摘要
红外高光谱探测仪的高精度辐射定标是其定量化应用的关键。基于欧洲气象卫星MetOp-A/B星红外大气探测干涉仪(IASI)与风云三号D星(FY-3D),采用瞬时星下点交叉比对方法,评估FY-3D搭载的红外高光谱大气探测仪(HIRAS)辐射定标的相对偏差。根据两个仪器严格的空间和时间匹配观测数据,采用与FY-3D同一平台但空间分辨率更高的中分辨率光谱成像仪MERSI-II的数据,筛选匹配样本的均匀背景。在交叉比对前,将IASI数据光谱分辨率用傅里叶正逆变换转换为与HIRAS相同的光谱分辨率。由于满足匹配规则的比对样本基本分布在目标温度较低的南北极区域,因此用光谱亮温的平均偏差和偏差标准差评价交叉比对结果。结果表明,HIRAS与MetOp-A/B星的IASI比对结果相似,在相对温度较高的北极区域的一致性整体优于南极区域。低温目标环境下,长波、中波红外的亮温平均偏差小于1 K,多数通道小于0.5 K,一致性良好,各通道无明显温度依赖,偏差标准差小于2 K,且随光谱通道而变,在吸收线剧烈的位置处稍大。短波红外HIRAS光谱的亮温整体低于IASI光谱,多数通道的平均偏差小于1.5 K,偏差对温度的依赖较明显,偏差标准差随目标温度升高而减小。亮温偏差长期趋势(2018年4-12月)的分析表明,其长期整体稳定,短波偏差在较低目标温度下稍大。
High-precision radiometric calibration of hyperspectral infrared sounders is crucial for its quantitative application.In this study,the relative deviation obtained by radiance calibration of infrared hyperspectral atmospheric sounder(HIRAS)on FY-3 D satellite is evaluated based on infrared atmospheric sounding interferometer(IASI)on European meteorological satellites MetOp-A and MetOp-B and Y-3 D satellite through simultaneous nadir overpass.According to the observation data of strictly spatial and temporal matching of both instruments,the uniform scenes are selected by using the higher spatial resolution data of medium resolution spectral imager(MERSI-II)on the same platform of FY-3 D.The spectral resolution of IASI data is converted to the same spectral resolution of HIRAS through forward-inverse Fourier transform method before inter-comparison.Because the matching samples which satisfy the collocation criteria are distributed in the North and South Arctic regions with low target temperatures,the inter-comparison results are evaluated by mean and standard deviation of HIRAS-IASI brightness temperature(BT).The results show that the comparison results between HIRAS and MetOp-A/B are similar,the consistency of North Arctic regions with high temperature is better than that of South Arctic regions.HIRAS agrees well with IASI at the long-wave IR(LWIR)and middle-wave IR(MWIR)in low temperature environment with less than 1 K mean deviation and below 0.5 K in most channels.There are no apparent scene-dependent features for individual spectral channels,the standard deviation is less than 2 K,and varies with the spectral channels,slightly larger at the position where the absorption line is sharp.The spectral BT of HIRAS is lower than that of IASI with<1.5 K mean deviation in most channels at short-wave IR(SWIR),the deviation shows scene-dependent features,and the standard deviation decreases as the target temperature increases.The long-term trend of BT difference(from April to December,2018)analysis shows that long-term consistency of HIRAS is stable,the mean deviation at SWIR is slightly larger in the lower target temperature conditions.
作者
杨天杭
胡秀清
徐寒列
吴春强
漆成莉
顾明剑
Yang Tianhang;Hu Xiuqing;Xu Hanlie;Wu Chunqiang;Qi Chengli;Gu Mingjian(Key Laboratory of Infrared System Detection and Imaging Technology,Chinese Academy of Sciences,Shanghai 200083,China;University of Chinese Academy of Sciences,Beijing 100049,China;Sha?ighai Institute of Technical Physics,Chinese Academy of Sciences,Shanghai 200083,China;Key Laboratory of Rad iometric Calibration and Validation for Environmental Satellites,National Satellite Meteorological Center,Beijing 100081,China)
出处
《光学学报》
EI
CAS
CSCD
北大核心
2019年第11期369-379,共11页
Acta Optica Sinica
基金
国家重点研发计划(2018YFB0504900,2018YFB0504901,2018YFB0504800,2018YFB0504802)
国家自然科学基金(41871249,41471302)
关键词
光谱学
交叉比对
红外高光谱大气探测仪
低温目标
辐射一致性
spectroscopy
inter-comparison
hyperspectral infrared atmospheric sounder
low temperature target
radiometric consistency
