Long-Term Distribution of Meteors in a Solar Cycle Period Observed by VHF Meteor Radars at Near-Equatorial Latitudes

摘要

We investigated meteor height and number of meteor echoes over a 13-year observation period, with the data recorded by the meteor wind radar systems in Kototabang (0.20°S, 100.32°E) and Biak (1.17°S, 136.10°E), Indonesia. We aimed to investigate the changes in meteor peak height according to solar activity, represented by the solar radio index F10.7, and the number of solar sunspots, R, compared with the empirical results of the Mass Spectrometer Incoherent Scatter Extending (MSISE) and Committee on Space Research International Reference Atmosphere models. We found that (i) the daily meteor count rates at both sites in the period from 2003 to 2016 could be used to determine the dynamics in the upper atmosphere, where peak conditions occurred in the middle of the year; (ii) through a statistical approach using the normal distribution function, the variation in meteor peak height showed a positive correlation with the trend in solar activity; and (iii) comparison between the two empirical models and our observations showed two points where annual air density seemed to have a clear relationship with peak meteor height. In addition, the annual neutral density pattern of the model was related to the daily meteor count every year, although it showed a pattern opposite to the solar activity trends.