Evolution of Global Lightning in the Transition From Cold to Warm Phase Preceding Two Super El Niño Events

Abstract

Multistation observations of Schumann resonance (SR) intensity document common behavior in the evolution of continental‐scale lightning activity in two super El Niño events, occurring in 1997/98 and 2015/16. The vertical electric field component of SR at Nagycenk, Hungary and the two horizontal magnetic field components in Rhode Island, USA in 1997, and in 2014–2015, the two horizontal magnetic field components at Hornsund, Svalbard and Eskdalemuir, United Kingdom as well as in Boulder Creek, California and Alberta, Canada exhibit considerable increases in SR intensity from some tens of percent up to a few hundred percents in the transition months preceding the two super El Niño events. The UT time distribution of anomalies in SR intensity indicates that in 1997 the lightning activity increases mainly in Southeast Asia, the Maritime Continent and India, i.e. the Asian chimney region. On the other hand, a global response in lightning is indicated by the anomalies in SR intensity in 2014 and 2015. SR‐based results are strengthened by comparison to independent lightning observations from the Optical Transient Detector and the World Wide Lightning Location Network, which also exhibit increased lightning activity in the transition months. The increased lightning is attributable to increased instability due to thermodynamic disequilibrium between the surface and the midtroposphere during the transition. The main conclusion is that variations in SR intensity may act as a precursor for the occurrence and magnitude of these extreme climate events, and in keeping with earlier findings, as a precursor to maxima in global surface air temperature.

Long-Term Observations of Schumann Resonances at Portishead (UK)

“…The observed inter-annual trend (solid red line in Figure 8a) decreases between June 2015 and June 2018, which corresponds to the SD extrema (maximum and minimum, respectively) recorded during the 5-year period, and subsequently becomes nearly constant. An exceptional increase of the SR intensity for the period 2015/2016 has been documented by other studies, that considered the SR modes average peak frequency and intensity measured at various observatories distributed globally [20,24,37]. In analogy with other SR amplitude observations taken at similar mid-high latitudes (i.e., Eskdalemuir [25]), the steady decline in the inter-annual SD is found to be in phase with the transition from the maximum to the minimum of the 11-year solar cycle (Figure 8c).…”

“…In the longer term, additional sources of variability include the north-south seasonal shift of global lightning, the SR response to lower ionosphere height changes linked to the solar activity, and redistribution of global thunderstorms on the ENSO time scale [18][19][20].…”

Solar Cycle-Modulated Deformation of the Earth–Ionosphere Cavity

“…Schumann resonances (SR) are excited primarily by lightning-radiated electromagnetic waves and the approximate number of 30-100 lightning strokes per second worldwide (Christian et al, 2003) maintains the resonance field quasi-continuously. It follows that SR are excellent indicators of lightning activity and distribution on global scales (see e.g., Williams et al, 2021). The possible connection between atmospheric electricity (including SR) and biological systems is another topic with substantial scientific interest (e.g., Elhalel et al, 2019;Fdez-Arroyabe et al, 2020;Price et al, 2021;Savoska et al, 2021;Sukhov et al, 2021).…”

Electric Field Measurements in the Antarctic Reveal Patterns Related to the El Niño—Southern Oscillation

“…• Electric field measurements in Antarctica show that strong El Niños and La Niñas consistently impact the atmospheric global circuit • For the super El Niño event of 2015/16, the anomalies in the global electric circuit are especially pronounced • Simulations show that the observed effect is due to changes in deep convection over the Pacific Ocean, Maritime Continent, and South America Williams et al, 2021;Yoshida et al, 2007), little attention has been given to its influence on quasi-stationary electric fields and currents in the atmosphere.…”