S4 Index Explained

The

S _{4} Index is a standard index used to measure ionospheric disturbances. It is defined as the ratio of the standard deviation of signal intensity to the average signal intensity.^[1]

Real Time data

This parameter is displayed in real time by many institutions:

• at Arecibo Observatory
• at Cornell University
• at INPE, in Brasil

Notes and References

1. Book: Basu . Santimay . Basu . Sunanda . Scintillation technique for probing Ionospheric irregularities . 128.