How are the gravity waves triggered by typhoon propagate from the troposphere to upper atmosphere?

Abstract. Gravity waves (GWs) strongly affect atmospheric dynamics, and photochemistry, as well as the coupling between the troposphere, stratosphere, mesosphere, and thermosphere. Also, GWs generated by strong disturbances in the troposphere (such as thunderstorms, typhoons, etc.) can affect the atmosphere of the Earth ranging from the troposphere to the thermosphere. However, the fundamental process of GW propagation from the troposphere to the thermosphere is poorly understood because it is challenging to constrain this process by observations. Moreover, GWs tend to dissipate rapidly in the thermosphere because the molecular diffusion increases exponentially. In this study, a double-layer airglow network is used to capture the concentric gravity waves (CGWs) over China, which were excited by the Super Typhoon Chaba (2016). We used the ERA-5 reanalysis data and Multi-functional Transport Satellite-1R observations and quantitatively described the physical mechanism of typhoon-generated CGWs propagating throughout the stratosphere, mesosphere, and thermosphere. We found that the CGWs in the mesopause region were generated directly by the typhoon in the troposphere. However, the backward ray tracing analysis revealed that CGWs in the thermosphere originated from the secondary waves generated by the dissipation of the CGW in the mesopause region, thereby resembling the relay in the context.