PLANETARY-SCALE DISTURBANCES AND THEIR VERTICAL PROPAGATION IN THE LOWER IONOSPHERE

Using phase and amplitude recordings of the 100 kHz Sky wave signal received in Wuchang(30.3°N,114.2°E) during winter in 1985 and 1986,a study of planetary-scale wave disturbance and their vertical propagation is made by use of wavelet analysis.It shows that there are mainly distinct disturbances of planetary-scale wave with period from 5 to 10 days and from 10 to 20 days at different altitudes of 75 km and 95 km respectively.The perturbing amplitudes increase with height,[and their increasement are smaller than those of theoretical'estimations. In addition,there is a similar tendency for the change of disturbance of either at 75 km or at 95 km.According to the propagation theory and related experimental data,planetary-scale waves with vertical wavelengths of the order of 40 to 60 km and a velocity of about 2.7-3.7 km per day appear to travel in the vertical direction.