基于微波链路的路径雨强反演方法及实验研究

从大气气体吸收衰减模型出发, 基于微波雨衰特性和雨滴谱统计资料建立了微波链路降雨有效衰减的修正模型和视距微波链路的降雨反演模型. 设计并搭建一条视距微波链路测雨实验系统, 利用降雨反演模型反演了路径平均降雨强度, 并与雨滴谱仪进行了同步对比. 观测结果表明, 视距微波链路降雨反演模型的反演雨强与雨滴谱仪测量结果的相关系数大多高于0.6, 最高可达0.9647; 累积降雨量的绝对误差大多在0.5 mm以内, 最小偏差仅有0.0827 mm; 相对偏差大部分在15%以内, 最小相对误差为3.3415%. 实验结果验证了微波链路反演降雨的有效性和准确性.

Research on the method and experiment of path rainfall intensity inversion using a microwave link

Accurate measurement of rainfall with high spatial and temporal resolution have important significance in meteorology, hydrology, agriculture, environment, flood warning and weather forecasting, etc. Based on the rain-induced power-law attenuation, an inversion method of the path rainfall intensity is proposed by using a microwave link. Starting from the atmospheric gas absorption attenuation model, a correction model of rainfall effective attenuation and a rainfall inversion model for line-of-sight microwave links are proposed, based on the microwave rain attenuation characteristics and raindrop size distribution statistics. A line-of-sight microwave link is designed and used to measure the rainfall, and the path average rain rate is inversed by means of rainfall inversion model, which is compared with a disdrometer. Results show that the correlation coefficient of rain rate inversed by microwave link with that of disdrometer is higher than 0.6 mostly, and the maximum value is 0.9647; the error of the accumulated rain amount is less than 0.5 mm, and the minimum value is 0.0827 mm; the relative error of the accumulated rain amount is less than 15%, the minimum value is 3.3415%. Experiments confirm the feasibility and accuracy of rainfall inversion obtained using a microwave link.