The Meteoroid Input Function and predictions of mid-latitude meteor observations by the MU radar

Abstract

The majority of extraterrestrial particles entering Earth’s atmosphere originate from the Sporadic Meteoroid Complex (SMC) and are associated with many mesospheric layer phenomena. The Meteoroid Input Function (MIF) is a model that has been developed with the purpose of understanding the temporal and spatial variability of the meteoroid impact in the atmosphere. The MIF has been shown to accurately predict the seasonal and diurnal variations of the meteor flux observed by High Power Large Aperture (HPLA) radars at various geographic locations, including the Arecibo Observatory (AO) and the Poker Flat Incoherent Scatter Radar (PFISR). For this, the model requires the assessment of a potential observational bias of the particular HPLA radar utilized: the minimum detectable radar cross-section (RCS). The RCS sensitivity threshold provides a metric to characterize the radar system’s ability to detect particles with a given mass and speed. In this paper, the MIF model was used to predict meteor properties (e.g. the distributions of areal density, speed, and radiant location) observed by the Middle and Upper atmosphere (MU) radar while leveraging the system’s interferometric capability to address the model’s ability to predict meteor observations at middle geographic latitudes and for a radar operating frequency in the low VHF band. This study demonstrates that the MIF accurately considered the speed and sporadic source distributions for the portion of the meteoroid population observable by the MU radar, and the applicability of the MIF to the MU system increases the confidence of using it as a global model.