基于大气辐射传输和δ-二流近似的斜程能见度反演方法  

Slant-Range Visibility Retrieval Method Based on Atmospheric Radiative Transfer andδ-Two-Stream Approximation

作　　者：马愈昭[1,2] 朱峻 张宇航 Ma Yuzhao;Zhu Jun;Zhang Yuhang(Tianjin Key Laboratory for Advanced Signal Processing,Civil Aviation University of China,Tianjin 300300,China;College of Electronic Information and Automation,Civil Aviation University of China,Tianjin 300300,China)

机构地区：[1]中国民航大学天津市智能信号与图像处理重点实验室,天津300300 [2]中国民航大学电子信息与自动化学院,天津300300

出　　处：《光学学报》2023年第12期37-47,共11页Acta Optica Sinica

基　　金：国家自然科学基金(U1833111)。

摘　　要：从能见度定义出发,提出采用SBDART辐射传输模式结合CALIPSO卫星数据求解辐射传输方程,对华北地区斜程能见度进行了详细的仿真与分析。首先,使用SBDART模式结合CALIPSO卫星数据获取实际条件下天空背景辐射亮度。然后,根据斜程能见度探测原理,得到斜程能见度所处区间,进而采用δ-二流近似估计区间内部辐射亮度分布,从而反演得到精确的斜程能见度。结果表明,采用CALIPSO卫星数据结合SBDART模式模拟大气辐射传输过程,计算结果与MERRA-2辐射数据变化趋势一致,相关系数达到0.949;使用δ-二流近似能更加高效地模拟辐射传输过程,且提出方法结果与SBDART模式保持较好的一致性,两者相对误差在14.3%以内;当斜程能见度小于1 km时,使用提出方法反演斜程能见度同经验公式相比误差约为7.1%,且适用于15°以外以及向上观测的斜程能见度探测。Objective Atmosphere visibility is an important and popular indicator for evaluating the atmosphere quality and is of great significance for our daily life and traffic safety.According to the observation paths,visibility can be defined as horizontal visibility and slantrange visibility.In some cases,slantrange visibility may be different from horizontal visibility to some degree.In civil aviation,horizontal visibility or ground visibility is normally measured by groundbased equipment called transmissometer.Reported horizontal visibility is employed for air traffic management.However,slantrange visibility is more important for pilots during flights.Thus,far slantrange visibility has not been applied in air traffic management,which is due to the absence of feasible methods for deriving or measuring slantrange visibility.The spaceborne lidar CALIOP carried by the sunsynchronous satellite CALIPSO is capable of obtaining the atmosphere properties along the vertical direction,and therefore,it is a good candidate for deriving the slantrange visibility.We aim to develop a sufficient method of deriving slantrange visibility with high accuracy based on the aerosol data provided by CALIPSO and the theory of atmosphere radiative transfer.Methods We successfully derive the slantrange visibility for North China through the aerosol data provided by the CALIPSO satellite and the atmosphere radiation transfer model of SBDART.Firstly,the aerosol optical properties are characterized by optical depth,single scattering albedo,and scattering phase function provide by the CALIPSO aerosol products.They are leveraged in solving the atmosphere radiative transfer equation using the SBDART model.As the result,the spatial sky background radiance is obtained.The targetbackground brightness contrast is hence obtained,which is adopted to determine the slantrange visibility based on the visibility definition.Consequently,the atmosphere layer is determined for the desired brightness contrast.Finally,theδtwostream approximation is utilized to est

关 键 词：大气光学 斜程能见度 SBDART δ-二流近似 CALIPSO 

分 类 号：P422.3[天文地球—大气科学及气象学]