An Algorithm to Separate Ionospheric Turbulence Radar Echoes From Those of Meteor Trails in Large Data Sets.

Coherent scatter echoes from disintegrating meteors and from the unstable ionospheric E‐region can overlap considerably between 90 and 110 km altitudes. As the physical origin of plasma irregularities produced by meteor trails differs starkly from that of E‐region auroral irregularities, this has consequences for winds as well as electrodynamic studies, thereby introducing a need to distinguish between the two types of echoes. To that goal, we have developed a novel separation algorithm to automatically sort through arbitrarily large data sets in the region of overlap. This proves very useful when the 3D location of echoes is available. The algorithm uses a definition of crowding, or clustering, in both time and space and has been developed and tested with a comprehensive data set obtained from the recently built Canadian icebear 3D radar. We discuss the characteristics belonging to the two classes of echoes, and present statistical results about the location of each type of echo as a function of conditions. Our proposed algorithm can be applied to any coherent scatter echo data with high resolution 3D location information. Plain Language Summary: Radars measure turbulence in space plasma by bouncing a signal off of sharp plasma density gradients in the ionosphere. For decades, such coherent radars have been useful tools to investigate the ionosphere. However, when probing E‐region plasma, a coherent radar will pick up plasma produced by meteors as they enter Earth's atmosphere. We have developed an automatic algorithm to separate meteor trail echoes, as they are called, from space plasma measurements. We demonstrate the efficiency of this algorithm on the icebear 3D data set, which has an unprecedented resolution, and offers accurate 3D location data for space plasma turbulence. Key Points: Using new data from icebear 3D, we find that ionospheric turbulence overlap with meteor trail echoes between 90 and 110 km altitudeThe starkly different patterns of clustering in time and space of high latitude ionospheric turbulence and meteoric echoes are used to distinguish the echo typesThe spatial and temporal separation between observed meteor trail echoes is normally several orders of magnitude above that of ionospheric turbulence echoes at high latitudes [ABSTRACT FROM AUTHOR]