Reconstruction of internal gravity wave and turbulence parameters in the stratosphere using GOMOS scintillation measurements

Sofieva, Viktoria; Gurvich, A. S.; Dalaudier, Francis; Kan, V.

doi:10.1029/2006jd007483

Cited by 40 publications

(140 citation statements)

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“…In previous works, a phenomenological 3-D model with constant anisotropy was used for characterization of the anisotropic component W (Gurvich and Brekhovskikh, 2001;Gurvich and Kan, 2003a, b;Sofieva et al, 2007aSofieva et al, , b, 2009. Since several studies mentioned above indicate a variable anisotropy growing with the scale of irregularities (the results of this work also support this, see below) we will use for W the model with variable anisotropy, which depends on the vertical scale (Gurvich and Chunchuzov, 2008a, b).…”

Section: A Model Of the 3-d Spectrum Of Atmospheric Irregularitiesmentioning

confidence: 99%

“…We use the decay function in the form: φ = 1 + κ 2 z κ 2 z,W −1 (Gurvich and Kan, 2003a, b;Sofieva et al, 2007a). The 3-D spectrum (Eq.…”

Section: A Model Of the 3-d Spectrum Of Atmospheric Irregularitiesmentioning

confidence: 99%

“…For description of scintillations, K is characterized by two parameters: the structure characteristic C K and the inner scale l K = 5.92/κ K (Tatarskii, 1971). Insufficient sampling frequency of the GOMOS photometers prevents reconstruction of l K from the scintillation spectra (Sofieva et al, 2007a(Sofieva et al, , 2013. We will therefore use the diffraction approximation for modeling isotropic scintillation spectra, i.e., l K ρ F = √ 2π λL ≈ 3.5 m, where ρ F is the Fresnel scale, L is the distance from the ray perigee to the detector (for GOMOS, L ≈ 3225 km).…”

Section: A Model Of the 3-d Spectrum Of Atmospheric Irregularitiesmentioning

confidence: 99%

“…Stellar scintillations in occultation experiments are widely used for probing the atmospheric irregularities of planets and their satellites (Hubbard et al, 1988;Raynaud et al, 2004) and the Earth atmosphere (Gurvich and Kan, 2003a, b;Gurvich et al, 2007;Sofieva et al, 2007aSofieva et al, , b, 2009). The phase screen approximation (Gurvich, 1984;Hubbard et al, 1978) and the theory of weak scintillations (Tatarskii, 1961(Tatarskii, , 1971 provide the basis for analyses of scintillation measurements and reconstructing the parameters of atmospheric irregularities.…”

Section: Introductionmentioning

confidence: 99%

“…In this spectrum, the model of saturated gravity waves is used for description of the anisotropic component, and the Kolmogorov model is used for the description of the isotropic component (Gurvich and Brekhovskikh, 2001;Gurvich and Kan, 2003b). The methodology for reconstructing the parameters of the 3-D model of atmospheric irregularities from scintillation measurements has been successfully applied for analyses of observations on board the MIR station (Gurvich and Kan, 2003a, b), and then for mass reconstruction of the atmospheric irregularity parameters from measurements by the GOMOS fast photometers on board the Envisat satellite (Sofieva et al, 2007a(Sofieva et al, , 2009). This method allows reconstructing all parameters of the 3-D spectral model, except for the anisotropy coefficient η of the anisotropic component (η is defined as a ratio of characteristic horizontal to vertical scale) and therefore η = Const 1 was assumed in retrievals.…”

Section: Introductionmentioning

confidence: 99%

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Variable anisotropy of small-scale stratospheric irregularities retrieved from stellar scintillation measurements by GOMOS/Envisat

2014

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Abstract. In this paper, we consider possibilities for studying the anisotropy of small-scale air density irregularities using satellite observations of bi-chromatic stellar scintillations during tangential occultations. Estimation of the anisotropy coefficient (the ratio of the characteristic horizontal to vertical scales) and other atmospheric parameters is based on the comparison of simulated/theoretical and experimental autospectra and coherency spectra of scintillation. Our analyses exploit a 3-D model of the spectrum of atmospheric inhomogeneities, which consists of anisotropic and isotropic components. For the anisotropic component, a spectral model with variable anisotropy is used. Using stellar scintillation measurements by GOMOS (Global Ozone Monitoring by Occultation of Stars) fast photometers, estimates of the anisotropy coefficient are obtained for atmospheric irregularities with vertical scales of 8-55 m at altitudes of 43-30 km. It is shown that the anisotropy increases from about 10 to 50 with increasing vertical scales.

