This book describes how to predict and forecast the state of planet Earth’s ionosphere under quiet and disturbed conditions in terms of dynamical processes in the weakly ionized plasma media of the upper atmosphere and their relation to available modern measurements and modelling techniques. It explains the close relationship between the state of the media and the radio wave propagation conditions via this media. The prediction and forecasting algorithms, methods and models are oriented towards providing a practical approach to ionospherically dependent systems design and engineering. Proper understanding of the ionosphere is of fundamental practical importance because it is an essential part of telecommunication and navigation systems that use the ionosphere to function or would function much better in its nonappearance on the Earth and on any planet with an atmosphere.

A world-wide model of ionospheric irregularities giving rise to scintillations was developed by Fremouw and Rino of Stanford Research Institute. This model takes into consideration diurnal, seasonal, and solar variations. Also considered is the dependence on geomagnetic latitude, frequency, and the geometry between the transmitter and the receiver. This model was used to make computations appropriate for the GOES system, assuming the satellite to be parked on 100°W longitude. Calculations were made at 400 MHz for sunspot numbers 30, 100, and 200, coo responding to low, medium, and high solar activity; for solstice and equinoctial periods; and for several times of the day. The results are presented as contour maps of the earth as viewed from GOES. The results show that for low solar activity periods serious scintillations will occur only within about ± 10 degrees of the geomagnetic equator. During moderately active periods stations located in the vicinity of the auroral zones will also be affected. The worst case condition occurs for sunspot number 200, during the equinox, and at midnight , on the longitude of the geostationary satellite. In general, the mid-latitude regions are relatively free from scintillations. These results should be useful in determining the positioning and programming of the data readout of the numerous surface-based stations to be used in connection with the data collection and relay subsystem.