Turbulent Mixing Theory Applied to Radio Scattering

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Abstract
Obukhoff's statistical theory of turbulent mixing is proposed as a replacement for the heuristic theories of Gallet and Villars‐Weisskopf, and is applied to the problem of the scattering of radio waves by refractive index fluctuations. In the case of ionospheric scattering, order‐of‐magnitude agreement with the observed scattered power is obtained if the refractive index fluctuations are attributed to electron density fluctuations produced by turbulent mixing in the lower edge of the E layer. In the case of tropospheric scattering, it appears that order‐of‐magnitude agreement with the observed scattered power can be obtained, except during the summer months, by attributing the refractive index fluctuations to temperature fluctuations. During the summer months and at low scattering heights, humidity and its fluctuations are expected to play a prominent role. Experimental and theoretical evidence is cited in favor of perennial fractional‐degree temperature fluctuations in the troposphere. A comparison of the Obukhoff, Villars‐Weisskopf, and Booker‐Gordon models is given, and it is found that the Obukhoff model predicts the most scattered power.