E-region echoes

The E region is the atmospheric/ionospheric region between 90 and 150 km and forms part of what is known the lower thermosphere. The lower thermosphere influences the mesosphere and even the upper stratosphere. Some physical processes of general relevance appear specifically pronounced here, e. g., wave mixing and generation of secondary gravity waves. This region is dynamically coupled to the mesosphere and lower atmospheric regions by gravity waves, tides, and planetary waves which propagate upward from below and often dissipate in the 80 to 150-km region. To explore this region with IAP radars, we make use of the following E region echoes: (a) specular meteor echoes with small meteor radars, (b) incoherent scatter echoes with MAARSY when electron densities are high enough, (c) nonspecular meteor trail echoes with MAARSY and small meteor radars, that are believe to be associated to charged meteor dust, and (d) from E region field-aligned irregularities with radars pointing perpendicular to the magnetic field lines. The latter will be studied with a soon-to-be deployed coherent radar imaging system at Juliusruh (JULIE). From these echoes, besides studying the physics that explain them, we plan to diagnose the atmosphere/ionosphere (e.g., neutral winds, electric fields, temperatures, neutral density, etc.)

Publications

  • M. Rapp, L. Leitert, R. Latteck, M. Zecha, P. Hoffmann, J. Höffner, U.-P. Hoppe, C. La Hoz und E. V. Thrane, Localized mesosphere-stratosphere-troposphere radar echoes from the E-region at 69° N: Properties and physical mechanism, J. Geophys. Res., 116, A02320, doi:10.1029/2010JA016167, 2011
  • Hysell, D. L., E. Nossa, M. F. Larsen, J. Munro, M. P. Sulzer, and S. A. Gonza´lez , Sporadic E layer observations over Arecibo using coherent and incoherent scatter radar: Assessing dynamic stability in the lower thermosphere, J. Geophys. Res., 114, A12303, doi:10.1029/2009JA014403, 2009
  • Chau, J. L. and D. L. Hysell, High altitude large-scale plasma waves in the equatorial electrojet at twilight, Ann. Geophys., 22, 4071-4076, doi:10.5194/angeo-22-4071-2004, 2004
  • Hysell, D. L. and J. L. Chau, Imaging radar observations and nonlocal theory of large–scale waves in the equatorial electrojet, Ann. Geophys., 20, 1167-1179, doi:10.5194/angeo-20-1167-2002, 2002
  • Rüster, R. and Schlegel, K.: Non-magnetic aspect sensitive auroral echoes from the lower E region observed at 50 MHz, Ann. Geophys., 17, 1284-1292, doi:10.1007/s00585-999-1284-x, 1999

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