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Power spectrum of a gravity wave propagating in a shearing background wind
Author(s) -
Pulido Manuel,
Caranti Giorgio
Publication year - 2000
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 - 10.1029/1999gl010819
Subject(s) - amplitude , wavenumber , physics , spectral slope , spectral density , shearing (physics) , gravity wave , leakage (economics) , gravitational wave , mechanics , geology , wave propagation , optics , spectral line , astrophysics , mathematics , statistics , macroeconomics , astronomy , economics , thermodynamics
We re‐analyze the effect on the spectral tail of a gravity wave propagating in a shearing background. The contribution to the spectrum of horizontal wind perturbations for low vertical wavenumbers comes from the Doppler shifting with a −1 slope and for high wavenumbers from the leakage effect with slopes ranging between −4 to −2. If leakage is not present, it becomes necessary to consider the termination of the wave in order to account for the spectral tail. We show that the decreasing of the wave amplitude when the overturning starts, leads to a spectral slope of −3, and an amplitude proportional to N² (the square of the Brünt Väisälä frequency).