• 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, ...
    • Tidal signatures in mesospheric turbulence 

      Nozawa, S.; Hall, Chris; Manson, A.H.; Meek, C.E. (Journal article; Peer reviewed; Tidsskriftartikkel, 2006)
      We search for the presence of tidal signatures in high latitude mesospheric turbulence as parameterized by turbulent energy dissipation rate estimated using a medium frequency radar, quantifying our findings with the aid of correlation analyses. A diurnal periodicity is not particularly evident during the winter and spring months but is a striking feature of the summer mesopause. While semidiurnal ...
    • Tropopause height at 78 degrees N 16 degrees E: average seasonal variation 2007-2010 

      Hall, Chris; Hansen, Georg Heinrich; Sigernes, F; Kuyeng, Karim (Journal article; Tidsskriftartikkel; Peer reviewed, 2011)
      We present a seasonal climatology of tropopause altitude for 78° N 16° E derived from observations 2007–2010 by the SOUSY VHF radar on Svalbard. The spring minimum occurs one month later than that of surface air temperature and instead coincides with the maximum in ozone column density. This confirms similar studies based on radiosonde measurements in the arctic and demonstrates downward control by ...
    • Tropopause height at 78°N 16°E: average seasonal variation 2007-2010 

      Hall, Chris; Hansen, Georg; Sigernes, Fred; Kuyeng, Karim (Journal article; Tidsskriftartikkel; Peer reviewed, 2011)
      We present a seasonal climatology of tropopause altitude for 78° N 16° E derived from observations 2007–2010 by the SOUSY VHF radar on Svalbard. The spring minimum occurs one month later than that of surface air temperature and instead coincides with the maximum in ozone column density. This confirms similar studies based on radiosonde measurements in the arctic and demonstrates downward control by ...
    • Vertical and interhemispheric links in the stratosphere-mesosphere as revealed by the day-to-day variability of Aura-MLS temperature data 

      Hall, Chris; Xu, X; Manson, A.H.; Meek, Chris; Chshyolkova, Tatyana; Drummond, J. R.; Riggin, D.; Hibbins, RE (Journal article; Tidsskriftartikkel; Peer reviewed, 2009)