Interaction among potential vorticity perturbations and propagating internal gravity waves in a horizontally sheared zonal flow is investigated. In the strong stratification limit, an initial vorticity perturbation weakly excites two propagating gravity waves while the density component of the potential vorticity perturbation is significantly amplified, potentially leading to convective collaps...

[1] The ‘‘Advanced Regional Prediction System’’ forecast model is extended up to the stratopause and over the entire hemisphere to simulate gravity waves during 24 January 2005. With a 15-km horizontal resolution, the simulation produces dominant gravity wave features near Eastern Greenland that are associated mainly with orographic forcing by the Greenland terrain. The simulated wave temperatu...

Parameterization schemes for the drag due to atmospheric gravity waves are discussed and compared in the context of a simple one-dimensional model of the quasi-biennial oscillation (QBO). A number of fundamental issues are examined in detail, with the goal of providing a better understanding of the mechanism by which gravity wave drag can produce an equatorial zonal wind oscillation. The gravit...

In order to study the filter effect of the background winds on the propagation of gravity waves, a threedimensional transfer function model is developed on the basis of the complex dispersion relation of internal gravity waves in a stratified dissipative atmosphere with background winds. Our model has successfully represented the main results of the ray tracing method, e.g. the trend of the gra...

Parameterization schemes for the drag due to atmospheric gravity waves are discussed and compared in the context of a simple one-dimensional model of the quasi-biennial oscillation (QBO). A number of fundamental issues are examined in detail, with the goal of providing a better understanding of the mechanism by which gravity wave drag can produce an equatorial zonal wind oscillation. The gravit...

Recent field observations and modelling of breaking surface gravity waves suggest that air-entraining breaking is not sufficiently dissipative of surface gravity waves to balance the dynamics of wind-wave growth and nonlinear interactions with dissipation for the shorter gravity waves of O(10) cm wavelength. Theories of parasitic capillary waves that form at the crest and forward face of shorte...

A nonlinear, compressible, spectral collocation code is employed to examine gravity wave breaking in two and three spatial dimensions. Twodimensional results exhibit a structure consistent with previous efforts and suggest wave instability occurs via convective rolls aligned normal to the gravity wave motion (uniform in the spanwise direction). Three-dimensionM results demonstrate, in contrast,...

[1] On the night of December 3rd, 2004 (UT day 338), we observed a significant acceleration of horizontal wind near 100 km between 0900 and 0915 UT accompanied by a temperature cooling at the same altitude and warming below it. The Lomb spectrum analysis of the raw dataset revealed that a gravity wavewith 1.5 hr periodwas significant between 0500 and 0900 UT, but blurred after 0900 UT, suggesti...

detection of subsurface structures by means of gravity method can be used to determine mass distribution and density contrast of rock units. this distribution could be detected by different geophysical methods, especially gravity method. however, gravity techniques have some drawbacks and can't be always successful in distinguishing subsurface structures. performance of the gravity technique co...