水平非均匀性蒸发波导诊断及其对雷达探测的影响

蒸发波导是发生在海气边界层的一种异常折射现象,因为其分布广、发生概率大,所以被认为是对海上电子装备影响最为显著的波导类型。然而由于其形成机制复杂,且在近岸地区存在水平不均匀性,使得目前非均匀蒸发波导的诊断及其应用还未能落实到实际工作中。针对这一现状,首先利用G L Geernaert的方法修正了Monin-Obukhov相似理论,将其扩展到海洋大气表面边界层不均匀条件下;其次在Babin模式的基础上引入张强普适函数的非线性修正因子与阵性风速,从而将蒸发波导诊断模式的适用范围拓展到近海沿岸地区和甚低风速条件下。并在此基础上研究了蒸发波导水平非均匀性对雷达探测的影响,得到了水平非均匀蒸发波导能够改变均匀波导环境下雷达的探测距离及其盲区的分布。

Diagnosis of the Horizontal Inhomogeneity Evaporation Duct and Its Influence on the Radar Detection

Evaporation duct is a kind of anomalous refraction phenomenon in the marine boundary layer. Because of its wide distribution and high probability of the occurrence, it is considered to be the most significant type of the duct, which has an important effect on the electronic equipment on the sea. However, due to the complex formation mechanism and the horizontal inhomogeneity in the offshore zone, the diagnosis and the application of the inhomogeneous evaporation duct have not been implemented in practical work. For the present situation, firstly we modified the Monin-Obukhov similarity theory by using the method of G.L.Geernaert (2002), and extended it to the conditions of the inhomogeneous atmosphere in the ocean surface layer. Secondly, based on Babin model, the nonlinear correction factor proposed by Zhang Qiang and Hu Yin-qiao and gust velocity item are introduced, so that the field of the application for the evaporation duct diagnosis model can be extended to the coastal areas and the very low wind speed. Thirdly, the influence of the horizontal inhomogeneous evaporation duct on the radar detection is studied, and the result shows that the horizontal inhomogeneous evaporation duct can change the detection distance and the distribution of the shadow zone for the radar.