An Investigation of Turbulence Generation Mechanisms above Deep Convection

Lane, Todd P.; Sharman, Robert; Clark, Terry L.; Hsu, Hsiao-Ming

doi:10.1175/1520-0469(2003)60<1297:aiotgm>2.0.co;2

Cited by 151 publications

(129 citation statements)

References 26 publications

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“…21 K at 18.2 km in the case simulated by Jensen et al (2007). The turbulent mixing may be enhanced by the gravity wave breaking, which results in a vertical extension of the mixing layer (Lane et al, 2003). The colder and heavier air masses, having been detrained in the LS, then descend, resulting in an adiabatic heating of the layer.…”

Section: Origin Of Temperature Diurnal Cycle In the Lower Stratospherementioning

confidence: 96%

“…A very similar effect was detected in brightness temperature by Yang and Slingo (2001), who tentatively attributed it to gravity waves of varying depth. Another process involving wave activity above convective systems is the breaking of gravity waves, generated by thunderstorms on top of their overshooting domes (Alexander et al, 1995;Lane et al, 2001Lane et al, , 2003, leading to the formation of "jumping cirrus" reported by Fujita (1992). As shown by Wang (2004) using a three-dimensional non-hydrostatic cloud model, this process leads to an irreversible diabatic transport of tropospheric materials at 8 m s −1 vertical velocity up to 3-4 km above the cloud anvil, that is, at about 17-18 km altitude in the tropics.…”

Section: Origin Of Temperature Diurnal Cycle In the Lower Stratospherementioning

confidence: 99%

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Impact of land convection on temperature diurnal variation in the tropical lower stratosphere inferred from COSMIC GPS radio occultations

2013

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Following recent studies evidencing the influence of deep convection on the chemical composition and thermal structure of the tropical lower stratosphere, we explore its impact on the temperature diurnal variation in the upper troposphere and lower stratosphere using the high-resolution COSMIC GPS radio-occultation temperature measurements spanning from 2006 through 2011. The temperature in the lowermost stratosphere over land during summer displays a marked diurnal cycle characterized by an afternoon cooling. This diurnal cycle is shown collocated with most intense land convective areas observed by the Tropical Rainfall Measurement Mission (TRMM) precipitation radar and in phase with the maximum overshooting occurrence frequency in late afternoon. Two processes potentially responsible for that are identified: (i) non-migrating tides, whose physical nature is internal gravity waves, and (ii) local cross-tropopause mass transport of adiabatically cooled air by overshooting turrets. Although both processes can contribute, only the lofting of adiabatically cooled air is well captured by models, making it difficult to characterize the contribution of non-migrating tides. The impact of deep convection on the temperature diurnal cycle is found larger in the southern tropics, suggesting more vigorous convection over clean rain forest continents than desert areas and polluted continents in the northern tropics

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Section: Origin Of Temperature Diurnal Cycle In the Lower Stratospherementioning

confidence: 96%

Section: Origin Of Temperature Diurnal Cycle In the Lower Stratospherementioning

confidence: 99%

Impact of land convection on temperature diurnal variation in the tropical lower stratosphere inferred from COSMIC GPS radio occultations

2013

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“…Although wind shears typically exist in convective plume regions, Beres (2004) showed via comparison between linear and nonlinear models that the linear model gives reasonably good results with a mean background wind in the convective plume region. Also, Lane et al (2003) found, using a numerical 3-D cloud-resolving model, that the excited GW spectrum in the intrinsic frame of reference is reasonably symmetric, thereby showing that the shear effect is of smaller importance than the overall Doppler effect of the moving wind frame at the tropopause. Therefore, we calculate the excited GW spectrum in the frame of reference of a constant mean wind in the region of the convective plume, then ray trace the GWs out of that region, as described in Sect.…”

Section: Convective Plume Modelmentioning

confidence: 99%

Reconstruction of the gravity wave field from convective plumes via ray tracing

2009

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Abstract. We implement gravity wave (GW) phases into our convective plume and anelastic ray trace models. This allows us to successfully reconstruct the GW velocity, temperature, and density perturbation amplitudes and phases in the Mesosphere-Lower-Thermosphere (MLT) via ray tracing (in real space) those GWs that are excited from a deep convective plume. We find that the ray trace solutions agree very well with the exact, isothermal, zero-wind, Fourier-Laplace solutions in the Boussinesq limit. This comparison also allows us to determine the normalization factor which converts the GW spectral amplitudes to real-space amplitudes in the ray trace model. This normalization factor can then be used for ray tracing GWs through varying temperature and wind profiles. We show that by adding GW reflection off the Earth's surface, the resulting GW spectrum has more power at larger vertical and horizontal wavelengths. We determine the form of the momentum flux and velocity spectra which allows for easy calculation of GW amplitudes in the MLT and thermosphere. Finally, we find that the reconstructed (ray traced) solution for a deep, convective plume with a duration much shorter than the buoyancy period does not equal the Fourier-Laplace Boussinesq solution; this is likely due to errors in the Boussinesq dispersion relation for very high frequency GWs.

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“…For example, horizontal scales of motion between approximately 50-1000 m will induce a turbulence response from large commercial aircraft (Lane et al 2003); scales of motion that affect light aircraft are even shorter. Thus, some kind of instability or additional process is required to induce a cascade from the relatively long wave scale, down to sub-kilometre scales.…”

Section: Introductionmentioning

confidence: 99%

Trapped mountain waves during a light aircraft accident

Parker¹,

Lane

2013

AMOJ

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On 31 July 2007 a fatal light aircraft crash occurred near Clonbinane, Victoria, Australia and the official investigation concluded that mountain wave turbulence was the likely cause. This study uses three-dimensional numerical modelling and linear wave theory to examine the dynamics of mountain waves during this turbulence event and their role in generating turbulence. Analysis of the observed environment and three-dimensional idealised simulations elucidate the occurrence of trapped mountain waves and their role in creating regions of enhanced turbulence in the vicinity of the aircraft accident. Specifically, these waves perturb layers of low dynamic stability in the upstream flow, promoting turbulence in those layers. A simple ensemble of these three-dimensional simulations is also used to assess the robustness of the model solutions and demonstrate the utility of highresolution ensembles for explicit mountain wave turbulence prediction.

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An Investigation of Turbulence Generation Mechanisms above Deep Convection

Cited by 151 publications

References 26 publications

Impact of land convection on temperature diurnal variation in the tropical lower stratosphere inferred from COSMIC GPS radio occultations

Impact of land convection on temperature diurnal variation in the tropical lower stratosphere inferred from COSMIC GPS radio occultations

Reconstruction of the gravity wave field from convective plumes via ray tracing

Trapped mountain waves during a light aircraft accident

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