWs from those of non-thunderstorm origins and provide more comprehensive knowledge of thunderstorm-ionosphere coupling in low-latitude areas.

Evaluating Total Electron Content (TEC) Detrending Techniques in Determining Ionospheric Disturbances during Lightning Events in A Low Latitude Region

“…the HK SatRef are quite close; hence, similar observations are made by most stations at a given time [14]. Only observations from station HKOH meeting the criteria in Section 2.4 are presented.…”

“…Mahmud M [13], who also studied thunderstorm events over Southern Africa, showed that a strong correlation exists between hourly lightning and ionosphere irregularity event occurrence. Recent studies by Tang, et al [14] and Liu, et al [15] showed the characteristics of thunderstorm generated ionosphere gravity waves (IGW) in the Southern China region.…”

Significant Day-time Ionospheric Perturbation by Thunderstorms along the West African and Congo Sector of Equatorial Region

“…However, our work is based on direct measurement of TEC above thunderstorm events and their responses, with more focus on the gravity wave effects. Although a recent contribution by Tang et al (2019) focused on the contribution of gravity wave, however, their work only covers the low latitude region from ~14°N to 25°N close to Hong Kong and its surroundings, which is far greater 1500 km from low latitude/equatorial region 17 . It is therefore pertinent to consider investigations around the low/latitude equatorial region, considering the fact that the ionospheric processes, dynamics and responses to external influence vary with proximity to the equator.…”

Study on Seasonal Variations of Plasma Bubble Occurrence over Hong Kong Area Using GNSS Observations

“…As seen in Figure 9, thunderstorm activity during the summer solstice was significantly stronger than during the winter solstice. Tang et al [29] analyzed the relationship between thunderstorms and the ionospheric GWs over the Hong Kong area during the years of 2014-2017. Their research indicated that thunderstorm events were the main source of GWs, especially during high thunderstorm days, such as the summer solstice.…”

“…According to the local VLF detection network, the Hong Kong area had frequent thunderstorm activity during March-October. Using the processing method in Tang et al [29], we obtained the average thunderstorm coverage area (grid counts) for different seasons during each year from 2014 to 2017, shown in Figure 9. As seen in Figure 9, thunderstorm activity during the summer solstice was significantly stronger than during the winter solstice.…”