Kelvin-Helmholtz billows and their effects on mean state during gravity wave propagation

Liu, X.; Xu, Jiyao; Gao, Hong; Chen, G.

doi:10.5194/angeo-27-2789-2009

Cited by 15 publications

(8 citation statements)

References 33 publications

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“…The Rayleigh friction α(z) is adapted from Xu et al (2003), and is utilized to reduce or eliminate spurious reflection from the lower and upper boundaries. Note that the above equations are slightly different from those used in Liu et al (2008Liu et al ( , 2009) with respect to the diffusion terms in Eqs. (2) and (3).…”

Section: Governing Equations and Calculationsmentioning

confidence: 99%

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Numerical modeling study of the momentum deposition of small amplitude gravity waves in the thermosphere

Liu

Yue

et al. 2013

Ann. Geophys.

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Abstract. We study the momentum deposition in the thermosphere from the dissipation of small amplitude gravity waves (GWs) within a wave packet using a fully nonlinear two-dimensional compressible numerical model. The model solves the nonlinear propagation and dissipation of a GW packet from the stratosphere into the thermosphere with realistic molecular viscosity and thermal diffusivity for various Prandtl numbers. The numerical simulations are performed for GW packets with initial vertical wavelengths (λ z ) ranging from 5 to 50 km. We show that λ z decreases in time as a GW packet dissipates in the thermosphere, in agreement with the ray trace results of Vadas and Fritts (2005) (VF05). We also find good agreement for the peak height of the momentum flux (z diss ) between our simulations and VF05 for GWs with initial λ z ≤ 2πH in an isothermal, windless background, where H is the density scale height. We also confirm that z diss increases with increasing Prandtl number. We include eddy diffusion in the model, and find that the momentum deposition occurs at lower altitudes and has two separate peaks for GW packets with small initial λ z . We also simulate GW packets in a non-isothermal atmosphere. The net λ z profile is a competition between its decrease from viscosity and its increase from the increasing background temperature. We find that the wave packet disperses more in the non-isothermal atmosphere, and causes changes to the momentum flux and λ z spectra at both early and late times for GW packets with initial λ z ≥ 10 km. These effects are caused by the increase in T in the thermosphere, and the decrease in T near the mesopause.

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Section: Governing Equations and Calculationsmentioning

confidence: 99%

“…The method used to solve Eqs. (1)- (4) is the same as that in Liu et al (2008Liu et al ( , 2009), and will not be repeated here.…”

Section: Governing Equations and Calculationsmentioning

confidence: 99%

Numerical modeling study of the momentum deposition of small amplitude gravity waves in the thermosphere

Liu

Yue

et al. 2013

Ann. Geophys.

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“…One of the most important problems of dynamic meteorology is the generation, propagation, and decay of internal gravity waves in the atmosphere, because [4][5][6]) or the numeri cal modeling studies of mesoscale and large scale wave processes [7][8][9][10]. Far less attention is paid to observa tions of the waves in the atmosphere, their climatol ogy, and measurements of their parameters.…”

Section: Introductionmentioning

confidence: 99%

Internal gravity-shear waves in the atmospheric boundary layer from acoustic remote sensing data

Lyulyukin

Kallistratova

Kouznetsov

et al. 2015

Izv. Atmos. Ocean. Phys.

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The year round continuous remote sounding of the atmospheric boundary layer (ABL) by means of the Doppler acoustic radar (sodar) LATAN 3 has been performed at the Zvenigorod Scientific Station of the Obukhov Institute of Atmospheric Physics, Russian Academy of Sciences, since 2008. A visual analysis of sodar echograms for four years revealed a large number of wavelike patterns in the intensity field of a scat tered sound signal. Similar patterns were occasionally identified before in sodar, radar, and lidar sounding data. These patterns in the form of quasi periodic inclined stripes, or cat's eyes, arise under stable stratifica tion and significant vertical wind shears and result from the loss of the dynamic stability of the flow. In the foreign literature, these patterns, which we call internal gravity shear waves, are often associated with Kelvin-Helmholtz waves. In the present paper, sodar echograms are classified according to the presence or absence of wavelike patterns, and a statistical analysis of the frequency of their occurrence by the year and season was performed. A relationship between the occurrence of the patterns and wind shear and between the wave length and amplitude was investigated. The criteria for the identification of gravity shear waves, mete orological conditions of their excitation, and issues related to their observations were discussed.

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“…Figure 1 shows that turbulence is generated in the second half of the data through the third‐order structure function; this phenomenon is verified through the evolution of spectral structure with time. Liu et al (2009) used numerical simulation to investigate the effect of KH waves on the average state of the atmosphere during the propagation of gravity waves and found that before the KH waves are fully developed, the increased amplitude of unsaturated gravity waves will increase the spectral slope. When the KH wave is fully developed, the energy is transmitted from the large scale to the small scale, and the spectral slope decreases.…”

Section: Resultsmentioning

confidence: 99%

The Interaction Between the Turbulence and Gravity Wave Observed in the Middle Stratosphere Based on the Round‐Trip Intelligent Sounding System

Sheng

2020

Geophysical Research Letters

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Based on the round‐trip intelligent sounding system, the structure function and spectrum analysis method were carried out to analyze the scale interactions between the small‐scale gravity wave and turbulence in the middle stratosphere. The result showed that the generation of turbulence was closely related to the Kelvin‐Helmholtz (KH) billows. An upscale energy cascade occurred on the spatial scale of KH billows, while a downscale energy cascade occurred on a larger spatial scale (gravity wave scale), which resulted in the breaking of the gravity wave and generation of turbulence. From the multilevel signal measurement, the obvious interactions between turbulence and gravity can be found. The two‐dimensional turbulence that the inverse energy cascade in 2‐D exists simultaneously with a direct enstrophy cascade to the small scales was found, which is considered to be the first‐hand observation result of relevant height.

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Kelvin-Helmholtz billows and their effects on mean state during gravity wave propagation

Cited by 15 publications

References 33 publications

Numerical modeling study of the momentum deposition of small amplitude gravity waves in the thermosphere

Numerical modeling study of the momentum deposition of small amplitude gravity waves in the thermosphere

Internal gravity-shear waves in the atmospheric boundary layer from acoustic remote sensing data

The Interaction Between the Turbulence and Gravity Wave Observed in the Middle Stratosphere Based on the Round‐Trip Intelligent Sounding System

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