基于FY-3E星载红外观测的交叉定标匹配不确定性分析  

Uncertainty analysis of inter-calibration collocation based on FY-3E spaceborne infrared observations

作　　者：杨天杭 张春明[1,2,3] 左丰华 胡勇 顾明剑[1,2] Yang Tianhang;Zhang Chunming;Zuo Fenghua;Hu Yong;Gu Mingjian(Key Laboratory of Infrared System Detection and Imaging Technology,Chinese Academy of Sciences,Shanghai 200083,China;Shanghai Institute of Technical Physics,Chinese Academy of Sciences,Shanghai 200083,China;University of Chinese Academy of Sciences,Beijing 100049,China;School of Optics and Photonics,Beijing Institute of Technology,Beijing 100081,China)

机构地区：[1]中国科学院红外探测与成像技术重点实验室,上海200083 [2]中国科学院上海技术物理研究所,上海200083 [3]中国科学院大学,北京100049 [4]北京理工大学光电学院,北京100081

出　　处：《红外与激光工程》2023年第4期9-20,共12页Infrared and Laser Engineering

摘　　要：星载红外高光谱传感器与多通道光谱传感器在轨交叉定标时能够提升数据精度和质量,交叉定标样本通常采用星下点交叉方式匹配筛选,包括空间、时间、观测几何角度和光谱匹配,匹配误差的不确定性将对最终交叉定标精度产生影响。采用FY-3E同平台红外高光谱大气探测仪HIRAS-II和中分辨率光谱成像仪MERSI-LL均匀晴空背景进行观测,根据视线向量匹配HIRAS-II星下点瞬时视场内的MERSI-LL像素,分别通过模拟视场偏移、观测天顶角偏差和光谱响应函数变化单独分析空间、观测几何角度和光谱匹配误差引入的匹配不确定度。结果表明,空间失配引起观测背景辐射亮温变化,偏移一半像元视场时的相对不确定度约为10%,达到一个像元时为25%~30%;观测几何角度失准引起光谱辐射亮温变化,观测天顶角偏移20°时的不确定度优于0.2%;光谱响应函数差异引起光谱等效辐射亮温变化,响应函数发生展宽时对吸收通道的不确定度最大约为2.5%,窗区通道为0.4%,收缩时的不确定度整体优于0.3%,平移引起的不确定度相对较小,移动5倍波长间隔时优于0.1%。Objective Spaceborne infrared hyperspectral sensors and multi-channel spectral sensors can continuously observe the earth for a long period of time,and have important applications in the fields of climate prediction,weather change,environmental monitoring,etc.The high-precision spectral calibration and radiation calibration of their observation data are crucial to the quantitative application of remote sensing.With the increase of operational time of satellite after being launched,the performance of the spaceborne sensors will change,which will lead to the deviation of observation data accuracy.Therefore,it is necessary to effectively improve the calibration accuracy and the data quality of the instrument through on-orbit inter-calibration.The samples of inter-calibration are generally collocated and filtered through the method of the on-orbit alternative calibration of the Global Space-based Inter-Calibration Sytem(GSICS),including spatial,temporal,observation geometry and spectral collocation through simultaneous nadir overpass(SNO)observations,and consequently achieve the goal of intercalibration with the target sensor.The SNO observations can make two satellite sensors observe the earth from different heights at the similar time and place,which fully reduces the comparison uncertainty caused by different observation time and angle of satellites.This is a necessary prerequisite for the feasibility of inter-calibration,but these factors are also the main source of calibration uncertainty,and the uncertainty of collocating bias will have effects on the inter-calibration accuracy finally.Therefore,we analyze the uncertainty of the samples collocating processing in this paper,including spatial collocation,observation angle collocation and spectral response function collocation between sensors.Methods We establish the sifting process of inter-observation sample pairs above uniform clear-sky background scenes(Fig.1)of the infrared hyperspectral atmospheric sounder HIRAS-II and the low-light medium-resolution spectra

关 键 词：红外交叉定标 交叉匹配 不确定性 

分 类 号：TP732.2[自动化与计算机技术—检测技术与自动化装置]