Using WKB method and full-wave method to discuss infrasonic wave´s resonance-peaks

Using HF-Doppler detector (38.83degreesN, 121.50degreesE) we can continuously observe infrasonic wave. The period of infrasonic wave observed at ionospheric height is 2-5 minutes, and there are two distinctive resonance-peaks in spectrum, one at 3.5min the other at 4.5min. Using WKB method we can get the solution of undulate equation, but this method is unadapted at the height where the features of atmosphere is unstable and the result has a considerable error to practice. However Full-wave method can successfully explain the fine structure of infrasonic wave´s spectrum. At the end of this paper, we discuss some results of Full-wave method.