Articles | Volume 13, issue 4
Ann. Geophys., 13, 450–453, 1995
https://doi.org/10.1007/s00585-995-0450-z
Ann. Geophys., 13, 450–453, 1995
https://doi.org/10.1007/s00585-995-0450-z

  30 Apr 1995

30 Apr 1995

Polar lacuna on ionograms. E- or F-region processes?

P. Stauning P. Stauning

Abstract. Lacuna on ionograms indicate conditions where the usual ionospheric reflections of vertically propagating radio waves transmitted from and subsequently received by an ionosonde are missing over a range of frequencies. Reflections from the lowermost E-region should still be observable contrary to the more usual cases where absorption processes in the underlying D-region removes the low-frequency part of the ionospheric reflections appearing in ionograms. It is emphasized below that lacuna cases related to E-region processes should be distinguished from lacunae related to processes in the F1 and F2 regions. This distinction appears to have been neglected in a recent paper.