[1] Exploitation of stellar scintillation allows studying air density irregularities in the stratosphere. In this paper, we develop a methodology for reconstruction of internal gravity wave (IGW) and turbulence parameters using scintillation measurements by the Global Ozone Monitoring by Occultation of Star (GOMOS) fast photometers on board the Envisat satellite. The forward model is based on a two-component spectral model of air density irregularities: the first component corresponds to the gravity wave spectrum, while the second one describes locally isotropic turbulence resulting from internal gravity wave breaking. The retrieval of parameters of IGW and turbulence spectra is based on the maximum likelihood method. The developed algorithm is tested on simulated and real data, and its accuracy is assessed. It is shown that the measured scintillation spectra are in good agreement with the proposed model and that structure characteristics and inner and outer scales of the anisotropic component can be reconstructed from scintillation spectra. The developed method can provide information about global distribution of parameters of IGW and turbulence spectra in the stratosphere at altitudes from 25 to 50 km.Citation: Sofieva, V. F., A. S. Gurvich, F. Dalaudier, and V. Kan (2007), Reconstruction of internal gravity wave and turbulence parameters in the stratosphere using GOMOS scintillation measurements,

Abstract. Turbulence parameters in the tropo-stratosphere are analyzed using high-resolution balloon temperature measurements collected during the MUTSI (MU radar, Temperature sheets and Interferometry) campaign which took place near the Middle and Upper atmosphere (MU) radar (Japan, 35 • N, 136 • E) in May 2000. Vertical profiles of the specific dissipation rate of turbulent kinetic energy, ε, and turbulent diffusivity, K, are estimated from the Thorpe lengthscale, L T . The last is obtained by using two methods. The first one consists of measuring directly L T by reordering the potential temperature profiles. The second method is based on estimates of the temperature structure constant, C 2 T . A relationship between L T and C 2 T can be found by assuming either adiabatic vertical displacements or a model based on turbulent energy balance consideration. Analysis shows that the adiabatic assumption gives indirect estimates of L T more consistent with direct measurements. We also found that vertical profiles of analyzed turbulence characteristics show substantial intermittency, leading to substantial scatter of the local, median and average values. General trends correspond to a decrease in ε and K from the boundary layer up to altitudes 20-25 km. Layers of increased turbulence are systematically observed in the tropo-stratosphere, which may be produced by instabilities of temperature and wind profiles. These maxima may substantially increase local values of turbulence diffusivity.

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[1] Odd nitrogen species play an important role in the stratospheric ozone balance through catalytic ozone destruction. A layer of strongly enhanced NO 2 was detected in the north polar mesosphere by the GOMOS/ ENVISAT stellar spectrometer in mid-January 2004. Large NO 2 enhancements in the polar winter mesosphere have been previously reported by several authors and have been attributed to NO production by solar proton or by energetic electron precipitations. The simultaneous occurrence of an intense mesospheric warming observed by the SABER/ TIMED instrument indicates that a strong air descent occurred in the polar region, transporting a large quantity of NO from the upper mesosphere-lower thermosphere to the lower mesosphere. The proposed mechanism may have a significant contribution to the budget of polar stratospheric ozone. Citation: Hauchecorne, A., J