卷云大气条件下目标与背景对比度模拟分析

Simulation Analysis of Target and Background Contrast in Condition of Cirrus Atmosphere

使用通用大气辐射传输软件模拟计算了卷云大气条件下强吸收波段的反射率,分析了卷云粒子形状和有效尺度、光学厚度和卷云高度对大气顶反射率和背景辐射的影响。建立了高温气体目标的辐射强度计算模型,并通过模拟获取了目标辐射在卷云大气中传输至大气顶的光谱辐射特性。计算了大气顶的目标背景对比度,并讨论了卷云特性参数和目标高度对目标背景对比度的影响。结果表明:在水汽强吸收波段,卷云大气反射率随卷云高度和光学厚度的增加而增大、随卷云粒子有效尺度的增大而减小;目标背景对比度受卷云参数的影响较大,尤其当目标高度在7km以下时卷云对目标观测的干扰很大。

The reflectance of strong absorption band in condition of cirrus atmosphere is simulated by the general atmospheric radiation transmission software.The effects of cirrus particle＇s shape and effective size,optical thickness and cirrus altitude on atmospheric top reflectance and background radiation are analyzed.A radiation intensity calculation model of high-temperature gas target is established and the spectral radiation characteristics of target radiation transmitted to the top of atmosphere in cirrus atmosphere are obtained by simulation.The target background contrast at the top of atmosphere is computed,and the influences of cirrus characteristic parameters and target altitude on target background contrast are also discussed.Results show that cirrus atmospheric reflectance increases with the increasing of cirrus altitude and optical thickness,and decreases with the increasing of cirrus particle effective size in the strong absorption band of vapor.The target background contrast is greatly affected by cirrus parameters.The presence of cirrus has a big disturbance to target observation,especially when the target altitude is below 7km.