Tromsø geofysiske observatorium: Nye registreringer

Viser treff 41-42 av 42

    • On the possibility of ion-drag to induce dynamic instability in the lower thermosphere neutral gas 

      Hall, Chris (Journal article; Tidsskriftartikkel; Peer reviewed, 2000)
      Strong wind shears may result in dynamic instability, often characterised by the Richardson number lying between zero and 0.25. The extent to which electric-field driven ion flow may induce such neutral wind shears is examined. Further, it is proposed that, in the ionosphere, it is possible for electric fields to drive ion winds such that the collisionally induced neutral air response may be comparable ...

    • Isolated lower mesospheric echoes seen by medium frequency radar at 70º N, 19º E 

      Hall, Chris; Manson, A.H.; Meek, C.E.; Nozawa, S. (Journal article; Peer reviewed; Tidsskriftartikkel, 2006-11-23)
      We have noted sporadic instances of strong isolated reflections of medium frequency (MF) radar waves from the mesosphere from as low as 50 km altitude and have devised a set of criteria for isolating these apparently anomalous echoes from those normally occurring from progressive partial reflections in the D-region. The object of this study is to map the occurrences of such echoes facilitating ...