Intense concentric gravity waves from the stratosphere to the thermosphere and a massive red sprite outbreak triggered by severe thunderstorms South of the Himalayas

Abstract. Severe thunderstorms drive vertical coupling through electrical processes associated with transient luminous events (TLEs) and dynamical processes associated with atmospheric gravity waves (AGWs). On 19 May 2022, an exceptionally intense thunderstorm outbreak occurred over the northern Bay of Bengal–Himalayan foothill region. The storm system produced more than 100 red sprites, 16 secondary gigantic jets, and at least four ghosts, accompanied by visible concentric airglow ripples. This event represented the first large-scale detection of a massive red sprite outbreak in China. From a dynamical perspective, concentric gravity waves (CGWs) were observed from the stratosphere to the thermosphere using coordinated satellite and ground-based airglow observations. AIRS measurements revealed concentric wave structures in the stratosphere above the convective source region, while ground-based airglow imagers detected CGWs in the OH, OI 557.7 nm, and OI 630.0 nm emission layers. CGWs in the mesosphere and lower thermosphere (MLT) propagated northeastward for more than 3000 km, suggesting propagation within favorable MLT ducting structures. In contrast, thermospheric CGWs observed in the OI 630.0 nm emission exhibited horizontal phase speeds of 260–280 m s⁻¹. Reverse ray-tracing analysis indicates a preferred source altitude near 150 km, suggesting that these waves were likely secondary gravity waves generated by the dissipation and breaking of upward-propagating primary gravity waves. Their asymmetric occurrence is likely attributable to Doppler-induced dissipation associated with thermospheric background winds. These observations provide a rare example of simultaneous electrical and dynamical coupling from the troposphere to the thermosphere during an extreme convective event.