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A case study of mesospheric gravity wave momentum flux and dynamical instability using the Arecibo dual beam incoherent scatter radar
Author(s) -
Zhou Qihou,
Morton Y. T.
Publication year - 2006
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2005gl025608
Subject(s) - physics , gravity wave , gravitational wave , instability , incoherent scatter , flux (metallurgy) , geophysics , mesosphere , daytime , momentum (technical analysis) , ionosphere , atmospheric sciences , astrophysics , mechanics , stratosphere , materials science , metallurgy , finance , economics
We report the first observation of gravity wave momentum flux in the mesosphere using the dual‐beam Arecibo incoherent scatter radar (ISR). Quasi‐monochromatic waves were observed throughout the daytime of July 28, 2001 in the altitude range of 65–85 km. The largest wave speed was about 100 m/s and the dominant period was about 15 min. Instability, as indicated by the Richardson number, occurred at several altitudes, most dramatically at 77 and 81 kilometers. The zonal momentum flux is found to change sign at altitudes where dynamical instability occurs. No significant gravity waves were observed in the region having an eastward background wind, while they were ubiquitous when the background wind was westward.