On detecting reflections in presence of scattering from amplitude statistics with application to D region partial reflections

In many radar experiments which use transmission or scattering of radio waves through a random medium, the received signal is modeled as a reflected sine wave of amplitude A in a scattered narrow-band Gaussian random process of variance 2σ². In this model the received signal amplitude has a Rice family of distribution characterized by a parameter α = A/σ. It is shown that amplitude statistics cannot be used to discriminate weak reflections from scattering (α < 0.5). Behavior of mean, skewness, and kurtosis of the normalized signal amplitude is examined for a constant and an intermittent reflected component. It is shown that intermittency has a strong effect on these. Applications to a D region partial-reflection experiment at Tromsø are briefly discussed. It is shown that, at least in some simple cases, enhanced reflections arise from the top and bottom parts of turbulent layers.