Statistical Study of Global Lightning Activity and Thunderstorm‐Induced Gravity Waves in the Ionosphere Using WWLLN and GNSS‐TEC

Abstract

AbstractWe present a statistical study of global lightning activity and correlate this activity with ionospheric fluctuations in the Total Electron Content (TEC). Thunderstorms play a significant role in modulating the ionosphere's plasma distribution. Using the well‐known World Wide Lightning Location Network (WWLLN) system, we investigate the diurnal, monthly, and seasonal variations in lightning stroke numbers across six continents. Typically, the monsoon causes a significant increase in lightning occurrences, as reflected in the WWLLN observations. We chose a time frame of July–December 2019, which usually covers the peak and post‐monsoon seasons on all the continents. The diurnal lightning activity is observed to be highest in the early afternoon for all the locations. In addition, we observe hemispherical changes in lightning activity that appear opposite in nature. Using the Global Navigation Satellite System (GNSS)‐International GNSS Service data, we use the Vertical TEC (VTEC) and Rate of change Of TEC Index as proxies for the amplitude scintillation S4 index. Using the wavelet analysis of the small‐scale fluctuations in the VTEC profile, we provide a time series analysis of wave‐like TEC fluctuations alongside lightning stroke count as a proxy for thunderstorm activity. It is found that, in most cases, Traveling Ionospheric Disturbances (TIDs) or a local maximum of small‐scale fluctuation in VTEC (dVTEC) that could be coupled to atmospheric gravity waves are observed during periods of peak thunderstorm activity. Most of the locations show that the spectral power of TIDs and the stroke energy density are highly correlated.