基于深对流云的FY-3D/MERSI-Ⅱ反射太阳波段辐射响应评估  

Radiometric Response Evaluation of FY-3D/MERSI-ⅡReflective Solar Bands Based on Deep Convective Cloud

作　　者：张北 胡秀清[1,2] 周为伟 王玲 陈林[1,2] 张鹏 Zhang Bei;Hu Xiuqing;Zhou Weiwei;Wang Ling;Chen Lin;Zhang Peng(National Satellite Meteorological Center(National Center for Space Weather),Key Laboratory of Radiometric Calibration and Validation for Environmental Satellites,China Meteorological Administration,Beijing 10o08l,China;Innovation Center for FengYun Meteorological Satellite(FYSIC),Beijing 100081,China;School of Surveying and Land Information Engineering,Henan Polytechnic University,Jiaozuo 454003,Henan,China)

机构地区：[1]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 [2]许健民气象卫星创新中心,北京100081 [3]河南理工大学测绘与国土信息学院,河南454003

出　　处：《光学学报》2023年第18期358-370,共13页Acta Optica Sinica

基　　金：国家重点研发计划(2022YFB3902901)。

摘　　要：风云三号D星(FY-3D)中分辨率光谱成像仪Ⅱ型(MERSI-Ⅱ)已在轨运行超过5年,经定量应用反演发现部分通道辐射响应性能出现明显退化。本研究采用深对流云(DCC)目标对MERSI-Ⅱ大部分反射太阳波段辐射响应变化进行趋势评估,为提高该方法的稳定性,对基础DCC定标方法进行了优化。首先,比较了当前两种DCC双向反射分布函数(BRDF)模型的校正效果,采用月度反射率概率密度函数(PDF)众数和均值分别对反射率长时间序列稳定性进行分析。结果表明:对可见光和近红外波段使用CERES厚冰云BRDF模型校正的反射率PDF众数较优;短波红外波段反射率PDF均值较优,但对于两种BRDF模型均不敏感。其次,针对BRDF模型在短波红外波段无明显校正效果的问题,提出了一种基于反射率拟合残差和滑动平均值的去季节性方法。该方法显著改善了2018-2022年短波红外波段月度DCC反射率序列的相对标准差和波动性,分别降低了约22.2%和53%。这种去季节性方法为其他卫星光学传感器基于DCC目标的辐射定标研究提供了参考。最后,使用上述方法对MERSI-Ⅱ的11个反射太阳波段辐射响应进行定量评估,发现蓝光通道和全部短波红外通道出现显著衰减,该评估结果将作为FY-3D/MERSI-Ⅱ业务定标更新的重要参考依据。Objective The FY-3D medium resolution spectral imager(MERSI-Ⅱ)has been in orbit for more than five years.Quantitative application inversion shows that the radiometric response of some channels has deteriorated significantly,seriously affecting the accuracy of satellite quantitative remote sensing products.Therefore,it is necessary to evaluate the radiometric response of the MERSI-Ⅱand update the operation calibration according to the evaluation results.Compared with traditional targets such as deserts and glaciers,deep convective cloud(DCC)features a higher signal-to-noise ratio,isotropic reflection characteristics close to Lambertian,and minimum water vapor absorption.In-orbit calibration methods based on DCC target are widely employed to monitor the radiation performance of satellite sensors.However,the uncertainty factors in the DCC calibration method will affect the accuracy and stability,such as DCC bidirectional reflectance distribution function(BRDF)correction model,reflectivity probability density function(PDF)eigenvalues,and seasonal fluctuations.In this study,the basic DCC calibration method is optimized.Firstly,the BRDF correction effects of the Hu model and CERES thick ice cloud model are compared,as well as the stability of PDF mode and the mean of DCC reflectivity.Secondly,a deseasonal method based on reflectivity fitting residual and the moving average is proposed as the BRDF correction model of DDC is invalid in the SWIR band.Finally,the radiation performance of FY-3D/MERSⅡreflected solar bands is quantitatively evaluated by the optimization method.The evaluation results will be adopted as an important basis for the service calibration update of MERSI-Ⅱreflected solar bands.Methods We utilize DCC targets to evaluate the trend of radiometric response changes in most of the MERSI-Ⅱreflected solar bands.Firstly,the DCC target pixels are identified according to the infrared 10.8μm channel brightness temperature threshold,observation geometric conditions(latitude,solar zenith angle,observati

关 键 词：遥感和传感器 辐射定标 深对流云 双向反射分布函数 中分辨率光谱成像仪 

分 类 号：TP732[自动化与计算机技术—检测技术与自动化装置]