Radar meteor atmospheric speeds determined from echo profile measurements

A backscatter radar echo from meteoric ionization is produced from the contributions from successive Fresnel zones as the meteor passes the specular condition. The time variation of the reflection coefficient given in terms of the Fresnel Function is related to the creation rate of zones and hence to meteoroid atmospheric speed. Such echo-profile speeds have been measured using the AMOR facility (New Zealand) and compared with meteoroid speeds simultaneously obtained using both spaced—station timing and whole—profile Fresnel oscillation patterns. The close agreement achieved confirms this simple technique—available to single station radar systems—as valuable in establishing meteoroid speeds.