Dual Radar Detections of Meteors Using Calibrated EISCAT UHF Data

Abstract

The atmosphere of Earth experiences a continuous entry of particles of various sizes originating from several sources. Meteoroids, which are called meteors when entering the atmosphere, are particles that can be measured by radars through scattering off the meteor head plasma which forms around the meteor. These measurements can give information on the processes the meteor undergoes as it travels through the atmosphere.

The work in this thesis provides a timing calibration of the EISCAT UHF system for meteor studies, calculates the RCS of meteor head echoes using an accurate EISCAT UHF beam pattern and the MAARSY-derived meteor location, proposes and presents a method by which to detect and classify simple ablation, differential ablation, and fragmentation meteor events, and considers the results from this analysis in the context of previous research.

Differential ablation was most successfully classified through the method developed, while simple ablation and fragmentation were more ambiguous. The analysis of differential ablation meteor events shows a clear drop in the radar signal at approximately 100 km altitude, indicating the complete ablation of, for example, Na and K particles in the meteor. A case study of a meteor undergoing fragmentation shows the signature oscillatory pattern originating from two or more fragments moving with different velocities.