Middle stratosphere temperature spectra observed with stellar scintillation and in situ techniques

The vertical temperature spectra within the middle stratosphere (20–30 km) was measured using two independent techniques. The first technique involves orbital station observations of star scintillation during their occultation by the Earth's atmosphere. The time spectra of star brightness is then converted into vertical temperature spectra. The second technique consists of in situ measurements of temperature on a ballon-borne gondola. The spectra obtained by these two methods are consistant with each other both on the spectral slope, close to −3, and on the spectral level for scale range between 50 m and 1 km. However, for scales smaller than 50 m, the spectra obtained by scintillation technique display a sharp cut-off that is not observed with balloon measurements. A tentative interpretation of this discrepancy is presented.