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Section: A Model Of the 3-d Spectrum Of Atmospheric Irregularitiesmentioning

confidence: 99%

“…We use the decay function in the form: φ = 1 + κ 2 z κ 2 z,W −1 (Gurvich and Kan, 2003a, b;Sofieva et al, 2007a). The 3-D spectrum (Eq.…”

Section: A Model Of the 3-d Spectrum Of Atmospheric Irregularitiesmentioning

confidence: 99%

Section: A Model Of the 3-d Spectrum Of Atmospheric Irregularitiesmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Variable anisotropy of small-scale stratospheric irregularities retrieved from stellar scintillation measurements by GOMOS/Envisat

2014

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Geophysical flows with anisotropic turbulence and dispersive waves: flows with stable stratification

Galperin

Sukoriansky

2010

Ocean Dynamics

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The quasi-normal scale elimination (QNSE) is an analytical spectral theory of turbulence based upon a successive ensemble averaging of the velocity and temperature modes over the smallest scales of motion and calculating corresponding eddy viscosity and eddy diffusivity. By extending the process of successive ensemble averaging to the turbulence macroscale one eliminates all fluctuating scales and arrives at models analogous to the conventional Reynolds stress closures. The scale dependency embedded in the QNSE method reflects contributions from different processes on different scales. Two of the most important processes in stably stratified turbulence, internal wave propagation and flow anisotropization, are explicitly accounted for in the QNSE formalism. For relatively weak stratification, the theory becomes amenable to analytical processing revealing just how increasing stratification modifies the flow field via growing anisotropy and gravity wave radiation. The QNSE theory yields the dispersion relation for internal waves in the presence of turbulence and provides a theoretical reasoning for the Gargett et al. (J Phys Oceanogr 11:1258-1271 scaling of the vertical shear spectrum. In addition, it shows that the internal wave breaking and flow anisotropization void the notion of the critical Richardson number at which turbulence is fully suppressed. The isopycnal and diapycnal viscosities and diffusivities can be expressed in the form of the Richardson diffusion laws thus providing a theoretical framework for the Okubo dispersion diagrams. Transitions in the spectral slopes can be associated with the turbulence-and wave-dominated ranges and have direct implications for the transport processes. We show that only quasi-isotropic, turbulence-dominated scales contribute to the diapycnal diffusivity. On larger, buoyancy dominated scales, the diapycnal diffusivity becomes scale independent. This result underscores the well-known fact that waves can only transfer momentum but not a scalar and sheds a new light upon the Ellison-Britter-Osborn mixing model. It also provides a general framework for separation of the effects of turbulence and waves even if they act on the same spatial and temporal scales. The QNSE theory-based turbulence models have been tested in various applications and demonstrated reliable performance. It is suggested that these models present a viable alternative to conventional Reynolds stress closures.

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Global distribution of C_T² at altitudes 30–50 km from space‐borne observations of stellar scintillation

Gurvich

Sofieva

Dalaudier

2007

Geophysical Research Letters

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Locally isotropic turbulence in the stratosphere consists of isolated sporadic patches with random values of temperature structure characteristic CT2. Stellar scintillations measured aboard GOMOS/ENVISAT through the Earth atmosphere provided the first global distribution of the effective characteristic CT,eff2 averaged along sounding ray. For zonal mean, the largest values are achieved in winter polar regions. This observed intense turbulence is probably related to the polar night jet. Relatively weak turbulence is observed at low latitudes. Turbulence intensity map is shown for altitude 42 km in the latitude band ±35°, where the maxima follow the sub‐solar latitude, with enhancements located mainly over continents. Turbulence enhancements are not related with orography. Despite a noticeable correlation with typical regions of deep convection, the overall distribution of CT,eff2 displays a more complicated structure. Analyzed data suggest that the main turbulence sources, at altitudes ∼40 km, are instabilities of stratospheric circulation and gravity wave breaking.

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Reconstruction of internal gravity wave and turbulence parameters in the stratosphere using GOMOS scintillation measurements

Cited by 40 publications

References 43 publications

Variable anisotropy of small-scale stratospheric irregularities retrieved from stellar scintillation measurements by GOMOS/Envisat

Variable anisotropy of small-scale stratospheric irregularities retrieved from stellar scintillation measurements by GOMOS/Envisat

Geophysical flows with anisotropic turbulence and dispersive waves: flows with stable stratification

Global distribution of C_T² at altitudes 30–50 km from space‐borne observations of stellar scintillation

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Reconstruction of internal gravity wave and turbulence parameters in the stratosphere using GOMOS scintillation measurements

Cited by 40 publications

References 43 publications

Variable anisotropy of small-scale stratospheric irregularities retrieved from stellar scintillation measurements by GOMOS/Envisat

Variable anisotropy of small-scale stratospheric irregularities retrieved from stellar scintillation measurements by GOMOS/Envisat

Geophysical flows with anisotropic turbulence and dispersive waves: flows with stable stratification

Global distribution of CT2 at altitudes 30–50 km from space‐borne observations of stellar scintillation

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Global distribution of C_T² at altitudes 30–50 km from space‐borne observations of stellar scintillation