Vertical Motion in Atmospheric Waves

1931 ◽  
Vol 17 (68) ◽  
pp. 257-258
Author(s):  
C.H. Ley
Keyword(s):  
Wave Motion ◽  
Vertical Motion ◽  
Distant Source ◽  
Low Velocity ◽  
Periodic Oscillations ◽  
Atmospheric Waves ◽  
Continuous Interaction ◽  
Air Motion

That vertical currents or components of air-motion having a velocity of several meters per second occasionally occur in the lowest tow kilometers of the atmosphere is an observed fact, but we are far as yet from compleate knowledge as to the conditions which produces such motionI suggest, however, that wave-motion proper, that is low-velocity, periodic oscillations of pressure or temperaturem whether transmitted from a distant source of disturbance, or occurring under the continuous interaction of two horizontal currents of air can be ruled from any list of hypothetical causes of important vertical motion.

Sensitivity of MCS Low-Frequency Gravity Waves to Microphysical Variations

2020 ◽  
Vol 77 (10) ◽  
pp. 3461-3477
Author(s):  
Rebecca D. Adams-Selin
Keyword(s):  
Numerical Simulations ◽  
Gravity Waves ◽  
Wave Motion ◽  
Low Frequency ◽  
Vertical Motion ◽  
Internal Variability ◽  
Initial Wave ◽  
Highly Sensitive ◽  
Heating Profiles ◽  
Melting Level

AbstractThe sensitivity of low-frequency gravity waves generated during the development and mature stages of an MCS to variations in the characteristics of the rimed ice parameterization were tested through idealized numerical simulations over a range of environment shears and instabilities. Latent cooling in the simulations with less dense, graupel-like rimed ice was more concentrated aloft near the melting level, while cooling in simulations with denser, hail-like rimed ice extended from the melting level to the surface. However, the cooling profiles still had significant internal variability across different environments and over each simulation’s duration. Initial wave production during the MCS developing stage was fairly similar in the hail and graupel simulations. During the mature stages, graupel simulations showed stronger perturbations in CAPE due to the cooling and associated wave vertical motion being farther aloft; hail simulations showed stronger perturbations in LFC due to cooling and wave vertical motion being concentrated at lower levels. The differences in the cooling profiles were not uniform enough to produce consistently different higher-order wave modes. However, the initiation of discrete cells ahead of the convective line was found to be highly sensitive to the nature of the prior destabilizing wave. Individual events of discrete propagation were suppressed in some of the graupel simulations due to the higher location of both peak cooling and vertical wave motion. Such results underscore the need to fully characterize MCS microphysical heating profiles and their low-frequency gravity waves to understand their structure and development.

DEEP CRUSTAL STRUCTURE UNDER THE PLAINS AND ROCKY MOUNTAINS

1966 ◽  
Vol 3 (7) ◽  
pp. 937-945 ◽  
Author(s):  
E. R. Kanasewich
Keyword(s):  
Rocky Mountains ◽  
Upper Mantle ◽  
Vertical Motion ◽  
Rocky Mountain ◽  
The United States ◽  
Continental Margins ◽  
Low Velocity ◽  
Mountain System ◽  
Deep Crustal Structure ◽  
Small Roots

The Airy hypothesis of isostatic compensation is very useful in accounting for structural differences between oceans and the continental margins. However, within the continents the compensation mechanism becomes more complicated. The thickness of the crust under much of the plains in the United States and Canada is between 40 and 55 kilometers. Determinations of crustal thickness under the Rocky Mountains gives results between 30 and 50 kilometers. Although local mountain ranges may have small roots, the Cordilleran region does not have a crustal root when compared to the plains. It follows that a modified form of Pratt's hypothesis of isostasy must be applied to continental regions. The density of the upper mantle is then different under the plains from what it is under the Rocky Mountains. In the plains it appears that there is a broad conformity of the Precambrian basement surface and the Mohorovicic discontinuity. Therefore the cause of epeirogenesis must lie within the upper mantle, possibly at the level of Gutenberg's low-velocity layer. The crustal studies in the plains and mountains indicate that more consideration should be given to gravitational gliding tectonics in the development of the Rocky Mountain system, since it is possible that there was substantial vertical motion of large crustal blocks.

