FY-3C MWRI在轨交叉辐射定标  

Intercalibration of the Microwave Radiation Imager on Fengyun 3C

作　　者：曾子倩 蒋耿明[1] Zeng Ziqian;Jiang Gengming(Key Laboratory of Information Science for Electromagnetic Waves,Ministry of Education,Fudan University,Shanghai 200433,China)

机构地区：[1]复旦大学电磁波信息科学教育部重点实验室,上海200433

出　　处：《遥感技术与应用》2021年第3期682-691,共10页Remote Sensing Technology and Application

基　　金：国家重点研发计划项目“国产多系列遥感卫星历史资料再定标技术”(2018YFB0504900、2018YFB0504902)。

摘　　要：精确辐射定标是定量遥感的基础。以搭载在全球降水测量(Global Precipitation Measurement,GPM)卫星上的微波成像仪(GPM Microwave Imager,GMI)为辐射基准,用双差异(Double Difference,DD)方法对搭载在我国风云三号C星(Fengyun 3C,FY-3C)上的微波成像仪(Microwave Radiation Imager,MWRI)进行在轨交叉辐射定标。首先,将FY-3C MWRI数据、GMI数据和第五版欧洲中尺度天气预报中心再分析(European Centre for Medium-Range Weather Forecast Re-Analysis V5,ERA5)数据重采样至1°×1°的全球规则格网空间;其次,根据匹配条件收集晴空海面上的匹配观测点,用海洋微波辐射传输模型分别模拟FY-3C MWRI和GMI各个通道大气顶亮温;然后,根据匹配的观测值和模拟值计算DD值和FY-3C MWRI的理论观测值;最后,确定交叉辐射定标系数,并完成对FY-3C MWRI数据的定标重处理。结果表明:相对于GMI,FY-3C MWRI观测值被低估,特别是低频通道,但随着频率的增大,定标误差逐渐变小。FY-3C MWRI升轨(MWRIA)的定标误差比降轨(MWRID)小1.0~2.0 K。在全球天基交叉辐射定标系统(Global Space-based Inter-Calibration System,GSICS)所定义的标准场景亮温下,对于10V/H、18V/H、23V、36V/H和89V/H共9个通道,MWRIA的辐射定标误差分别为-6.7±0.3 K、-8.7±0.7 K、-2.9±0.7 K、-2.0±0.8 K、-2.4±0.7 K、-4.0±0.8 K、-2.4±1.4 K、-1.3±1.0 K和-0.4±1.8 K;而MWRID的辐射定标误差分别为-7.9±0.7 K、-9.7±0.9 K、-4.3±0.9 K、-3.0±0.8 K、-3.5±0.9 K、-5.1±0.8 K、-3.0±1.1 K、-2.4±0.6 K和-1.0±2.1 K。Accurate radiometric calibration is the fundamental of quantitative remote sensing. In this work,the Microwave Radiation Imager(MWRI)on the Chinese meteorological satellite Fengyun 3C(FY-3C)is intercalibrated against the Microwave Imager on the Global Precipitation Measurement(GMI)using the double difference method. First,the FY-3C MWRI data,GMI data and the fifth edition of the European Centre for Medium-Range Weather Forecast Re-Analysis(ERA5)data are resampled into a 1°×1° regular grid space. Then,matching observations are collected according to matching criteria,and simulations in both FY-3C MWRI and GMI channels at top-of-atmosphere are calculated using the ocean microwave radiative transfer model. Next,the double differences and theoretic observations in FY-3C MWRI channels are computed. Finally,the intercalibration coefficients are determined,and the FY-3C MWRI data are re-calibrated. The results show that,against GMI,the observations in FY-3C MWRI channels are underestimated,especially for the low frequency channels,and the calibration bias decreases with the frequency increment. The calibration biases of FY-3C MWRI ascending(MWRIA)data are 1.0 K~2.0 K lower than that of FY-3C MWRI descending(MWRID)data. At the standard scene brightness temperatures defined by the Global Space-based Inter-Calibration System(GSICS),in 10 V/H,18 V/H,23 V,36 V/H and 89 V/H channels,the calibration errors of MWRIA are-6.7±0.3 K,-8.7±0.7 K,-2.9±0.7 K,-2.0±0.8 K,-2.4±0.7 K,-4.0±0.8 K,-2.4±1.4 K,-1.3±1.0 K and-0.4±1.8 K,respectively;the calibration errors of MWRIA are 7.9±0.7 K,-9.7±0.9 K,-4.3±0.9 K,-3.0±0.8 K,-3.5±0.9 K,-5.1±0.8 K,-3.0±1.1 K,-2.4±0.6 K and-1.0±2.1 K,respectively.

关 键 词：交叉辐射定标 FY-3C MWRI GMI 双差异法 海洋微波辐射传输模型 

分 类 号：TP75[自动化与计算机技术—检测技术与自动化装置]