摘要
我国自主研发的全球首颗民用晨昏轨道气象卫星风云三号E星于2021年7月5日在酒泉卫星发射中心成功发射,其上搭载的红外高光谱大气垂直探测仪二型FY-3E HIRAS-Ⅱ(Fengyun-3E Hyperspectral Infrared Atmospheric Sounder-Ⅱ)作为FY-3D HIRAS的延续,仪器指标在各方面都有大幅提升,因此在轨评估对检验仪器光谱资料质量至关重要.本文基于星下点交叉对比SNO(Simultaneous Nadir Overpass)方法,将FY-3E HIRAS-Ⅱ和FY-3D HIRAS的观测资料分别与国际公认精度较高的Metop-B IASI(Meteorological Operational-B the Infrared Atmospheric Sounding Interferometer)观测资料做匹配,经过时间、空间、观测几何和光谱匹配后得到SNO匹配对,通过计算亮温平均偏差和偏差标准差,并分析平均偏差与匹配对平均亮温的散点分布关系,评估FY-3E HIRAS-Ⅱ光谱资料的精度.结果表明:长波红外波段中,HIRAS-Ⅱ/IASI的大多数通道在两极的偏差绝对值低于0.5 K,在650~700 cm^(-1)强CO_(2)吸收波段内HIRAS-Ⅱ观测质量有所提高,HIRAS-Ⅱ在南极地区的标准差低于HIRAS.中波红外波段中,HIRAS-Ⅱ与HIRAS重叠的水汽吸收带波段内偏差标准差均小于1 K,在HIRAS-Ⅱ新增的水汽吸收波段内,标准差随波数增加略微增加.短波红外波段中,HIRAS-Ⅱ新增的波段标准差在1 K左右,个别通道的偏差与标准差出现异常增大.在2250~2380 cm-1波段内HIRAS-Ⅱ/IASI与HIRAS/IASI的偏差和标准差增大,其原因是高层大气受非局地热力平衡NLTE(Non-Local Thermodynamic Equilibrium)效应的影响,HIRAS-Ⅱ所受影响小于HIRAS.由于HIRAS-Ⅱ载于晨昏轨道卫星,观测过程中太阳对其影响很小,IASI与HIRAS则受太阳辐射影响,因此在大于2400 cm-1波数的波段HIRAS-Ⅱ与IASI偏差较大,且当观测亮温高于245 K时,HIRAS-Ⅱ/IASI的平均偏差与平均亮温呈线性升高趋势.
Fengyun-3E,the world's first civilian early-morning-orbit meteorological satellite independently developed by China,was successfully launched from Jiuquan Satellite Launch Center on July 5,2021.As a continuation of Fengyun-3D Hyperspectral Infrared Atmospheric Sounder(FY-3D HIRAS),the FY-3E HIRAS-Ⅱhas significantly improved in all aspects.Therefore,onboard evaluation is very important to the quality of observed spectrum.In this paper,based on the simultaneous nadir overpass(SNO)method,the spectrum of FY-3E HIRAS-Ⅱand FY-3D HIRAS are respectively matched with the Meteorological Operational-B the Infrared Atmospheric Sounding Interferometer(METOP-B IASI)'s high precision spectrum.After the matching of time,space,observation geometry angle and spectrum,the SNO matching pair is obtained.The accuracy of FY-3E HIRAS-Ⅱspectrum was evaluated by calculating the mean bias and standard deviation of brightness temperature,and analyzing the scatter distribution relationship between the mean bias and the average of matching pairs'brightness temperature.The results showed that:In the long-wave infrared band,the absolute mean bias of most channels of HIRAS-Ⅱ/IASI is less than 0.5 K at the poles,and the observation quality of HIRAS-Ⅱis improved in the 650~700 cm-1 which is strong CO_(2)absorption band.The standard deviation of HIRAS-Ⅱin the Antarctic region is lower than that of HIRAS.In the mid-wave infrared band,the standard deviation of the overlapping water vapor absorption band of HIRAS-Ⅱand HIRAS is less than 1 K.In the newly added water vapor absorption band of HIRAS-Ⅱ,the standard deviation increases slightly with the increase of wavenumber.In the short-wave infrared band,the standard deviation of the newly added band of HIRAS-Ⅱis about 1 K,meanwhile the bias and standard deviation of some channels are abnormally increased.There is an increase of the bias and standard deviation between HIRAS-Ⅱ/IASI and HIRAS/IASI in the band 2250~2380 cm-1,which is due to the influence of Non-Local Thermodynamic Equilibrium(NLTE)in the upper atmosphere,and HIRAS-Ⅱis less affected than HIRAS.Since HIRAS-Ⅱis carried on the early-morning-orbit satellite,the sun has little influence on it during the observation process,while IASI and HIRAS are affected by solar radiation.Therefore,HIRAS-Ⅱand IASI have a large mean bias when the wavenumber is greater than 2400 cm-1.When the observed brightness temperature is higher than 245 K,The mean bias of HIRAS-Ⅱ/IASI increased linearly with the average brightness temperature.
作者
廖翼
官莉
LIAO Yi;GUAN Li(Nanjing University of Information Science and Technology,Nanjing 210044,China;Key Laboratory of Meteorological Disaster(NUIST),Ministry of Education,Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters,Nanjing University of Information Science and Technology,Nanjing 210044,China)
出处
《地球物理学进展》
CSCD
北大核心
2023年第3期977-986,共10页
Progress in Geophysics
基金
国家自然科学基金资助项目(41975028)资助。
