EGU2020-9587, updated on 12 Jun 2020
https://doi.org/10.5194/egusphere-egu2020-9587
EGU General Assembly 2020
© Author(s) 2020. This work is distributed under
the Creative Commons Attribution 4.0 License.

Specular meteor observations and full wave scattering modelling: observing faint meteors

Gunter Stober1, Peter Brown2,3, Carsten Schult4, Rob Weryk5, Margaret Campbell-Brown2,3, and Petr Pokorny6
Gunter Stober et al.
  • 1University Bern, Institute of Applied Physics, Microwave Physics, Bern, Switzerland (gunter.stober@iap.unibe.ch)
  • 2Dept. of Physics and Astronomy, University of Western Ontario, London, Ontario, Canada N6A 3K7
  • 3Centre for Planetary Science and Exploration, University of Western Ontario, London, Ontario, Canada N6A 5B8
  • 4Leibniz-Institute of Atmospheric Physics, Kühlungsborn, Germany
  • 5Institute for Astronomy, University of Hawaii, Honolulu HI 96822, USA
  • 6Heliophysics Science Division, NASA/Goddard Space Flight Center, Greenbelt, Maryland, 20071, USA

There is a continuous flux of meteoroids entering the Earth's atmosphere, which are decelerated and heated by collisions with atmospheric molecules, and, depending on the meteoroid kinetic energy, they vaporize and form an ambipolar diffusing plasma trail, which is easily detectable using radar remote sensing. Specular meteor observations are a widely used radar technique to measure winds at the Mesosphere and Lower Thermosphere (MLT). The altitude dependent lifetime (decay time) of the meteor plasma columns provides valuable information about the mean temperature of the atmosphere.  Part of the success of these systems is based on the efficient scattering process compared to meteor head echoes.

Here we present observations with the Middle Atmosphere Alomar Radar System to detect the faintest observable meteors using the specular geometry, but a focused beam with a beamwidth of 3.6° and the full power of 866kW of the system. We compare our observations to an orbital dynamics model of JFC comets and derive a meteor velocity distribution for the observed population.

Further, we performed extensive modeling using a full-wave scattering model based on the model presented in Poulter and Baggaley, 1977. We conducted extensive simulations with the full-wave scattering model to investigate how different plasma distributions would affect the detectability of the meteoric plasma cylinders considering the initial trail radius, diffusion, and electron line density. The obtained reflection coefficients are validated with the triple frequency CMOR (Canadian Meteor Orbit Radar) measurements convolving them with the Fresnel integrals. Our results indicate that the plasma distribution can significantly alter the detectability. Further, the model shows that the observed decay time depends on the polarization of the transmitted wave relative to the meteor trajectory, which also revealed resonance effects for certain critical plasma frequencies. 

How to cite: Stober, G., Brown, P., Schult, C., Weryk, R., Campbell-Brown, M., and Pokorny, P.: Specular meteor observations and full wave scattering modelling: observing faint meteors , EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-9587, https://doi.org/10.5194/egusphere-egu2020-9587, 2020

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