Simultaneous observations of convective gravity waves from a ground-based airglow imager and the AIRS satellite experiment

We report the first joint observations of convectively generated gravity waves (GWs) using an OH airglow imager in Colorado and the Atmospheric Infrared Sounder (AIRS) onboard the Aqua satellite. Convective GWs, appearing as concentric rings, are observed over the western Great Plain regions of North America in the evening of 3 June 2008 in the airglow images. Inspecting both weather radars and AIRS radiances at 8.1 mm, strong convective clouds are found near the center of the concentric rings. The AIRS data at 4.3 mm show semicircular GWs with horizontal wavelengths of 60–80 km at 0900 UT, whereas the airglow imager observed circular GWs with horizontal wavelengths of ~44 km and airglow emission perturbation of ~6% at the same geographic location at 0910 UT. Large-scale GWs (horizontal wavelengths greater than 100 km) emanating northwestward can be seen in both AIRS data and airglow images at different times. The imager observed small-scale ripples associated with unstable concentric GWs in the mesopause in the early evening. Given that the brightness temperature perturbation of the GWs in the AIRS data is about 0.16 K and assuming that the GWs propagate without dissipation from the stratosphere to the upper mesosphere, the expected airglow emission perturbation caused by the GWs would be 4%–17%. Ray tracing simulations are performed to demonstrate that the GWs seen in AIRS and in the imager were likely excited by the same convective system.