A complex gravity wave event was observed from 04:30 to 08:10 UTC on 16 January 2015 by a narrow-band sodium lidar and an all-sky airglow imager located at Andes Lidar Observatory (ALO) in Cerro Pachón (30.25∘S, 70.73∘W), Chile. The gravity wave packet had a period of 18–35 min and a horizontal wavelength of about 40–50 km. Strong enhancements of the vertical wind perturbation, exceeding10 m s−1, were found at ∼90 km and ∼103 km, consistent with nearly evanescent wave behavior near a reﬂection layer. A reduction in vertical wavelength was found as the phase speed approached the background wind speed near ∼93 km. A distinct three-layered structure was observed in the lidar data due to refraction of the wave packet. A fully nonlinear model was used to simulate this event, which successfully reproduced the amplitudes and layered structure seen in observations. The model results provide dynamical insight, suggesting that a double reﬂection occurring at two separate heights caused the large vertical wind amplitudes, while the three-layered structure in the temperature perturbation was a result of relatively stable regions at those altitudes. The event provides a clear perspective on the ﬁltering processes to which short-period, small-scale gravity waves are subject in mesosphere and lower thermosphere.
Journal of Geophysical Research: Atmospheres
American Geophysical Union
Scholarly Commons Citation
Cao, B., Heale, C. J., Guo, Y., Liu, A. Z., & Snively, J. B. (2016). Observation and Modeling of Gravity Wave Propagation through Reflection and Critical Layers above Andes Lidar Observatory at Cerro Pachón, Chile. Journal of Geophysical Research: Atmospheres, 121(21). https://doi.org/10.1002/2016JD025173