双/多基地天气雷达探测小椭球降水粒子的侧向散射能力

首先给出小椭球粒子侧向和后向散射截面的表达式,将其中相关参数用双基地雷达坐标系中的量表示,在定义小椭球粒子侧向散射能力后,分别推导出发射水平与垂直偏振波条件下估算侧向散射能力的算式,并通过仿真计算,获得各高度上的侧向散射能力和分布情况.得出的主要结果为:(1)发射水平偏振波时,在低高度的等高面上,当离开基线垂直向上或向下距离增加时,侧向散射能力先逐渐变小到最小值后,再逐渐增大.在基线左、右的延线上也基本呈这种分布,仅在主站与子站的垂直方向上存在侧向散射能力的最低区域.随着等高面高度升高,侧向散射能力分布情况基本相似,仅子站上下的弱侧向散射值有所提高.(2)发射垂直偏振波时,在低高度水平面上无论被探测的扁旋转椭球粒子处在该平面上(除主站与子站张培昌等:双/多基地天气雷达探测小椭球降水粒子的侧向散射能力.

Study of the side-scattering capability of bistatic/multistatic weather radar system detecting small spheroid raindrops

Expressions for the side-scattering cross-section and back-scattering cross-section of a small spheroid particle are given and then using the parameters in the bistatic weather radar system expresses the relevant parameters in this expressions.to defining the side-scattering capability of the small spheroid particle,the equations of side-scattering capability are derived for the cases in which the polarization of the transmitted radar wave is horizontal and vertical respectively.The side-scattcrmg capability distribution maps at the different altitudes can be obtained from the simulative calculation,and by analysis of these maps,we can conclude some referenced results.The main results include that (1)If the active radar emits horizontal polarization waves,the side-scattering capability decreases gradually to a minimum,and then increases gradually, with the increasing distance between the particle projection and the baseline at lower altitude.This characteristic exists at the extensions of the baseline on both sides, as well.As the altitude increases, the feature on the side-scattering capability is similar to that at lower altitude.But the capability has a slight strengthening around the passive radar.(2) If the active radar emits vertical polarization waves, the side-scattering capability of the whole lower altitude plane is always at a maximum besides the positions of two radarn.As the altitude increases, weaker scattering areas appear around the active radar and the passive radar, and the size of the areas is increasing with the altitude.