Gravity waves in the middle atmosphere observed by Rayleigh lidar 1. Case studies

Journal Article · Wed Mar 20 00:00:00 EST 1991 · Journal of Geophysical Research; (United States)

DOI:https://doi.org/10.1029/90JD02231· OSTI ID:5332617

Wilson, R; Chanin, M L; Hauchecorne, A ^[1]

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1. Service D'Aeronomie du CNRS, Verrieres le Buisson (France)

Density and temperature mesoscale fluctuations as observed in the stratosphere and mesosphere by means of two Rayleigh lidars with high resolution in time (15 min) and space (300 m), have been analyzed in some particular cases corresponding to different seasonal conditions. These case studies are characteristic of recurrently observed patterns and thus provide a description of the mesoscale fluctuation field in the middle atmosphere. The spatial, temporal, and spectral characteristics of the fluctuations are described and discussed in the framework of the gravity wave interpretation. Dominant wave modes with large period and large vertical wavelength (inertia-gravity waves) are frequently observed in the stratosphere and lower mesosphere. These low-frequency modes are not generally observed above 50- to 55-km altitude, suggesting a strong damping of such waves in the mesosphere. The vertical growth of potential energy density indicates that the wave motions are generally not conservative in the middle atmosphere. The gravity waves amplitude appears too small to produce convective instabilities in the stratosphere. On the contrary, the amplitude of the fluctuations is close to the convective saturation limit deduced from the linear theory for wavelengths up to 3-5 km in the lower mesosphere, and up to 6-8 km above 60 km altitude. Furthermore, convectively instable layers, which can persist for periods longer than one hour, have been frequently observed in the mesosphere.

• OSTI ID: 5332617
• Journal Information: Journal of Geophysical Research; (United States), Vol. 96:D3; ISSN 0148-0227
• Country of Publication: United States
• Language: English

Related Subjects

54 ENVIRONMENTAL SCIENCES
MESOSPHERE
GRAVITY WAVES
STRATOSPHERE
ALTITUDE
ANGULAR MOMENTUM
DENSITY
FLUCTUATIONS
OPTICAL RADAR
SEASONAL VARIATIONS
SPATIAL DISTRIBUTION
SPECTRAL FUNCTIONS
TEMPERATURE DISTRIBUTION
TIME DEPENDENCE
TURBULENCE
WAVELENGTHS
DISTRIBUTION
EARTH ATMOSPHERE
FUNCTIONS
MEASURING INSTRUMENTS
PHYSICAL PROPERTIES
RADAR
RANGE FINDERS
VARIATIONS
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