The Enhancement of Neutral Metal Na Layer Above Thunderstorms

Abstract

Atomic sodium (Na) is one of the major meteoric species existing as layers of atoms in the mesosphere/lower thermosphere (MLT) at altitudes of 80–105 km and atomic ions at higher altitudes. As the boundary between neutral atmosphere and ionosphere, the MLT region is of particular interest because it is influenced by the mesoscale convective weather and thunderstorms from below and exposed to solar photons from above. There has been great interest on the atmosphere‐ionosphere coupling, and numerous studies have been reported on the connection between thunderstorms and the ionosphere. However, the influence of thunderstorms on metallic species, which would significantly enhance our understanding of how Earth's atmosphere interacts with its ionosphere and studying the chemistry and physics of the MLT region, has rarely been studied. Here we present observational results on a statistical basis showing evidence that thunderstorm activities can affect the metal layer, by identifying a statistically significant enhancement of the neutral metal Na layer above thunderstorms at Haikou, China (20.0°N, 110.3°E). The thunderstorm‐generated gravity waves and electric field effects could be the mechanisms responsible for the lightning‐associated enhancement of Na layer.

The intensification of metallic layered phenomena above thunderstorms through the modulation of atmospheric tides

“…The lag time ranges from several hours to more than 30 hours 15,26,29 . Recent work reported a novel observation of the meteoric metals in the mesosphere, and atomic Na layer, that is significantly intensified ~19 h after lightning 30 . Nearly all these studies of lightning-induced effects on the metallic layered phenomena were statistical results obtained using the SEA method, and it is difficult to explain such time lags by GWs or electrodynamic effects induced by lightning alone.…”

Observations of Red Sprites Above Hurricane Matthew

“…There is increasing interest to understand the impact of thunderstorms and associated lightning activity on the lower ionosphere (Davis & Johnson, 2005;Shao et al, 2013;Yu et al, 2017). Major impacts include lightning-induced transient luminous events in the mesosphere, such as red sprites (Sentman et al, 1995), gigantic jets (Liu, Spiva, et al, 2015;Pasko et al, 1997), and elves (Taranenko et al, 1993).…”

The intensification of metallic layered phenomena above thunderstorms through the modulation of atmospheric tides

“…It has been previously revealed that there is a relationship between neutral metal Na layer and thunderstorms, that is an enhancement of neutral Na layer in response to lightning (Yu et al, 2017). The lightning-induced statistically enhanced Na layer events distributed on 28 thunderstorm nights are further analyzed here to study the possible mechanism, on the basis of the Na lidar data and ionospheric data from two digisondes.…”

“…The time lag ranges from several hours to more than 30 hours (Davis and Johnson, 2005;Johnson and Davis, 2006;Yu et al, 2015). The recent work reported a novel observation of the meteoric metals in the mesosphere, atomic Na layer that is significantly intensified ∼19 h after lightning using SEA method (Yu et al, 2017). Nearly all these studies of lightning-induced effects on the metallic layered phenomena were statistical results from the SEA method, and it is difficult to explain by the GWs or electrodynamic effects induced by lightning.…”

“…The lightning-induced statistically enhanced Na layer events distributed on 28 thunderstorm nights are further analyzed here to study the possible mechanism, on the basis of the Na lidar data and ionospheric data from two digisondes. Figure 1a shows the residual of neutral metal Na median density for 150 hours either side of the lightning trigger events, after removing the diurnal trend (the difference of median response of Na density and median response of Gaussian random Na density after lightning trigger times in Yu et al (2017)). The 99.9 % significant level is contoured as the solid white lines (i.e.…”