The two figures in each map set show areas of potential communications problems on links from the ground to Inmarsat (left-hand map) and to Norsat-C (right-hand map). The primary location of interest is indicated by a solid circle. The color shading indicates the expected level of the intensity-scintillation index, S4. Areas of green shading should experience no scintillation or very low levels, areas of yellow shading may experience moderate levels of scintillation, and areas of red shading may experience high levels of scintillation.
The scintillation estimates are calculated using the SCINTMOD scintillation-effects tool which is based on the WBMOD ionospheric scintillation model. These codes use a climatological model of the ionospheric irregularities and are not based on analysis of observed scintillation conditions but rather on specifications of the geophysical environment. As such, these maps show regions where scintillation is likely given current and predicted geogphysical conditions.
A note on the mapping used: The S4 estimates along a particular ray path has been mapped to the latitude and longitude of the ground end of the ray path.
Copyright © 2000 by Northwest Research Associates, Inc.