Comparison of Interferometric and Multistatic Observations on Meteors with the EISCAT Incoherent Scatter Radars

Detta är en Master-uppsats från Luleå/Department of Computer Science, Electrical and Space Engineering

Sammanfattning: Meteor studies conducted with radars are an important research topic due to the
meteoroids’ threat against the infrastructure in space. The different radar designs,
which can be used for these studies, have different benefits and are investigating
the meteor process in the Earth’s atmosphere from different aspects. The EISCAT
Scientific Association currently utilizes their incoherent scatter radars as so-called
High Power Large Aperture radars, with which it is possible to extract meteor
information based on the ionisation of ambient atmospheric particles during the
meteoroid entry process.
This Thesis analyses a data set of meteors seen by the mainland VHF radar near
Tromsø, Norway, and a temporary EISCAT_3D VHF demonstrator array, "Bolt",
in Kiruna, Sweden. The analysis is focused on meteor properties such as diurnal
meteor count rate, altitude distribution and velocity studies. By combining bi-static
measurement with interferometry, the antenna mode and experimental geometry
offer new techniques and possibilities in studying the vector velocities of meteor head
echoes in a wider altitude range than for the earlier tri-static EISCAT UHF radar.
This work shows that the VHF demonstrator array in Kiruna was capable for
unique and sophisticated meteor observations and studies. The results fit very well
with the expected meteor properties; The meteor head echo count rate for each
observational day shows a nice diurnal shape. The altitude distribution of meteor
head echoes, seen by the radars, contributes to the on-going meteor studies about the
dependency on atmospheric variations. The diurnal variation of the three velocity
components of each meteor extracted from the observations agree with the known
meteor influx behaviour.