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Atmospheric gravity waves (AGWs) are among the important energy and momentum transfer mechanisms from the troposphere to the middle and upper atmosphere. Despite their understood importance in governing the structure and dynamics of these regions, mesospheric AGWs remain poorly measured globally, and largely unconstrained in numerical models. Since late 2011, the Suomi National Polar-orbiting Partnership (NPP) Visible/Infrared Imaging Radiometer Suite (VIIRS) day–night band (DNB) has observed global AGWs near the mesopause by virtue of its sensitivity to weak emissions of the OH* Meinel bands. The wave features, detectable at 0.75 km spatial resolution across its 3000 km imagery swath, are often confused by the upwelling emission of city lights and clouds reflecting downwelling nightglow. The Ionosphere, Mesosphere, upper Atmosphere and Plasmasphere (IMAP)/ Visible and near-Infrared Spectral Imager (VISI) O2 band, an independent measure of the AGW structures in nightglow based on the International Space Station (ISS) during 2012–2015, contains much less noise from the lower atmosphere. However, VISI offers much coarser resolution of 14–16 km and a narrower swath width of 600 km. Here, we present preliminary results of comparisons between VIIRS/DNB and VISI observations of AGWs, focusing on several concentric AGW events excited by the thunderstorms over Eastern Asia in August 2013. The comparisons point toward suggested improvements for future spaceborne airglow sensor designs targeting AGWs. 

Abstract A mountain wave with a significant brightness temperature amplitude and ~500 km horizontal wavelength was observed over the Andes on 24–25 July 2017 in Atmospheric Infrared Sounder (AIRS)/Aqua satellite data. In the Modern‐Era Retrospective Analysis for Research and Applications, version 2 (MERRA‐2), reanalysis data, the intense eastward wind flowed over the Andes. Visible/Infrared Imaging Radiometer Suite (VIIRS)/Suomi‐NPP (National Polar‐orbiting Partnership) did not detect the mountain waves; however, it observed concentric ring‐like waves in the nightglow emissions at ~87 km with ~100 km wavelengths on the same night over and leeward of the Southern Andes. A ray tracing analysis showed that the mountain waves propagated to the east of the Andes, where concentric ring‐like waves appeared above a region of mountain wave breaking. Therefore, the concentric ring‐like waves were likely secondary waves generated by momentum deposition that accompanied mountain wave breaking. These results provide the first direct evidence for secondary gravity waves generated by momentum deposition.