Preliminary Climatology of UHF Scintillation over the South American Equatorial Anomaly at Solar Minimum
RADEX INC BEDFORD MA
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We have deployed two 250 MHz radio receivers in South America one at the magnetic equator and another near the peak of the anomaly crest. These stations listen continuously to both an eastern and western communications satellite. The unique deployment allows for two measurements at common magnetic latitudes and one along a common field line. Data has been gathered for more than a year and statistical studies have been performed, which are compared to the popular Wide Band Scintillation Model WBMOD. The preliminary results presented here show a persistence of scintillation several hours later into the evening than predicted by the model. The seasonal variation of the model matches the measurements quite well, however. The results elucidate both the strengths and weaknesses of our predictive capability. In addition to these statistical measures, we present results on east west asymmetry in scintillation from the two stations. The equatorial station shows little asymmetry while the southern station exhibits a significantly stronger scintillation to the east than to the west. The asymmetry appears to have a seasonal dependence. The origin of this phenomenon is unclear, but a few possibilities are suggested. Simultaneous data from the common field line links are also compared. A brief presentation is made of the PL-SCINDA scintillation warning system, which uses the data from these stations for now casting and scintillation forecasts. Work in progress on the deployment and utilization of GPS units in this effort is also discussed.
- Radiofrequency Wave Propagation