Depolarization of microwave by sand-dust particles in atmospheric turbulence

Abstract

In this paper, the depolarization effect of the two-orthogonal polarized microwaves (MWs) by spheroid sand-dust particles in atmospheric turbulence is studied based on T-matrix theory. The results indicate that the depolarization effect by spheroidal particles can be weakened in turbulence, namely, as the turbulent intensity increases, the cross-polarization discrimination (XPD) of the MWs increases. In the case of the strong turbulence with turbulent dissipation rate of 1000 cm2s−3, the XPD of MWs with frequency of 10 GHz propagating through sand/dust system can be strengthened by 28% when the visibility is 10 m, and by 10% when the visibility is 1 km. A function of the relationship between XPD and co-polarization attenuation (CPA) for the circularly polarized MWs propagating in the charged dust/sand particle system is also presented, which is not dependent on the turbulent intensity but on the charges carried by particles. XPD of 3 GHz MWs by the dust/sand particle system with particles carried surface charges of -60 µC/m2 is 75% higher than the one by the corresponding neutral system given CPA of 0.5 dB, while 5 times higher than that by the corresponding neutral particles given CPA of 1 dB. However, XPD by dust/sand system compared to the one by rain given the same CPA, the former is much lower than the later.