ANALYSIS OF IONOSPHERIC DATA
Semi-annual technical rept. no. 4, 1 Oct 1967-31 Mar 1968
IIT RESEARCH INST CHICAGO IL
Pagination or Media Count:
The average and short term fluctuations in apparent doppler frequency imposed upon three high frequency short-hop propagation paths are described. The average variation in doppler frequency during development of the reflecting region at dawn for both geomagnetically disturbed and quiet conditions can be characterized by an exponentially decaying positive doppler signal. The small scale doppler frequency fluctuations are analyzed by power spectral analysis techniques. It is shown that the that the power spectra usually have a constant spectral intensity at high frequencies e.g. a white spectrum, and a slightly increasing spectral intensity at lower frequencies e.g. a pink spectrum. The power contained in the white portion of the spectrum is shown to be correlated with the geomagnetic activity index. The average changes in doppler frequency for quiet and disturbed daytime periods are related to the determination of the level of range and x-ray yield at which nuclear bursts in space may be detected against the natural background. Also, the natural fluctuation level of the hf doppler signals is related to the level of x-ray yield and range at which nuclear burst effects can be distinguished from the natural doppler noise level of an hf detection system.
- Atmospheric Physics
- Radiofrequency Wave Propagation