HF COMMUNICATION EFFECTS: PROPAGATION IN THE HIGH-LATITUDE IONOSPHERE.
STANFORD RESEARCH INST MENLO PARK CALIF
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The interrelationships of particular high-latitude phenomena--E sub s, magnetic storms, complex ray paths, and field-aligned ionization--and HF oblique sounder observations from five paths for one year are analyzed in this report. Magnetic field deviations produced during magnetic storms were found to be highly correlated with ionospheric variations that occurred one to three hours after the magnetic variations. Equations relating the magnetic field variations to the ionospheric variations are developed in this report with generally favorable results. Prediction of E sub s oblique mode occurrences and MOFs from vertical sounder data is also presented in this report. The sounder data was used to plot maps of f sub o E sub s and percent occurrence. Good agreement is found between the observed oblique mode statistics on four paths and those predicted from the maps. Ray-tracing techniques were used to simulate the observed oblique ray paths from vertical -incidence sounder data taken along the oblique paths. It was found that ray-tracing techniques were remarkably accurate, considering the drastic variations in ionospheric parameters along the path. Ray-tracing techniques for modes using field-aligned ionization are also presented in this report. Time delays derived by these techniques fit remarkably well with statistics for the observed scatter-modes on two paths. Author
- Atmospheric Physics
- Radiofrequency Wave Propagation