The figures on these two pages show areas of potential scintillation from ionospheric irregularities on paths from a receiver at the location indicated by a star to a satellite at an altitude of 1000 km. The colored region specifies the level of ionospheric scintillation on a one-way path from the satellite to the receiver down to an elevation angle of 2 degrees. The environmental conditions chosen for these cases (SSN=120, Kp=7-, and local midnight) can be considered reasonable worst-case scenarios.
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.
The parameter plotted, the S4 index, is the normalized RMS variation of signal power. We are using the 90th percentile occurrence statistics from the WBMOD climatology for these plots. Thus, we expect that the S4 levels shown in these figures to be exceeded only 10% of the time for the specificed geophysical conditions. The color shading indicates the expected level of scintillation. 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.Citations for models documentation.
A note on mapping: All of the information shown on these figures have been mapped to the latitude and longitude of the satellite end of the ray path on which they occur.
Copyright © 1998-2000 by Northwest Research Associates, Inc.