ocr: 1A - - - - dE dt to interpret ity waves in the bere are mono- Infinitely in time alysis and mono- - - successfuli in obser- ational stug i - - 82 84, 1989). On one hand, sectral analysis has cd the universal character 'a-3 power law of the vertical wave-number spec- um (Endlich et al., 1969; Yamanaka, 1985; Smith al., 1985, 1987; Tsuda et al, 1989) from data stained in a: sufliciently broad height range and for suitably long observational period by using high- solution radiosondes and MST radars. This uni- :rsal: spectrall behaviour has beeni interpreted as satu- tion of internal gravity waves ...
