On the meteoric head echo radar cross section angular dependence

Abstract

We present radar cross section (RCS) measurements of meteor head echoes observed with the tristatic 930 MHz EISCAT UHF radar system. The three receivers offer a unique possibility to accurately compare the monostatic RCS of a meteor target with two simultaneously probed bistatic RCSs at different aspect angles. Meteoroids from all possible directions entering the common volume monitored by the three receivers are detected, out to an aspect angle of 130° from the meteoroid trajectories. The RCS of individual meteors as observed by the three receivers are equal within the accuracy of the measurements. This is consistent with an essentially isotropic scattering process as has previously been inferred from polarization measurements by S. Close et al. (2002). There is a very weak trend present in our data suggesting that the RCS may decrease at a rate of 0.2 dB per 10° with increasing aspect angle.