Global ionospheric -layer height monitoring

¹ Institut für Meteorologie und Geophysik - Feldberg straße 47 D-60323 Frankfurt am Main, Germany
² STAR Laboratory - Stanford University, Stanford, CA 94305, USA
³ Max-Planck Institut für Aeronomie - Max-Planck Straße 2 D-37191 Katlenburg-Lindau, Germany

Received: 15 February 2002
Accepted: 27 May 2002

Abstract

A global two-scale height ionospheric conductivity profile is inferred from the mean electromagnetic-wave propagation velocities of seven Earth-ionosphere cavity resonances in the frequency range . The time-varying reflection height for the electromagneticwaves is monitored on a diurnal basis. This D-layer height exhibits an increase at solar quiet conditions associated with decreased ionisation at mesospheric altitudes from solar short-wave radiation during the solar cycle and the solar rotation period. It is concluded that it is possible to monitor the global ionospheric D-layer heightvariability with naturally occurring electromagnetic waves in the atmosphere. A small network of magnetometers may detect and locate large-scale remote areas of mesospheric conductivity profile perturbations from short-lived extraterrestrial ionisation sources in the South Atlantic geomagnetic field anomaly, which are an appreciated hazard to spacecraft operation.