Convective cells of internal gravity waves in the earth's atmosphere with finite temperature gradient

Onishchenko, O. G.; Pokhotelov, O. A.; Fedun, V.

doi:10.5194/angeo-31-459-2013

Cited by 16 publications

(9 citation statements)

References 19 publications

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“…Propagating up into the middle/upper atmosphere, the gravity wave amplitude increases exponentially to compensate the energy loss due to decrease in atmospheric density with height. In recent times there has been a renewed interest to study these gravity waves to understand the impacts not only on governing mesospheric and upper atmospheric processes but also the tropospheric weather and climate system because of their ubiquitous nature (Onishchenko et al, 2013). In the present study the results of the signatures of small period (10-40 min) gravity waves in the troposphere and their subsequent propagation to the mesosphere are clearly demonstrated from the MST radar observations over the tropical Indian station.…”

Section: Discussionmentioning

confidence: 63%

Propagation of short period (10-40min) atmospheric gravity waves from troposphere to mesosphere over Gadanki, India

Chakravarty

Nagaraja

2015

Journal of Atmospheric and Solar-Terrestrial Physics

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a b s t r a c tThe Indian MST radar at Gadanki (13.5°N, 79.2°E) has been utilised to conduct a detailed study of the close coupling between the troposphere and the mesosphere through the vertically propagating atmospheric gravity waves. For this purpose two cases from a special campaign dedicated to the simultaneous measurement of the fluctuations in the UTLS (Upper Troposphere and Lower Stratosphere) and in the mesosphere during 2001 and one case from a follow up observation in 2002 have been investigated. By using both the FFT and wavelet techniques, the near simultaneous tropospheric and mesospheric data of radar return signal strengths and tropospheric wind fields are analysed. The signatures of relatively high frequency gravity waves with periods between $ 10 and 40 min have been clearly traced as propagating waves from the tropospheric turbulent layer heights ( $ 8-18 km) to the lower mesospheric heights (65-80 km). Significant peak correlation coefficients of 0.56 and 0.45 have been found between the SNR time series of pairs of troposphere and mesosphere levels indicating the propagation of high speed gravity waves. The time series of wavelet spectra determined for the tropospheric SNR/zonal winds and the mesospheric SNR show that the detectability of the gravity waves increases at mesospheric heights. It is shown that the continuous SNR values received from the mesosphere can be used as an effective parameter for studies featuring mesospheric wave dynamics. Based on the observed values of vertical wavelengths and wave amplitudes, the horizontal wavelengths, wave phase and group velocities have been estimated for different wave periods. These results have implications on monitoring of the ubiquitous atmospheric gravity waves generated mainly by the tropospheric weather system of the tropical region from their imprint on the mesospheric turbulence structures.

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Section: Discussionmentioning

confidence: 63%

Propagation of short period (10-40min) atmospheric gravity waves from troposphere to mesosphere over Gadanki, India

Chakravarty

Nagaraja

2015

Journal of Atmospheric and Solar-Terrestrial Physics

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“…The role of the vertical wind shear on IGW absorption, reflection, refraction and entrapment at model boundary conditions in the atmosphere layer, described by the TG equation, has been investigated previously by Dunkerton (1997) and Yuan and Fritts (1989). In the neutrally stratified atmosphere, when the square of the BruntVäisälä frequency ω 2 g = 0, the TG equation reduces to the Orr-Sommerfeld (or Rayleigh) equation (e.g., Onishchenko et al, 2008) describing Kelvin-Helmholtz instability. By assuming the atmospheric perturbations in the form ψ = ψ k exp(−iωt +ik x x+ik z z), the Fourier transform of Eq.…”

Section: Reduced Hydrodynamic Equationsmentioning

confidence: 97%

“…An equation similar to Eq. (19) has been studied analytically and numerically previously (e.g., Onishchenko et al, 2008) plain, vortex streets (the so-called "cat's eyes") and dipole vortices.…”

Section: Convective Cellsmentioning

confidence: 99%

Rolls of the internal gravity waves in the Earth's atmosphere

et al. 2014

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Abstract. The effect of the wind shear on the roll structures of nonlinear internal gravity waves (IGWs) in the Earth's atmosphere with the finite vertical temperature gradients is investigated. A closed system of equations is derived for the nonlinear dynamics of the IGWs in the presence of temperature gradients and sheared wind. The solution in the form of rolls has been obtained. The new condition for the existence of such structures was found by taking into account the roll spatial scale, the horizontal speed and wind shear parameters. We have shown that the roll structures can exist in a dynamically unstable atmosphere.

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“…This results in generation of convective cells with finite poloidal (horizontal) vorticity (e.g. Onishchenko and Pokhotelov, 2012;Onishchenko et al, 2013Onishchenko et al, , 2014a.…”

Section: Introductionmentioning

confidence: 99%

Dust devil vortex generation from convective cells

et al. 2015

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Abstract.We have developed a hydrodynamic theory of the nonlinear stage of dust devil generation in a convectively unstable atmosphere with large-scale seed vertical vorticity. It is shown that convective motion in such an atmosphere transforms into dust devils extremely fast. The strong vortical structure of the dust devils can be formed in a few minutes or even in a fraction of a minute. The formation process strongly depends on the convective instability growth rate and horizontal vorticity.

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Convective cells of internal gravity waves in the earth's atmosphere with finite temperature gradient

Cited by 16 publications

References 19 publications

Propagation of short period (10-40min) atmospheric gravity waves from troposphere to mesosphere over Gadanki, India

Propagation of short period (10-40min) atmospheric gravity waves from troposphere to mesosphere over Gadanki, India

Rolls of the internal gravity waves in the Earth's atmosphere

Dust devil vortex generation from convective cells

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