Ionospheric Monitoring and Solar Flare/CME Detection

The ionosphere is high outer layer of the Earth's atmosphere, charged (ionised) by solar radiation. This charging allows radio signals to bounce off the ionosphere and propagate over long distance. The ionosphere is also sensitive to the impact of space weather, and when this happens we should see changes in the signal strength of radio transmissions. There are also signature markers for solar flare x-ray events, which are usually correlated with coronal mass ejections (CMEs).

At Dunedin Aurora we monitor:

• The amplitude of the signal from an Australia VLF naval transmitter (Station NWC in Western Australia). VLF radio is especially senstitive to change in the ionosphere.
• The signal to noise ratio of GPS satellite transmission to a common GPS module.

VLF Monitor - Last 24 Hours

The VLF antenna is a wire loop with approx 50 turns of wire. The signal is passed through a "SuperSID" filter and processed with Spectrum Lab software and custom software. Reception of long distance stations shows a diurnal variation in signal strength. This signal can be altered by space weather and x-rays generated by solar flares.

S4 Median Values - Last 24 Hours

Scintillation Monitor - last 72 hours

The GPS signal is recieved with a Sparkfun "SAM" GPS module and processed with custom software. The satellite signal can be affected by the uneven make-up of the ionosphere, causing it to scintillate (Similar to how the turbulent atmosphere causes stars to twinkle). This scintillation is worse during geomagnetic storms and should show as a surge. The S4 index measures the amplitude of this scintillation.