基于雷达海杂波的区域性非均匀蒸发波导反演方法

由于不同海域上空气象条件的不同, 海上蒸发波导在大尺度海面上空发生时通常是区域性非均匀的, 这一特性使得该环境中的电波传播特性相对于水平均匀的蒸发波导环境情况而明显不同, 因此, 进行区域性非均匀的蒸发波导探测反演对正确预测电波传播特性及提高雷达系统的工作性能具有重要的意义. 考虑到实际应用中蒸发波导信息获取手段的多样性, 将中尺度数值气象模式MM5预报的区域性蒸发波导修正折射率剖面作为先验信息, 提出了一种含该先验信息的区域性非均匀蒸发波导的雷达海杂波后验概率估计模型. 该模型使用主分量分析法对蒸发波导的水平非均匀性进行参数化建模, 然后通过贝叶斯理论将修正折射率剖面参数的先验概率分布、后验概率分布和似然函数联系起来, 利用雷达海杂波实现蒸发波导剖面参数的最大后验概率估计反演. 通过我国东海海域的实际区域性非均匀蒸发波导反演测试, 表明该模型能够以更高的精度实现区域性非均匀蒸发波导的反演.

Inversion of regional range-dependent evaporation duct from radar sea clutter

Because the weather conditions in different sea areas are different, the evaporation duct occurring over a large sea surface is normally regional and range-dependent. This property results in the fact that the radio wave propagation within the environment of this type is distinct from that within the range-independent evaporation duct environment. Therefore, it is meaningful to perform the regional range-dependent evaporation duct inversion for accurately predicting radio wave propagation and improving radar performance. From among the variety of ways of detecting evaporation duct in practical application, we adopt the regional modified refractivity profile of evaporation duct predicted by the mesoscale numerical weather model MM5 as the prior information, and propose a posterior probability estimation model of the regional range-dependent evaporation duct on the basis of the radar sea clutter power. First, in this model we use the principal component analysis method to model the range-dependent property of evaporation duct, and on this basis, establish the inversion procedure of the range-dependent evaporation duct by using the radar sea clutter. Then, we obtain the relationship among prior probability distribution, posterior probability distribution, and likelihood function of the parameters of the modified refractivity profile by using the Bayesian theory, and finally realize the maximum posterior probability estimation of the evaporation duct parameters. By estimating the real regional range-dependent evaporation duct over East China Sea, it is indicated that the proposed model can perform the inversion of regional range-dependent evaporation duct with a higher precision.