![]() ![]() ![]() Qie X S, L D R, Chen H B, Wang P C, Duan S, Zhang W X 2008 Chin. Liang H H, Xu B X, Liu L P, Ge R S 2005 Adv. L D R, Wang P C, Qiu J H, Tao S Y 2003 Chin. Rain-induced microwave attenuation measurements / In addition, the experimental result reflects that rainfall intensity retrieved method based on nonspherical raindrop model has advantages over the method based on spherical raindrop model. The experimental results validate the feasibility and accuracy of rainfall inversion method proposed in this paper. The results show that the correlation coefficient of rain rate inversed by microwave link and that of disdrometer are both higher than 0.6 mostly, and the maximum value is 0.96 the error of accumulated rain amount is less than 2.47 mm, the minimum value is 0.28 mm the relative error of accumulated rain amount is less than 1.84%, the minimum value is 0.44%. Besides, we design a line-of-sight microwave experimental system for measuring the rainfall, and the path average rain rate is inversed by rainfall inversion model, which is compared with an OTT disdrometer. Meanwhile, we analyze the variations of parameters of rain-induced model under the condition of different temperatures. In this paper, we propose 15-20 GHz inversion model of path-average rainfall intensity based on nonspherical rain-induced model by using Levenberg-Marquardt optimization algorithm. The correction model of rainfall effective attenuation and rainfall inversion model of line-of-sight microwave links are proposed, based on the microwave rain attenuation characteristics and raindrop size distribution statistics. On the basis of scattering theory and by utilizing the Gamma raindrop size drop, we use the extended boundary condition method to calculate the characteristics of microwave attenuation for Pruppacher-Beard raindrop shape model. In this paper, we use the characteristics of an atmospheric attenuation model to eliminate the influence of non-rainfall-caused attenuation on the process of rainfall inversion. Therefore, based on extended boundary condition method and Gamma raindrop size distribution, an inversion method of the path rainfall intensity by using a microwave link rain-induced attenuation is proposed in order to improve the accuracy of rainfall measurement by microwave rain-induced attenuation. Further, obtaining parameters that comply with all rainfall events for the rainfall attenuation model is a challenge, often leading to an overestimation of the rainfall intensity. However, the inversion of a single-frequency link is based on the assumption of rainfall attenuation under a certain frequency condition. The use of attenuated information about microwave propagation in rainfall areas to acquire surface precipitation intensity has been shown to be a practical approach to measuring rainfall in recent years. It is important to measure rainfall accurately with high spatial and temporal resolution in meteorology, hydrology, agriculture industry, environment conservation, flood warning and weather forecasting. ![]()
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