【摘要】 本文从湍流大气对声波散射方程出发,推导出静止大气和有水平运动两种情况下,有限接收面积上的平均准后向散射截面公式。从而分析了影响平均准后向散射截面的因子,同时还计算讨论了不同天线口径、风速和值的平均准后向散射截面。 计算结果表明:在一般情况下,边界层内用声雷达测得的温度结构系数[C_T~2(θ)]要比理论上纯后向温度结构系数[C_T~2(180°)]大些;C_T~2(θ)与C_T~2(180°)比值以及C_T~2(θ)随高度的变化都与天线口径、风速分布和m值等密切相关。因此对用不同声雷达在不同大气条件作对比测量,得到某些不一致的现象,可给予一定的解释。更多还原

【Abstract】 Based on the scattering equation of sound wave in turbulent medium, a formula for the mean quasi-backscattering section on a finite receiving area under static condition and condition with horizontal velocity has been derived. Factors affecting the mean quasi-backscattering section are analysed, and the mean quasi-backscattering sections for va-rious antenna diameters, wind velocities and are calculated,The calculated results show that in atmospheric boundary layer the temperaturestructure coefficient [ c2t(θ) ] measured by acoustic radar is greater than pure theoretical one [C2T(180°)]. The ratio [C2T(θ)/C2T(180°)] and variation of C2T(θ) with altitude are related to antenna diameter, profile of wind velocity and m value. Thus, some differences between the measurements obtained by different acoustic radars under different atmospheric conditions may be explained by these calculated results.更多还原