Sudden Ionic Disturbance Monitors

[Yowbarb]

http://solar-center.stanford.edu/SID/sidmonitor/

The SID Monitor

[Yowbarb]

http://en.wikipedia.org/wiki/Sudden_ionospheric_disturbance

A sudden ionospheric disturbance (SID) is an abnormally high ionization/plasma density in the D region of the ionosphere caused by a solar flare. The SID results in a sudden increase in radio-wave absorption that is most severe in the upper medium frequency (MF) and lower high frequency (HF) ranges (adapted from Federal Standard 1037C and from MIL-STD-188), and as a result often interrupts or interferes with telecommunications systems.