VHF radar observation of gravity wave critical layers in the mid-latitude summer mesopause region

Journal Article · Mon Apr 01 04:00:00 EST 1991 · Geophysical Research Letters (American Geophysical Union); (United States)

OSTI ID:5407332

Yi, Fan; Klostermeyer, J; Ruester, R ^[1]

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1. Max-Planck Inst. fur Aeronomie, Katlenburg-Lindau (West Germany)

Observations with the SOUSY VHF Radar in the mesopause region during summer 1989 show layers of strong echo intensity and wind speeds increasing with height. Occasionally, quasi-monochromatic internal gravity waves occur in the bottom side of the echo layer and vanish in the height interval around the echo intensity maximum which tends to increase with increasing wave amplitude. The data analysis can be performed using a Boussinesq and a WKB approximation. It shows that the horizontal phase trace velocity of the observed gravity waves is equal to the background wind velocity at the height of the echo intensity maximum. The observations thus represent nonlinear gravity wave-critical level encounters producing strong turbulence in the neutral gas. But the estimated energy dissipation rates are too small to produce neutral gas turbulence at scales equal to half the radar wavelength yielding an additional indication for a yet unidentified mechanism generating small-scale structures in the electron gas.

• OSTI ID: 5407332
• Journal Information: Geophysical Research Letters (American Geophysical Union); (United States), Journal Name: Geophysical Research Letters (American Geophysical Union); (United States) Vol. 18:4; ISSN 0094-8276; ISSN GPRLA
• Country of Publication: United States
• Language: English

Related Subjects

54 ENVIRONMENTAL SCIENCES
540110*
DATA ANALYSIS
DEVELOPED COUNTRIES
EARTH ATMOSPHERE
ENERGY LOSSES
EUROPE
FEDERAL REPUBLIC OF GERMANY
GEOGRAPHICAL VARIATIONS
GRAVITY WAVES
LATITUDE EFFECT
LOSSES
MEASURING INSTRUMENTS
MESOSPHERE
RADAR
RANGE FINDERS
STRATIFICATION
TURBULENCE
VARIATIONS
WAVELENGTHS
WIND