Remote sensing of natural and artificial variations in the Earth-ionosphere cavity via very low frequency

In this article we present results from very low frequency (VLF) observations of transient and intermittent phenomena in the Earth-ionosphere waveguide. The scientific objectives are remote localisation and characterisation of short time disturbances. The VLF amplitude and phase variations aid to physically investigate the atmospheric media from the Earth's surface up to the lower ionosphere (~ 70-90 km, D- and E-region) which is part of propagation channels for satellite communications and navigational applications. We consider two common types of anomalies in the waveguide, these events are associated with (i) solar flares and (ii) geomagnetic storms. We conclude that with a continuous operating VLF receiver network a service for lower atmospheric channel monitoring / characterisation can be established.