Extreme concentric gravity waves observed in the mesosphere and thermosphere regions over southern Brazil associated with fast-moving severe thunderstorms

Abstract

Abstract. Three groups of intense concentric gravity waves (CGWs) lasting over 10 h were observed by an airglow imager at the Southern Space Observatory (SSO) in São Martinho da Serra (29.44° S, 53.82° W) in southern Brazil on 17–18 September 2023. These CGW events were simultaneously captured by spaceborne instruments, including the Atmospheric Infrared Sounder (AIRS) aboard Aqua, the Visible Infrared Imaging Radiometer Suite (VIIRS) on board Suomi NPP, and the Sounding of the Atmosphere using Broadband Emission Radiometry (SABER) instrument operating on the Thermosphere-Ionosphere-Mesosphere Energetics and Dynamics (TIMED) satellite. The CGWs caused significant airglow radiation perturbations exceeding 24 %, and the distance of the wave centre movement exceeded 400 km. These CGW events were caused by fast-moving deep convection observed by the Geostationary Operational Environmental Satellite-16 (GOES-16). The weaker background wind field during the spring season transition provides the necessary conditions for CGWs to propagate from the lower atmosphere to the mesopause region. The 630 nm emission images were significantly contaminated by specific OH emission bands. The same CGW event was observed propagating from the OH airglow layer (∼ 87 km) to the thermospheric OI 630.0 nm airglow layer (∼ 250 km). The asymmetric propagation of CGWs in the thermosphere may be due to the vertical wavelength changes caused by the Doppler-shifting effect of the background wind field. This multilayer ground-based and satellite joint detection of CGWs offers an excellent perspective for examining the coupling of various atmospheric layers.