Study of the turbulence and inner waves in the stratosphere based on the observations of stellar scintillations from space: A model of scintillation spectra

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

“…We assume that ν is the sum of two statistically independent components corresponding to the anisotropic and isotropic irregularities, W (κ) and K (κ), respectively (Gurvich and Brekhovskikh, 2001):…”

“…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).…”

“…Due to exponential decrease of air density with altitude, the effective thickness of the atmosphere along the ray in occultation experiments is L ef = √ π R E H 0 ≈ 350 km (Gurvich and Brekhovskikh, 2001;Hubbard et al, 1978), where R E is the Earth radius and H 0 ≈ 6 km is the atmospheric scale height. This thickness is 10 times smaller than the distance L between ray perigee and the satellite.…”

“…An equivalent phase screen, which models phase fluctuations at the exit from the atmosphere, is placed in the plane perpendicular to the incident rays and passing through V. Kan et al: Variable anisotropy of small-scale stratospheric irregularities the Earth center. Properties of the phase screen and its applicability to satellite experiments are discussed in detail in e.g., Gurvich and Brekhovskikh (2001), Gurvich (1984) and Hubbard et al (1978). The limitation of phase fluctuations of light in the atmosphere due to changes in the orientation of anisotropic inhomogeneities along the line of sight when η > η cr = √ R E /H 0 ≈ 30 (Gurvich and Brekhovskikh, 2001;Gurvich, 1984) is taken into account in our theoretical calculations.…”

“…Based on these data, an empirical model of the 3-D wave-number spectrum of air density irregularities has been developed. 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).…”