CEDAR: Atmospheric Neutral Density Dynamics through Meteor Observations

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This award is an experimental effort to further develop a new measurement technique for estimating neutral densities by using radar observations of meteor trajectories. As meteoroids enter the Earth's atmosphere, they experience deceleration due to atmospheric drag and form meteors that radar can observe, providing a source of information that can independently determine the neutral density of the atmosphere at altitudes of 80 to 140 km. Measurements of neutral densities in this region are very challenging experimentally and this work will fill this gap by using a novel technique. Knowledge of neutral densities is important since low-Earth-orbit satellites experience atmospheric drag that is strongly dependent on densities. The continued accumulation of data characterizing this meteoroid population would also provide improved risk assessment to spacecraft operators and to ground-based users of satellite data. This work will also provide research topics for new graduate students and results from this work will be incorporated into undergraduate and graduate courses in Aeronautics and Astronautics.The latitudinal and temporal variation of neutral density in the mesosphere-lower-thermosphere region between 80 and 140 km in altitude will be studied by conducting a simultaneous meteor radar campaign at two geographically distinct radar facilities and applying a novel statistical technique to derive neutral density values from the detected meteor trajectories. These measurements of atmospheric neutral density will be compared against existing atmospheric models to characterize the origins of short time density variations and to assess the extent that they will couple to density enhancements in the upper atmosphere. The resulting measurements of total neutral density will complement measurements of temperature, winds, plasma, and individual metallic species, and provides an alternative source of data to existing neutral density measurements that are sparse or that depend on different physical assumptions.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.