scholarly journals Low-frequency inertia-gravity waves in the stratosphere revealed by three-week continuous observation with the MU radar

1997 ◽  
Vol 24 (14) ◽  
pp. 1739-1742 ◽  
Author(s):  
Kaoru Sato ◽  
Donal J. O'Sullivan ◽  
Timothy J. Dunkerton
Keyword(s):  
Gravity Waves ◽  
Low Frequency ◽  
Continuous Observation ◽  
Mu Radar ◽  
Inertia Gravity Waves

On the effects of frontogenetic strain on symmetric instability and inertia–gravity waves

2012 ◽  
Vol 711 ◽  
pp. 620-640 ◽  
Author(s):  
Leif N. Thomas
Keyword(s):  
Gravity Waves ◽  
Richardson Number ◽  
Low Frequency ◽  
Deformation Field ◽  
Vertical Shear ◽  
Geostrophic Flow ◽  
Ageostrophic Circulation ◽  
The Waves ◽  
Symmetric Instability ◽  
Inertia Gravity Waves

AbstractThe dynamics of symmetric instability and two-dimensional inertia–gravity waves in a baroclinic geostrophic flow undergoing frontogenesis is analysed. A frontogenetic strain associated with a balanced deformation field drives an ageostrophic circulation and temporal variations in the basic state that significantly affect the properties of perturbations to the background flow. For stable stratification, perturbations to the basic state result in symmetric instability or inertia–gravity waves, depending on the sign of the Ertel potential vorticity and the magnitude of the Richardson number of the geostrophic flow. The kinetic energy (KE) of both types of motion is suppressed by frontogenetic strain due to the vertical shear in the ageostrophic circulation. This is because the perturbation streamlines tilt with the ageostrophic shear causing the disturbances to lose KE via shear production. The effect can completely dampen symmetric instability for sufficiently strong strain even though the source of KE for the instability (the vertical shear in the geostrophic flow) increases with time. Inertia–gravity waves in a baroclinic flow undergoing frontogenesis simultaneously lose KE and extract KE from the deformation field as they decay. This is because the horizontal velocity of the waves becomes rectilinear, resulting in a Reynolds stress that draws energy from the balanced flow. The process is most effective for waves of low frequency and for a geostrophic flow with low Richardson number. However, even in a background flow that is initially strongly stratified, frontogenesis leads to an exponentially fast reduction in the Richardson number, facilitating a rapid energy extraction by the waves. The KE transferred from the deformation field is ultimately lost to the unbalanced ageostrophic circulation through shear production, hence the inertia–gravity waves play a catalytic role in loss of balance. Given the large amount of KE in low-frequency inertia–gravity waves and the ubiquitous combination of strain and baroclinic geostrophic currents in the ocean, it is estimated that this mechanism could play a significant role in the removal of KE from both the internal wave and mesoscale eddy fields.

Semi-Lagrangian exponential time-integration method for the shallow water equations on the cubed sphere grid

2020 ◽  
Vol 35 (6) ◽  
pp. 355-366
Author(s):  
Vladimir V. Shashkin ◽  
Gordey S. Goyman
Keyword(s):  
Shallow Water ◽  
Gravity Waves ◽  
Shallow Water Equations ◽  
Time Integration ◽  
Standard Test ◽  
Integration Scheme ◽  
Test Problems ◽  
Cubed Sphere ◽  
Lagrangian Scheme ◽  
Inertia Gravity Waves

AbstractThis paper proposes the combination of matrix exponential method with the semi-Lagrangian approach for the time integration of shallow water equations on the sphere. The second order accuracy of the developed scheme is shown. Exponential semi-Lagrangian scheme in the combination with spatial approximation on the cubed-sphere grid is verified using the standard test problems for shallow water models. The developed scheme is as good as the conventional semi-implicit semi-Lagrangian scheme in accuracy of slowly varying flow component reproduction and significantly better in the reproduction of the fast inertia-gravity waves. The accuracy of inertia-gravity waves reproduction is close to that of the explicit time-integration scheme. The computational efficiency of the proposed exponential semi-Lagrangian scheme is somewhat lower than the efficiency of semi-implicit semi-Lagrangian scheme, but significantly higher than the efficiency of explicit, semi-implicit, and exponential Eulerian schemes.

scholarly journals A study of the low-frequency inertio-gravity waves observed during the Pyrénées Experiment

1998 ◽  
Vol 103 (D2) ◽  
pp. 1747-1758 ◽  
Author(s):  
C. M. Scavuzzo ◽  
M. A. Lamfri ◽  
H. Teitelbaum ◽  
F. Lott
Keyword(s):  
Gravity Waves ◽  
Low Frequency

Spontaneous-adjustment emission of inertia-gravity waves by unsteady vortical motion in the hurricane core

2010 ◽  
Vol 136 (647) ◽  
pp. 537-548 ◽  
Author(s):  
E. A. Hendricks ◽  
W. H. Schubert ◽  
S. R. Fulton ◽  
B. D. McNoldy
Keyword(s):  
Gravity Waves ◽  
Vortical Motion ◽  
Inertia Gravity Waves
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