Study on Relationship Between Reflecting Characteristic of Polar Mesosphere Summer Echoes with Frequency

Polar Mesosphere Summer Echoes(PMSE) is a kind of strong radar echoes from altitudes close to the summer mesopause where there is a large amount of charge dust particles with obviously layered structure.In the paper the theory of wave propagation in layered media is used to study the radar signal to noise ratio SNR at 53.5 MHz,225 MHz,and 931 MHz.The results show that the profile of SNR at 53.5 MHz almost agrees with the results observed.With the intensity of the radar echoes reflected by layered structure decreasing greatly with the increasing frequency,the radar echoes become very weak.So,the method of layered media may be one of the important tools to study the generation mechanism of Polar Mesosphere Summer Echoes(PMSE).