Experimental study of the influences of background atmospheric electron density on radar backscatter from meteor trails

Abstract: Meteoroids entering the atmosphere burn up due to friction and form ionized meteor trails at altitudes between 70 km and 120 km approximately. The ionized trails can be detected by radar. Radar measurements have allowed determination of characteristics of both the meteor trails and the atmosphere around the trails. The measured meteor trail decay time is related with the ionized trail’s expansion and the diffusion effects in the atmosphere, which could be used to estimate the neutral gas temperature of the atmosphere at the altitudes of the meteor layer.""This thesis examines one possible influence on meteor decay times, the background atmospheric electron density variations. At the main meteor layer (about 50 to 95 km above Earth’s surface), the ionosphere electron density varies between daytime and nighttime. The meteor decay time dependency on solar zenith angle, time of year and altitude were studied to understand the relation between meteor decay time behaviour and background atmospheric electron density variations. The meteor data came from meteor radar observations at the frequencies 32.55 MHz and 53.5 MHz, at mid-latitude 54°N (Juliusruh, Germany) and polar latitude 69°N (Andenes, Norway), during the year 2008. The influence of meteor decay time variation on the atmosphere temperature estimations is also discussed.