Effect of charges carried by atmospheric particles on radar power ratio

Abstract. The ratio of the receiving power to the transmitting power (RPR) of a well-designed radar system is determined by the absorption and scattering of materials coming into contact with radar waves along the propagating path of the radar wave. In atmospheric detection by a radar system, the RPR is mainly determined by the absorption and scattering of atmospheric particles. Particle properties, such as the charge carried by particles, will affect the RPR. Particle charging is common in a particle system. The present study investigated the effect of charges carried by atmospheric particles on the RPR. It was found that charges carried by particles can increase the RPR, and the increment is related to the charges, particle size parameter, radar emission frequency, and corresponding refractive index of the particles. As the emission frequency of the radar increases, the effect of the charges on the RPR decreases, and especially, the effect of charges on the RPR can be ignored for lidar used to detect sand particles. The number density of particles based on the RPR without considering charges carried by sand particles will be overestimated relative to that when considering charges carried by sand particles. The overestimation increases with the surface charge density, for the same type of radar.