Main Pages: [ NWRA Space Weather Services Home | SpaWx Indices Home | Scintillation Home | Scintillation Services Home | ]
Graphics: [ F10 | Ap | F10/Ap Forecasts | SSNe | SSN Comparison | 24hr SSNe | Kp+GOES+DSCOVR | Qe+GOES+DSCOVR ]
Listings/Reports: [ Indices Table | Events | RSGA | SGAS | SRS | Predict ]

Comparison of Sunspot-Number Indices


This plot illustrates the differences between the "real" sunspot number (SSN), which is calculated from optical observations of the sun, a sunspot number derived from the 10.7cm solar radio flux (SSNf), and a sunspot number derived from fitting an ionospheric model to ionospheric measurements. All of these indices are used as inputs to models of the ionosphere for use in communications-performance predictions - this plot shows that they don't always agree as to what the SSN should be in that particular context.

Note: The F10.7-derived SSN (SSNf) is calculated from the 10.7cm solar radio flux (the Penticton Radio Observatory noon value) using the following relationship:

F10.7 = 63.74 + 0.727*SSNf + 0.000895*SSNf**2

How good is this relationship?

NWRA Space Weather Links

[ Space Weather Home Page | Scintillation Home Page ]

[ Home | About NWRA | Staff | Research Areas | Products ]

How to contact NWRA

Copyright © 1996-2020 NorthWest Research Associates, Inc.  All rights reserved.