Abstract: Previous studies have revealed a number of unstable modes in addition to the Kelvin-Helmholtz instability associated with a velocity shear in the presence of a rigid lower boundary. These additional modes occupy regions ...

Abstract: This paper addresses the efficiency and characteristics of two mechanisms that have been proposed to account for the excitation of radiating gravity waves by Kelvin-Helmholtz (KH) instabilities at a free shear layer in a ...

Abstract: In this study we examine some of the effects of wave-wave interactions and convective adjustment on the propagation of gravity waves in the middle atmosphere. For both a nearly monochromatic wave and a super-position of ...

Abstract: Unstable Velocity shears are a Common source of vertically propagating gravity waves in the atmosphere. However, the growth rates of unstable modes predicted by linear theory cannot always amount for their observed importance. ...

Abstract: A nonlinear numerical model of the gravity wave-critical level interaction is developed in this paper. This model is used to examine and compare the effects of viscosity, time-dependence and nonlinear interactions on the ...

Abstract: The gravity wave-critical level interaction is found to excite both radiating waves and Kelvin-Helmholtz instabilities through nonlinear interactions near the critical level. Radiating waves are forced directly by perturbations ...

Abstract: The effect of a vertically propagating, internal gravity wave on the vertical flux of potential temperature (heat) is considered by averaging the local heat flux vector over a potential temperature surface. This approach ...

Abstract: We present a stability analysis of the environment due to a large-amplitude inertio?gravity wave. Our purpose is to examine the conditions under which the Kelvin-Helmholtz (KH) instability may be an effective wave saturation ...

Abstract: Linear theory is used to examine the influence of a mean shear on the dynamical instability of a large-amplitude inertio-gravity wave (IGW). The strength and orientation of the mean shear and the frequency of the IGW are ...

Abstract: Observations of the motion field near the summer mesopause using the Poker Flat MST radar in a symmetric six-beam configuration during 8 days of July 1986 were used to examine the mean structure, the wave variances, and ...