摘要
星载高光谱大气温度和成分廓线临边探测仪(临边成像探测仪)运行在太阳同步轨道,采用临边扫描方式探测氧气A带气辉。由于氧气的较强吸收,在地面很难观测到气辉谱线以验证临边成像探测仪的探测能力,因此需要对其响应谱线进行仿真研究。首先获取临边成像探测仪的工作参数如轨道高度520 km、扫描高度10~100 km、扫描间隔2 km;其次基于实验室定标获取光谱、辐射响应参数,对特征峰和像元配对后进行多项式拟合得到光谱探测范围为498.1~802.3 nm,对特征峰进行拟合得到光谱分辨率1.38 nm。辐射定标得到扫描镜不同指向角度的相对偏差为±0.5%,对不同等级辐亮度和响应值Digital Number(DN)进行最小二乘法拟合得到所有积分时间(最短25 ms、最长3200 ms)的辐射定标系数,辐射定标不确定度为3.6%;然后计算气辉谱线,对大气进行分层得到气辉传输的视线段长度,结合Mass Spectrometer and Incoherent Scatter(MSIS)模型和HIgh-resolution TRansmission molecular AbsorptioN(HITRAN)数据库配置每层大气参数,得到气辉在80 km以上的透过率达到0.9,在60 km受到较强的氧气吸收,透过率低于0.05,对于每层大气中的气辉辐射强度,采用剥洋葱算法对SCanning Imaging Absorption spectrometer for Atmospheric CHartographY(SCIAMACHY)在轨观测的气辉谱线进行反演获取气辉体辐射率,基于视线段长度、大气透过率得到高分辨率气辉谱线的辐射强度。最后将高分辨率谱线和光谱响应函数进行卷积得到临边成像光谱仪分辨率下的气辉谱线形状,结合定标的辐射响应系数得到气辉谱线响应DN值。仿真结果表明,临边成像探测仪能够有效探测出气辉谱线,谱线形状可以表征其对温度的依赖性,在3.2 s最长曝光时间能够获取较好的信噪比。气辉谱线仿真贯通了气辉辐射源强度计算、大气层传输特性、光谱仪响应DN值输出,此方法不但能够评价成像光谱仪的气辉探测能力,也能够应用于在轨遥感数据的反演,为发展中高层大气的探测提供科学支撑。
The spaceborne limb imaging spectrometer(LIS)operates in a sun-synchronous orbit and uses limb scanning to detect oxygen A-band airglow.Due to the strong absorption of oxygen,it is difficult to observe airglow emission from the ground,which limits the LIS's detection capability.Therefore,the spectral simulation method is discussed in this paper.Firstly,we obtain the LIS's working parameters,including a track altitude of 520km,a scanning altitude of 10~100km,and a scanning interval of 2km.Secondly,based on laboratory calibration,spectral and radiation response parameters were obtained.The spectral calibration matched the lamp peaks and pixels.The polynomial fitting results show that the spectral range of LIS is 498.1~802.3nm,with a spectral resolution of 1.38nm obtained by Gaussian fitting.For radiometric calibration,the radiometric relative deviation at different pointing angles is±0.5%.The least squares method was used to fit the radiance and response Digital Number(DN)values to obtain the radiation calibration coefficients for all integration times(ranging from 25ms to 3200ms)with a radiation calibration uncertainty of 3.6%.Based on the airglow transmission length,the Mass Spectrometer and Incoherent Scatter(MSIS)model,and High-resolution Transmission molecular Absorption(HITRAN)database,the airglow transmittance is calculated.The results show that airglow transmittance is less affected by oxygen absorption above 80km,with a transmittance of 0.9,and stronger oxygen absorption at 60km,with a transmittance of less than 0.05.Based on the airglow observed by the Scanning Imaging Absorption spectrometer for Atmospheric CHartographY(SCIAMACHY),the onion-peeling method was used to obtain the volume emission rates,and then high-resolution airglow emissions were calculated,which vary at different target heights.Finally,the high-resolution airglow emission convolved with the response function,combined with the calibrated radiation response coefficient,yields the DN value of the airglow response of LIS.The results show that LIS can effectively detect airglow emission,and the spectral shape can characterize its temperature dependence.LIS has a good signal-to noise ratio at the longest exposure time of 3.2seconds.Through this simulation,the airglow detection capability and inversion algorithm of imaging spectrometers can be evaluated,providing scientific support for the exploration of the middle and upper atmosphere.
作者
赵敏杰
司福祺
周海金
江宇
汪世美
詹锴
闫格
ZHAO Min-jie;SI Fu-qi;ZHOU Hai-jin;JIANG Yu;WANG Shi-mei;ZHAN Kai;YAN Ge(Hefei Institutes of Physical Science,Chinese Academy of Sciences,Hefei 230031,China;Jianghuai Advanced Technology Center,Hefei 230000,China)
出处
《光谱学与光谱分析》
北大核心
2025年第9期2437-2444,共8页
Spectroscopy and Spectral Analysis
基金
江淮前沿技术协同创新中心追梦基金(2023-ZM01K006)
国家重点研发计划项目(2023YFC3705104)资助。
关键词
临近空间
大气氧气辉
临边探测
星载成像光谱仪
谱线仿真
Near space
Atmospheric oxygen airglow
Limb-viewing
Space-borne limb imaging spectrometer
Spectral simulation
作者简介
赵敏杰,1987年生,中国科学院合肥物质科学研究院副研究员,e-mail:mjzhao@aiofm.ac.cn;通讯作者:司福祺,e-mail:sifuqi@aiofm.ac.cn。
