Aeronomy: The Relationship Between Mass, Luminosity and Radar Scattering Cross-section for Small-mass Meteors and their Effects on the Mesosphere

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The scientific objective of the study is to estimate the input of meteoric material into Earth's upper atmosphere, which is an important process that affects the ionosphere, thermosphere, mesosphere and atmosphere. Determining the meteoric mass distribution is critical for characterizing the mass input into the mesosphere -- including the metal deposition -- which plays a significant role in the local chemical processes. The meteoric mass is then transported to the middle atmosphere, where coupling with the lower atmosphere occurs. The current models for predicting the speed at which this transport occurs are sensitive to small changes in the total flux of mass from meteors -- which is largely unknown over the observable mass range. The PIs approach of using both optical and radar techniques simultaneously will enable an effective cross-calibration of the two techniques for calculating meteor mass, resulting in a significantly more accurate estimate of the total meteor mass input. In this study, simultaneous optical and radar observations of meteor head echoes are proposed to set constraints on luminosity and ionization efficiencies, respectively, in order to determine meteoroid mass in the 100 microgram to 100 milligram range. Current data sets of common-volume radar and optical observations of meteors from several different radars are be used to address the science goals. Additional campaigns are proposed at specific radar sites, in order to improve and enhance the meteoroid mass and flux estimates based on lessons learned and the limitations of the current data. The main result expected is the production of mass distribution indexes of meteors from the sporadic meteor complex. The use of multiple radars will allow different regions of the sky -- both Southern and Northern -- to be covered and enable the detection of a large range of masses due to the varying sensitivities of the radars. There is a lack of knowledge in several important areas in this whole process and the proposed research will be a valuable tool in solving several issues, such as the formation of noctilucent and polar stratospheric clouds and the presence of meteoric dust. As a result of the review process and careful consideration, this proposal is funded for a period of three years.