Generation mechanisms of convectively induced internal gravity waves in a three-dimensional framework

Choi, Eun Ho; Chun, Hye‐Yeong

doi:10.1007/s13143-014-0005-x

Cited by 8 publications

(4 citation statements)

References 19 publications

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“…(2001) proposed that convection can generate the SGWs mainly through three mechanisms: mechanical oscillation, diabatic heating, and the obstacle or moving mountain effect, and they also suggested a source function to diagnose the three mechanisms. The source function (Choi & Chun, 2014; Lane et al., 2001) can be shown as following:

\begin{matrix} left \\ \frac{{\overset{D}{true}}^{2}}{D t^{2}} ([], ({}, \frac{\partial^{2}}{\partial x^{2}} + \frac{\partial^{2}}{\partial y^{2}}) w^{'} + \frac{\partial}{\partial z} ({}, \frac{1}{\overline{ρ}} \frac{\partial}{\partial z} ((), \overset{ρ}{true} w^{'}))) - \frac{d^{2} U}{d z^{2}} \frac{\overline{D}}{D t} ((), \frac{\partial w^{'}}{\partial x}) - \frac{d^{2} V}{d z^{2}} \frac{\overline{D}}{D t} ((), \frac{\partial w^{'}}{\partial y}) + \\ \frac{d U}{d z} \frac{\overline{D}}{D t} ((), \frac{1}{\overline{ρ}} \frac{d \overset{ρ}{true}}{d z} \frac{\partial w^{'}}{\partial x}) + \frac{d V}{d z} \frac{\overline{D}}{D t} ((), \frac{1}{\overline{ρ}} \frac{d \overset{ρ}{true}}{d z} \frac{\partial w^{'}}{\partial y}) + N^{2} ((), \frac{\partial^{2}}{\partial x^{2}} + \frac{\partial^{2}}{\partial y^{2}}) w^{'} = \\ (\frac{\partial^{2}}{\partial x^{2}} + \frac{\partial^{2}}{\partial y^{2}}) \{\frac{\overset{D}{true}}{D t}\} \end{matrix}

…”

Section: Generation Mechanism Of Sgwsmentioning

confidence: 99%

“…Lane et al (2001) proposed that convection can generate the SGWs mainly through three mechanisms: mechanical oscillation, diabatic heating, and the obstacle or moving mountain effect, and they also suggested a source function to diagnose the three mechanisms. The source function (Choi & Chun, 2014;Lane et al, 2001) can be shown as following: where U(z) and u' are the basic-state and perturbation zonal winds, respectively; V(z) and v' are the basic-state and perturbation meridional winds, respectively; w' and θ' are the perturbations of the vertical wind and potential temperature respectively; 𝐴𝐴 𝜌𝜌 and 𝐴𝐴 𝜃𝜃 are the basic-state density and potential temperature, respectively; g is the gravitational acceleration. The forcing terms F u , F v , F w , F θ , and Q are expressed as follows:…”

Section: Generation Mechanism Of Swgs By Unbalanced Flowmentioning

confidence: 99%

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Generation Mechanism for Stratospheric Gravity Waves by Unbalanced Flow in Tropical Cyclones

Wang,

Zhang,

Wang

et al. 2023

Geophysical Research Letters

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The generation mechanism of stratospheric gravity waves (SGWs) in tropical cyclones (TCs) is investigated with an idealized experiment using numerical model. The results show that there are two peaks of SGW amplitude during the mature period of TC, one above the eyewall and the other above the rainband. The SGWs can only exist in unbalanced flow, so a simplified balance equation suitable for the special structure of the TC is proposed to investigate the SGWs. Diagnosis of this equation shows there is significant unbalanced flow around the eyewall and rainband caused by the convection and the vertical shear between outflow and compensating inflow. Diagnosis of the source function indicates that diabatic heating and mechanical oscillations are the main mechanisms generating the SGWs above the eyewall and rainband. The Kelvin–Helmholtz instability induced by vertical shear also makes a non‐negligible contribution to the generation of SGWs above the rainband.