STUDY OF THE EXISTENCE OF THE GLOBAL SOLUTION TO THE SYSTEM OF EQUATIONS OF THE VERTICAL MOTION OF THE AIR IN A CHIMNEY

2018 ◽  
pp. 583-594
Author(s):  
Sarra Ghomrani
Keyword(s):  
Global Solution ◽  
Existence And Uniqueness ◽  
Vertical Motion ◽  
System Of Equations ◽  
Air Motion

In this paper, we consider the system of equations that describes air motion in a chimney. By introducing a method based on the «second approximation», we prove a theorem on the existence and uniqueness of the global solution.

Motions of neutral hydrogen at high latitudes

1967 ◽  
Vol 31 ◽  
pp. 265-278 ◽  
Author(s):  
A. Blaauw ◽  
I. Fejes ◽  
C. R. Tolbert ◽  
A. N. M. Hulsbosch ◽  
E. Raimond
Keyword(s):  
Surface Density ◽  
Velocity Dispersion ◽  
Neutral Hydrogen ◽  
Hydrogen Gas ◽  
High Latitudes ◽  
Low Velocity

Earlier investigations have shown that there is a preponderance of negative velocities in the hydrogen gas at high latitudes, and that in certain areas very little low-velocity gas occurs. In the region 100° <l< 250°, + 40° <b< + 85°, there appears to be a disturbance, with velocities between - 30 and - 80 km/sec. This ‘streaming’ involves about 3000 (r/100)2solar masses (rin pc). In the same region there is a low surface density at low velocities (|V| < 30 km/sec). About 40% of the gas in the disturbance is in the form of separate concentrations superimposed on a relatively smooth background. The number of these concentrations as a function of velocity remains constant from - 30 to - 60 km/sec but drops rapidly at higher negative velocities. The velocity dispersion in the concentrations varies little about 6·2 km/sec. Concentrations at positive velocities are much less abundant.

Quasi-Periodic Oscillations in Dwarf Novae

1979 ◽  
Vol 46 ◽  
pp. 77-88
Author(s):  
Edward L. Robinson
Keyword(s):  
Binary Systems ◽  
Outer Edge ◽  
Light Curves ◽  
Close Binary ◽  
Bright Spot ◽  
Dwarf Novae ◽  
Periodic Oscillations ◽  
High Frequencies ◽  
Short Period ◽  
Typical Time

Three distinct kinds of rapid variations have been detected in the light curves of dwarf novae: rapid flickering, short period coherent oscillations, and quasi-periodic oscillations. The rapid flickering is seen in the light curves of most, if not all, dwarf novae, and is especially apparent during minimum light between eruptions. The flickering has a typical time scale of a few minutes or less and a typical amplitude of about .1 mag. The flickering is completely random and unpredictable; the power spectrum of flickering shows only a slow decrease from low to high frequencies. The observations of U Gem by Warner and Nather (1971) showed conclusively that most of the flickering is produced by variations in the luminosity of the bright spot near the outer edge of the accretion disk around the white dwarf in these close binary systems.

Atomic orientation effects in proton stopping at low velocity

1983 ◽  
Vol 41 ◽  
pp. 708-709
Author(s):  
Kin Lam
Keyword(s):  
Polycrystalline Material ◽  
Charged Particles ◽  
Target Material ◽  
Stopping Power ◽  
Low Velocity ◽  
Electronic Density ◽  
Interatomic Distances ◽  
Frame Work ◽  
Image Position ◽  
Atomic Orientation

The energy of moving ions in solid is dependent on the electronic density as well as the atomic structural properties of the target material. These factors contribute to the observable effects in polycrystalline material using the scanning ion microscope. Here we outline a method to investigate the dependence of low velocity proton stopping on interatomic distances and orientations.The interaction of charged particles with atoms in the frame work of the Fermi gas model was proposed by Lindhard. For a system of atoms, the electronic Lindhard stopping power can be generalized to the formwhere the stopping power function is defined as

PERIODIC OSCILLATIONS AND TURBULENCE OF HOT-CARRIER PLASMA AT 4.2 K IN n-GaAs

1981 ◽  
Vol 42 (C7) ◽  
pp. C7-51-C7-56
Author(s):  
K. Aoki ◽  
T. Kobayashi ◽  
K. Yamamoto
Keyword(s):  
Periodic Oscillations ◽  
Hot Carrier
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