FY-3E同平台成像仪对HIRAS-II定位与定标精度评估  

Positioning and Calibration Accuracy Evaluation of HIRAS-II by FY-3E Imager on Same Platform

作　　者：左丰华 胡秀清[2,3] 王霞 漆成莉[2,3] 徐寒列[2,3] 李路 Zuo Fenghua;Hu Xiuqing;Wang Xia;Qi Chengli;Xu Hanlie;Li Lu(School of Optics and Photonics,Beijing Institute of Technology,Beijing 100081,China;Key Laboratory of Radiometric Calibration and Validation for Environmental Satellites,National Satellite Meteorological Center(National Center for Space Weather),China Meteorological Administration,Beijing 100081,China;Innovation Center for FengYun Meteorological Satellite(FYSIC),Beijing 100081,China)

机构地区：[1]北京理工大学光电学院,北京100081 [2]中国气象局中国遥感卫星辐射测量和定标重点开放实验室,国家卫星气象中心(国家空间天气监测预警中心),北京100081 [3]许健民气象卫星创新中心,北京100081

出　　处：《光学学报》2022年第24期232-240,共9页Acta Optica Sinica

基　　金：国家重点研发计划(2018YFB0504901);国家自然科学基金(41871249)。

摘　　要：我国晨昏轨道气象卫星风云三号E星(FY-3E)上搭载了红外高光谱大气探测仪Ⅱ型(HIRAS-Ⅱ),该仪器的高地理定位精度和辐射定标精度是其观测资料定量化应用的关键。采用交叉比对方法,基于同卫星平台搭载的中分辨率光谱成像仪-微光型(MERSI-LL),评估HIRAS-Ⅱ的地理定位和辐射定标相对偏差。两台仪器的观测数据样本经空间匹配后,采用MERSI-LL数据评估匹配样本的观测背景均匀性,用海陆或云体边界的非均匀背景观测样本评估HIRAS-Ⅱ的地理定位精度,用晴空海洋等场景的均匀背景观测样本评估HIRAS-Ⅱ的辐射定标精度。在交叉比对前,将HIRAS-Ⅱ观测辐射光谱与MERSI-LL各红外通道光谱响应函数积分得到MERSI-LL各红外通道的高光谱模拟观测数据。结果表明:星下点处HIRAS-Ⅱ地理定位沿轨道方向偏离3.53 km,沿跨轨道方向偏离2.01 km;在辐射定标精度方面,HIRAS-Ⅱ与MERSI-LL多数通道的辐射亮温(BT)偏差均值小于0.50 K,偏差标准差小于0.40 K,仅4.05μm通道对低温目标的偏差较大,且该通道温度依赖明显;4.05μm通道BT偏差随扫描角度呈现波动性变化,8.55μm通道BT偏差随扫描角度变化不明显,其他通道BT偏差随扫描角度的变化规律与目标温度有关;偏差长时间序列分析表明,BT偏差整体保持稳定。The Infrared Hyperspectral Atmospheric SounderⅡ(HIRAS-Ⅱ)is mounted on China’s Fengyun-3E satellite(FY-3E),a meteorological satellite in dawn-dusk orbit.The high geolocation accuracy and radiometric calibration accuracy of the instrument are the keys to the quantitative application of its observational data.The relative deviations of geolocation and radiometric calibration of HIRAS-Ⅱare evaluated via cross-comparison by the Moderate Resolution Spectral Imager-Low Light(MERSI-LL)mounted on the same satellite platform.After the observational data samples of the two instruments are spatially matched,the MERSI-LL data is used to evaluate the observation background uniformity of the matched samples.The geolocation accuracy of HIRAS-Ⅱis evaluated with non-uniform background observation samples of sea-land or cloud boundary,and its radiometric calibration accuracy is evaluated with homogeneous background observation samples of clear-sky ocean and other scenes.Before cross-comparison,the hyperspectral simulated observational data of each infrared channel in MERSI-LL is obtained by integrating the HIRAS-Ⅱobserved radiation spectrum with the spectral response function of each infrared channel in MERSI-LL.The results show that the geolocation of HIRAS-Ⅱat nadir deviates by 3.53 km in the along-orbit direction and 2.01 km in the cross-orbit direction.In terms of radiometric calibration accuracy,the mean radiation brightness temperature(BT)deviations of most channels in HIRAS-Ⅱand MERSI-LL are lower than 0.50 K,and the standard deviation of the deviations is lower than 0.40 K.Only the deviation of the 4.05μm channel is large to the low-temperature target,and the temperature dependence of this channel is obvious.The BT deviation of the 4.05μm channel fluctuates while that of the 8.55μm channel does not change significantly with the scanning angle.The variations in the BT deviations of the other channels with the scanning angle are related to the target temperature.The long time series analysis of the BT devia

关 键 词：光谱学 红外高光谱大气探测仪Ⅱ型 中分辨率光谱成像仪-微光型 地理定位 辐射定标 

分 类 号：P414.4[天文地球—大气科学及气象学]