Spectral Analysis of Vertical Temperature Profiles Observed by a Lidar in the Upper Stratosphere and the Lower Mesosphere

The Rayleigh lidar with a XeF excimer laser provides accurate temperature profiles in an altitude range from 30 to 70km. The power spectral density of the temperature fluctuation as a function of the vertical wavenumber is determined with these data. Both the stratospheric and mesospheric spectra can be obtained simultaneously. The slopes of the observed spectra are between -2.5 and -3.0, and almost coincide with the published values obtained by the wind observations. The observed spectral density in the upper stratosphere is smaller than that in the lower mesosphere, while the saturation spectrum theory predicts that the saturation spectrum in the upper stratosphere is larger than the lower mesospheric one. Difference between the observed and theoretical spectra are discussed.