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\begin{matrix} left \\ \frac{{\overset{D}{true}}^{2}}{D t^{2}} ([], ({}, \frac{\partial^{2}}{\partial x^{2}} + \frac{\partial^{2}}{\partial y^{2}}) w^{'} + \frac{\partial}{\partial z} ({}, \frac{1}{\overline{ρ}} \frac{\partial}{\partial z} ((), \overset{ρ}{true} w^{'}))) - \frac{d^{2} U}{d z^{2}} \frac{\overline{D}}{D t} ((), \frac{\partial w^{'}}{\partial x}) - \frac{d^{2} V}{d z^{2}} \frac{\overline{D}}{D t} ((), \frac{\partial w^{'}}{\partial y}) + \\ \frac{d U}{d z} \frac{\overline{D}}{D t} ((), \frac{1}{\overline{ρ}} \frac{d \overset{ρ}{true}}{d z} \frac{\partial w^{'}}{\partial x}) + \frac{d V}{d z} \frac{\overline{D}}{D t} ((), \frac{1}{\overline{ρ}} \frac{d \overset{ρ}{true}}{d z} \frac{\partial w^{'}}{\partial y}) + N^{2} ((), \frac{\partial^{2}}{\partial x^{2}} + \frac{\partial^{2}}{\partial y^{2}}) w^{'} = \\ (\frac{\partial^{2}}{\partial x^{2}} + \frac{\partial^{2}}{\partial y^{2}}) \{\frac{\overset{D}{true}}{D t}\} \end{matrix}

…”

Section: Generation Mechanism Of Sgwsmentioning

confidence: 99%

Section: Generation Mechanism Of Swgs By Unbalanced Flowmentioning

confidence: 99%

Generation Mechanism for Stratospheric Gravity Waves by Unbalanced Flow in Tropical Cyclones

Wang,

Zhang,

Wang

et al. 2023

Geophysical Research Letters

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“…There seems to be a close connection between the characteristics of the convection cells and the spectrum of IGWs generated by convection (e.g., Alexander and Holton 1997;Piani et al 2000;Song et al 2003;Beres and Alexander 2004;Choi and Chun 2014), which is the basis for the thermal forcing mechanism. The spectrum of IGWs generated by convection depends on the latent heat released, properties of convection in the lower troposphere and the environmental wind (Beres and Alexander 2004;Beres et al 2005).…”

Section: Introductionmentioning

confidence: 97%

Application of the Compressible, Nonhydrostatic, Balanced Omega Equation in Estimating Diabatic Forcing for Parameterization of Inertia–Gravity Waves: Case Study of Moist Baroclinic Waves Using WRF

Haghighatnasab

Mirzaei

Mohebalhojeh

et al. 2020

Journal of the Atmospheric Sciences

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The parameterization of inertia–gravity waves (IGWs) is of considerable importance in general circulation models. Among the challenging issues faced in studies concerned with parameterization of IGWs is the estimation of diabatic forcing in a way independent of the physics parameterization schemes, in particular, convection. The requirement is to estimate the diabatic heating associated with balanced motion. This can be done by comparing estimates of balanced vertical motion with and without diabatic effects. The omega equation provides the natural method of estimating balanced vertical motion without diabatic effects, and several methods for including diabatic effects are compared. To this end, the assumption of spatial-scale separation between IGWs and balanced flows is combined with a suitable form of the balanced omega equation. To test the methods constructed for estimating diabatic heating, an idealized numerical simulation of the moist baroclinic waves is performed using the Weather Research and Forecasting (WRF) Model in a channel on the f plane. In overall agreement with the diabatic heating of the WRF Model, in the omega-equation-based estimates, the maxima of heating appear in the warm sector of the baroclinic wave and in the exit region of the upper-level jet. The omega-equation-based method with spatial smoothing for estimating balanced vertical motion is thus presented as the proper way to evaluate diabatic forcing for parameterization of IGWs.

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“…Thunderstorms are a major source of gravity waves including all three types of mechanisms described in section 2.2.2; however, latent heat forcing seems to play a significant role in that. Previous model-based studies have highlighted the large perturbations created in the atmosphere due to thunderstorms [15], [16], [19], [21], [55]. There are numerous observational studies which have showed the basic characteristics of the gravity waves generated by thunderstorms but have not developed any quantified relationship between the variables involved using any long-term data for developing generalised relationships [10], [45], [46], [52], [74], [104].…”

Section: Discussionmentioning

confidence: 99%

Gravity waves generated by thunderstorms

Athreyas¹,

Bramha²

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Generation mechanisms of convectively induced internal gravity waves in a three-dimensional framework

Cited by 8 publications

References 19 publications

Generation Mechanism for Stratospheric Gravity Waves by Unbalanced Flow in Tropical Cyclones

Generation Mechanism for Stratospheric Gravity Waves by Unbalanced Flow in Tropical Cyclones

Application of the Compressible, Nonhydrostatic, Balanced Omega Equation in Estimating Diabatic Forcing for Parameterization of Inertia–Gravity Waves: Case Study of Moist Baroclinic Waves Using WRF

Gravity waves generated by thunderstorms

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