Radiant measurement accuracy of micrometeors detected by the Arecibo 430 MHz Dual-Beam Radar

[摘要] Precise knowledge of the angle between the meteor vector velocity and theradar beam axis is one of the largest source of errors in the AreciboObservatory (AO) micrometeor observations. In this paper we study ~250high signal-to-noise ratio (SNR) meteor head-echoes obtained using thedual-beam 430 MHz AO Radar in Puerto Rico, in order to reveal thedistribution of this angle. All of these meteors have been detected first bythe radar first side lobe, then by the main beam and finally seen in the sidelobe again. Using geometrical arguments to calculate the meteor velocity inthe plane perpendicular to the beam axis, we find that most of the meteorsare travelling within ~15° with respect to the beam axis, inexcellent agreement with previous estimates. These results suggest thatmeteoroids entering the atmosphere at greater angles may deposit theirmeteoric material at higher altitudes explaining at some level the missingmass inconsistency raised by the comparisson of meteor fluxes derived fromsatellite and traditional meteor radar observations. They also may be thesource of the observed high altitude ions and metalic layers observed byradars and lidars respectively.

[学科分类] 大气科学