Radio?Echo Observations of Meteors in the Antarctic

Abstract

Radio observations of meteors have been made at Mawson on the Antarctic continent since 1957, with a coherent pulse radar equipment operated at a frequency of 34 Mc/s. Heights and directions of reflection points are available for about 10% of the echoes, and temporal variations in these characteristics, together with the diurnal variations in the total echo rate, are analysed and discussed. All the variations observed in these characteristics agree with predictions based on a three-source model for the distribution of the radiants of sporadic meteors. This model distribution, which is symmetrical about the ecliptic, consists of a broad apex source and more concentrated sources near the Sun and antisun. The integrated intensities of the three sources are found to be approximately equal. There is evidence that the meteor echo rate is depressed at times of radio black-out, and it is suggested that periods of exceptionally high meteor activity observed during the summer months could be caused by abnormal ionospheric conditions.