• Solar Cycle and Long-Term Trends in the Observed Peak of the Meteor Altitude Distributions by Meteor Radars 

      Dawkins, E.C.M.; Stober, G.; Janches, D.; Carrillo-Sánchez, J.D.; Lieberman, R.S.; Jacobi, C.; Moffat-Griffin, T.; Mitchell, N.J.; Cobbett, N.; Batista, P.P.; Andrioli, V.F.; Buriti, R.A.; Murphy, D.J.; Kero, J.; Gulbrandsen, Njål; Tsutsumi, M.; Kozlovsky, A.; Kim, J.H.; Lee, C.; Lester, M. (Journal article; Tidsskriftartikkel; Peer reviewed, 2023-01-25)
      The mesosphere/lower thermosphere (MLT, 80–100 km) region is an important boundary between Earth's atmosphere below and space above and may act as a sensitive indicator for anthropogenic climate change. Existing observational and modeling studies have shown the middle atmosphere and the MLT is cooling and contracting because of increasing greenhouse gas emissions. However, trend analyses are ...
    • Testing the hypothesis of the influence of neutral turbulence on the deduction of ambipolar diffusivities from meteor trail expansion 

      Hall, Chris; Aso, T.; Tsutsumi, M.; Nozawa, S.; Manson, A.H.; Meek, C.E. (Journal article; Peer reviewed; Tidsskriftartikkel, 2005-03-30)
      Fading times of radar echoes from underdense meteor trails in the upper mesosphere/lower thermosphere are commonly used to determine ambipolar diffusivities and hence ambient temperature. Diffusivities are generally expected to increase exponentially with height through the region from which the meteor trail echoes are obtained, viz., typically 70-110km altitude for a ~30-MHz radar. In practice, ...