scholarly journals Airglow Measurements of Gravity Wave Propagation and Damping over Kolhapur (16.5°N, 74.2°E)

2014 ◽  
Vol 2014 ◽  
pp. 1-9 ◽  
Author(s):  
R. N. Ghodpage ◽  
A. Taori ◽  
P. T. Patil ◽  
S. Gurubaran ◽  
A. K. Sharma ◽  
...  
Keyword(s):  
Wave Propagation ◽  
Gravity Wave ◽  
Meridional Wind ◽  
Vertical Wavelength ◽  
Emission Layer ◽  
Positive Correlation ◽  
Intensity Measurements ◽  
Wind Shears ◽  
The Waves ◽  
Airglow Intensity

Simultaneous mesospheric OH and O  (1S) night airglow intensity measurements from Kolhapur (16.8°N, 74.2°E) reveal unambiguous gravity wave signatures with periods varying from 01 hr to 9 hr with upward propagation. The amplitudes growth of these waves is found to vary from 0.4 to 2.2 while propagating from the OH layer (~87 km) to the O (1S) layer (~97 km). We find that vertical wavelength of the observed waves increases with the wave period. The damping factors calculated for the observed waves show large variations and that most of these waves were damped while traveling from the OH emission layer to the O (1S) emission layer. The damping factors for the waves show a positive correlation at vertical wavelengths shorter than 40 km, while a negative correlation at higher vertical wavelengths. We note that the damping factors have stronger positive correlation with meridional wind shears compared to the zonal wind shears.

scholarly journals Gravity Wave Propagation from the Stratosphere into the Mesosphere Studied with Lidar, Meteor Radar, and TIMED/SABER

Atmosphere ◽  
2019 ◽  
Vol 10 (2) ◽  
pp. 81 ◽  
Author(s):  
Shaohua Gong ◽  
Guotao Yang ◽  
Jiyao Xu ◽  
Xiao Liu ◽  
Qinzeng Li
Keyword(s):  
Wave Propagation ◽  
Gravity Wave ◽  
Low Frequency ◽  
Phase Speed ◽  
Static Stability ◽  
Temperature Structure ◽  
Meteor Radar ◽  
Atmospheric Gravity Wave ◽  
Vertical Wavelength ◽  
Hodograph Method

A low-frequency inertial atmospheric gravity wave (AGW) event was studied with lidar (40.5° N, 116° E), meteor radar (40.3° N, 116.2° E), and TIMED/SABER at Beijing on 30 May 2012. Lidar measurements showed that the atmospheric temperature structure was persistently perturbed by AGWs propagating upward from the stratosphere into the mesosphere (35–86 km). The dominant contribution was from the waves with vertical wavelengths λ z = 8 − 10   km and wave periods T ob = 6.6 ± 0.7   h . Simultaneous observations from a meteor radar illustrated that MLT horizontal winds were perturbed by waves propagating upward with an azimuth angle of θ = 247 ° , and the vertical wavelength ( λ z = 10   km ) and intrinsic period ( T in = 7.4   h ) of the dominant waves were inferred with the hodograph method. TIMED/SABER measurements illustrated that the vertical temperature profiles were also perturbed by waves with dominant vertical wavelength λ z = 6 − 9   km . Observations from three different instruments were compared, and it was found that signatures in the temperature perturbations and horizontal winds were induced by identical AGWs. According to these coordinated observation results, the horizontal wavelength and intrinsic phase speed were inferred to be ~560 km and ~21 m/s, respectively. Analyses of the Brunt-Väisälä frequency and potential energy illustrated that this persistent wave propagation had good static stability.

Coupling between Gravity Waves and Tropical Convection at Mesoscales

2011 ◽  
Vol 68 (11) ◽  
pp. 2582-2598 ◽  
Author(s):  
Todd P. Lane ◽  
Fuqing Zhang
Keyword(s):  
Gravity Wave ◽  
Gravity Waves ◽  
Model Simulation ◽  
Wave Mode ◽  
Life Cycles ◽  
Cloud System ◽  
Vertical Wavelength ◽  
Convective Systems ◽  
The Waves ◽  
Horizontal Wavelength

Abstract An idealized cloud-system-resolving model simulation is used to examine the coupling between a tropical cloud population and the mesoscale gravity waves that it generates. Spectral analyses of the cloud and gravity wave fields identify a clear signal of coupling between the clouds and a deep tropospheric gravity wave mode with a vertical wavelength that matches the depth of the convection, which is about two-thirds of the tropospheric depth. This vertical wavelength and the period of the waves, defined by a characteristic convective time scale, means that the horizontal wavelength is constrained through the dispersion relation. Indeed, the wave–convection coupling manifests at the appropriate wavelength, with the emergence of quasi-regular cloud-system spacing of order 100 km. It is shown that cloud systems at this spacing achieve a quasi-resonant state, at least for a few convective life cycles. Such regular spacing is a key component of cloud organization and is likely a contributor to the processes controlling the upscale growth of convective systems. Other gravity wave processes are also elucidated, including their apparent role in the maintenance of convective systems by providing a mechanism for renewed convective activity and system longevity.

