摘要
2023年4月发射的风云三号气象卫星G星(FY-3G)是我国首颗专用降水测量卫星,双频降水测量雷达(precipitation measurement radar,PMR)是该颗卫星上最核心的仪器。基于2023年7月数据,利用海洋定标理论模型,模拟海洋表面后向散射截面,与观测海洋表面后向散射截面进行比对,实现对PMR定标精度的初步评估。通过与国外星载双频降水测量雷达(global precipitation measurement,dual-frequency precipitation radar,GPM DPR)海洋定标检验结果比对,评估FY-3G PMR定标的准确性。海洋定标精度检验结果表明:FY-3G PMR Ku波段在入射角小于15°时观测值与模型模拟值的偏差较小,此时FY-3G PMR的偏差为1.65~2.73 dB,偏差标准差为0.74~1.82 dB。FY-3G PMR Ka波段在18°入射角时偏差小于0.27 dB,偏差的标准差为3.49 dB。FY-3G PMR与GPM DPR的定标偏差存在较为固定的偏差,差异主要源自于数据本身的后向散射统计特性,各入射角下FY-3G PMR Ku与Ka波段海洋表面后向散射数据稳定性与GPM DPR相当。
FY-3G precipitation satellite launched in April 2023 is the first dedicated precipitation measurement satellite in China.The dual-frequency precipitation measurement radar(PMR)is the core instrument on the satellite.Because the backscattering performance of the vast ocean area is relatively stable,the calibration accuracy of the on-orbit radar can be tested by studying the backscattering cross-section of the sea surface.FY-3G PMR level 1 data in July 2023 and GPM DPR(global precipitation measurement,dual-frequency precipitation radar)level 2A data are used to analyze the mean value and mean square error of the global sea surface backscattering cross section under no-rain conditions to evaluate the radar performance.At the same time,the theoretical model of ocean surface backscattering is studied to simulate the sea surface backscattering cross-section under the condition of no rain,and the sea surface backscattering crosssection is compared with the actual radar measurement,so as to realize the preliminary evaluation of FY-3G PMR calibration accuracy.Furthermore,the accuracy of FY-3G PMR calibration is evaluated by the ocean calibration test results of GPM DPR data.Test results of ocean calibration accuracy show that when the incidence angle of FY-3G PMR Ku-band is less than 15°,the deviation between the observed value and the model simulation value is small.The deviation of FY-3G PMR ranges from 1.65 to 2.73 dB,while the standard deviation ranges from 0.74 to 1.82 dB.The deviation of FY-3G PMR Ka-band at an 18°incidence is less than 0.27 dB,and the standard deviation of the deviation is 3.49 dB.The calibration deviation of FY-3G PMR and GPM DPR is relatively constant,with the difference is primarily attributed to the backscattering statistical characteristics of the data itself.The stability of the backscattering data of FY-3G PMR Ku-and Ka-band sea surfaces at each incidence angle is comparable to that of GPM DPR.Gas attenuation is not considered at the moment.In the future,the impact of gas attenuation on th
作者
袁梅
尹红刚
商建
江柏森
杨润峰
谷松岩
张鹏
Yuan Mei;Yin Honggang;Shang Jian;Jiang Baisen;Yang Runfeng;Gu Songyan;Zhang Peng(National Satellite Meteorological Center/National Center for Space Weather,Beijing 100081;Innovation Center for Fengyun Meteorological Satellite,Beijing 100081;Key Laboratory of Radiometric Calibration and Validation for Environmental Satellites,Beijing 100081;Beijing Research Institute of Telemetry,Beijing 100076;Meteorological Observation Center,CMA,Beijing 100081)
出处
《应用气象学报》
CSCD
北大核心
2024年第5期526-537,共12页
Journal of Applied Meteorological Science
基金
中国气象局青年创新团队(CMA20240N10)
国防科工局“十四五”民用航天预研项目(D040204,D030303)
中国科学院国际伙伴计划项目(183311KYSB20200015)。
关键词
降水测量雷达
FY-3G
后向散射截面
海洋定标
精度检验
precipitation measurement radar
FY-3G
backscattering cross section
ocean calibration
accuracy validation
