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Observation and modeling of gravity wave propagation through reflection and critical layers above Andes Lidar Observatory at Cerro Pachón, Chile
Author(s) -
Cao Bing,
Heale Christopher J.,
Guo Yafang,
Liu Alan Z.,
Snively Jonathan B.
Publication year - 2016
Publication title -
journal of geophysical research: atmospheres
Language(s) - English
Resource type - Journals
eISSN - 2169-8996
pISSN - 2169-897X
DOI - 10.1002/2016jd025173
Subject(s) - lidar , gravity wave , thermosphere , wavelength , geology , observatory , amplitude , refraction , airglow , wind speed , reflection (computer programming) , wave packet , gravitational wave , sky , mesosphere , depth sounding , geodesy , physics , atmospheric sciences , geophysics , optics , meteorology , remote sensing , astrophysics , ionosphere , stratosphere , quantum mechanics , programming language , oceanography , computer science
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, exceeding 10 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.