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Radio Science

Ionospheric Absorption of Radio Waves During Sunrise and Sunset Hours


  • R. K. Rai


The variation of nondeviative absorption of radio waves in the ionosphere with solar zenith angle has been studied at different spot frequencies. The experimental results suggest that the theoretical expression for the nondeviative absorption in the morning and evening hours should contain a constant absorption term along with the term dependent on the solar zenith angle. In the present communication it has been shown that the constant absorption term is present throughout the day, but its effect is not apparent toward noon hours, and at these hours the experimentally observed values of absorption at a fixed frequency appear to be a function of solar zenith angle only. The probable origin of the constant absorption term has been discussed.

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