Interference of tidal and gravity waves in the ionosphere and an associated sporadic E-layer

  • Nygrén T
  • Lanchester B
  • Huuskonen A
 et al. 
  • 4


    Mendeley users who have this article in their library.
  • 20


    Citations of this article.


Observations made on 10 July 1987 with the EISCAT UHF radar are presented. The F-region measurements of both electron density and field-aligned ion velocity show that an upward propagating gravity wave with a period of about 1 h is present. The origin of the gravity wave is probably auroral. The E-region ion velocities show a tidal wave and both upward and downward propagating gravity waves. The gravity waves have three dominant periods with a possible harmonic relationship and similar vertical wavelengths. These waves are either reflected at a single reflection level, ducted between two levels, or they are generated in a non-linear interaction between gravity and tidal waves. The E-region electron density is dominated by particle precipitation. After a short burst of more intense precipitation, a sporadic E-layer forms at 105km and then disappears 40min later. Within this time, the layer rises and falls by a few kilometres, following closely the motion of a convergent null in the velocity profile. We suggest that the formation and destruction of this layer is controlled by both the precipitation, which indirectly provides a source of metal ions through charge exchange, and the superposition of gravity waves and the tidal wave. © 1990.

Get free article suggestions today

Mendeley saves you time finding and organizing research

Sign up here
Already have an account ?Sign in

Find this document


  • T. Nygrén

  • B. S. Lanchester

  • A. Huuskonen

  • L. Jalonen

  • T. Turunen

  • H. Rishbeth

Cite this document

Choose a citation style from the tabs below

Save time finding and organizing research with Mendeley

Sign up for free