Influence of the upper atmosphere inhomogeneity on acoustic gravity wave propagation

2012 ◽  
Vol 18 (4(77)) ◽  
pp. 30-36 ◽  
Author(s):  
Y.I. Kryuchkov ◽  
◽  
O.K. Cheremnykh ◽  
A.K. Fedorenko ◽  
◽  
...  
Keyword(s):  
Wave Propagation ◽  
Gravity Wave ◽  
Upper Atmosphere ◽  
Acoustic Gravity Wave

scholarly journals Anomalous Anderson localization behavior in gain-loss balanced non-Hermitian systems

Nanophotonics ◽  
2020 ◽  
Vol 10 (1) ◽  
pp. 443-452
Author(s):  
Tianshu Jiang ◽  
Anan Fang ◽  
Zhao-Qing Zhang ◽  
Che Ting Chan
Keyword(s):  
Wave Propagation ◽  
Electromagnetic Waves ◽  
Anderson Localization ◽  
Random Media ◽  
Normal Incidence ◽  
Disordered Media ◽  
One Dimensional ◽  
Gain Loss ◽  
The Waves ◽  
Localization Behavior

AbstractIt has been shown recently that the backscattering of wave propagation in one-dimensional disordered media can be entirely suppressed for normal incidence by adding sample-specific gain and loss components to the medium. Here, we study the Anderson localization behaviors of electromagnetic waves in such gain-loss balanced random non-Hermitian systems when the waves are obliquely incident on the random media. We also study the case of normal incidence when the sample-specific gain-loss profile is slightly altered so that the Anderson localization occurs. Our results show that the Anderson localization in the non-Hermitian system behaves differently from random Hermitian systems in which the backscattering is suppressed.

scholarly journals Influence of the cloud-level neutral layer on the vertical propagation of topographically generated gravity waves on Venus

2019 ◽  
Vol 71 (1) ◽  
Author(s):  
Takeru Yamada ◽  
Takeshi Imamura ◽  
Tetsuya Fukuhara ◽  
Makoto Taguchi
Keyword(s):  
Layer Thickness ◽  
Gravity Wave ◽  
Local Time ◽  
Gravity Waves ◽  
Analytical Approach ◽  
Wave Activity ◽  
Neutral Layer ◽  
Low Latitudes ◽  
Vertical Propagation ◽  
The Waves

AbstractThe reason for stationary gravity waves at Venus’ cloud top to appear mostly at low latitudes in the afternoon is not understood. Since a neutral layer exists in the lower part of the cloud layer, the waves should be affected by the neutral layer before reaching the cloud top. To what extent gravity waves can propagate vertically through the neutral layer has been unclear. To examine the possibility that the variation of the neutral layer thickness is responsible for the dependence of the gravity wave activity on the latitude and the local time, we investigated the sensitivity of the vertical propagation of gravity waves on the neutral layer thickness using a numerical model. The results showed that stationary gravity waves with zonal wavelengths longer than 1000 km can propagate to the cloud-top level without notable attenuation in the neutral layer with realistic thicknesses of 5–15 km. This suggests that the observed latitudinal and local time variation of the gravity wave activity should be attributed to processes below the cloud. An analytical approach also showed that gravity waves with horizontal wavelengths shorter than tens of kilometers would be strongly attenuated in the neutral layer; such waves should originate in the altitude region above the neutral layer.

scholarly journals On the nature of short-period mesospheric gravity wave propagation over Halley, Antarctica

2012 ◽  
Vol 117 (D5) ◽  
pp. n/a-n/a ◽  
Author(s):  
K. Nielsen ◽  
M. J. Taylor ◽  
R. E. Hibbins ◽  
M. J. Jarvis ◽  
J. M. Russell
Keyword(s):  
Wave Propagation ◽  
Gravity Wave ◽  
Short Period

A Hemispheric and Seasonal Comparison of Tropospheric to Mesospheric Gravity‐Wave Propagation

2021 ◽  
Vol 126 (18) ◽  
Author(s):  
D. Alexandre ◽  
B. Thurairajah ◽  
S. L. England ◽  
C. Y. Cullens
Keyword(s):  
Wave Propagation ◽  
Gravity Wave

Acoustic gravity wave propagation past the antipode

1974 ◽  
Vol 55 (S1) ◽  
pp. S75-S75
Author(s):  
Wayne A. Kinney ◽  
Christopher Y. Kapper ◽  
Allan D. Pierce
Keyword(s):  
Wave Propagation ◽  
Gravity Wave ◽  
Acoustic Gravity Wave
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