Backscatter observations of the mesosphere (62–86 km), using the 50 MHz coherent scatter radar at Jicamarca, Peru (12°S, 77°W), are analyzed to obtain tidal and prevailing wind components. The observation periods are four 48‐hour intervals covering December 20–22, 1976, and April 11–13, July 15–17, and October 3–5, 1977. The effects of missing nighttime data on the 12‐ and 24‐hour estimates are taken into account. The diurnal and semidiurnal tidal components appear to show an evanescent mode or higher order propagating modes superimposed on the main diurnal (1,1) mode and the main semidiurnal (2,2) mode, respectively. There are a few indications of complete phase reversal from one height to the next, indicating the presence of standing wave patterns. The diurnal tide amplitudes never realize the amplitude growth with height predicted by theory partly due to interference effects and other loss processes at work in the upper mesosphere.

Abstract. In the present communication a novel method is presented to derive the altitude profile of Brunt-Väisälä period from the ascent rate profile of sounding balloons. The basic premise of the present method is that the oscillations in the ascent rate of the balloon will have the signature of Brunt-Väisälä frequency, which can be retrieved by using sophisticated spectral tools. We employ wavelet transforms to arrive at the Brunt-Väisälä period profile. Comparison of retrieved Brunt-Väisälä periods with the values derived from the temperature data available from the same radiosonde ascent shows good agreement. Retrieving the atmospheric temperature from the height profile of Brunt-Väisälä period is also discussed in the present communication. We have shown that it is possible to estimate the Brunt-Väisälä period and temperature profiles from the rawinsonde ascent rate data alone where temperature sounding is not available.

No abstract

No abstract

No abstract