摘要
基于高分辨率傅里叶变换红外太阳吸收光谱可以准确测量大气中二氧化碳的柱总量。基于光谱反演算法中的前向模型,分析了改变前向模型中不同参数和不同天顶角情况下对反演结果的影响及其原因。选取具有代表性的两天的测量光谱,改变前向模型中连续体倾斜量值、内部视场角、零偏置和多普勒效应四个模型参数,观察不同先验模型参数的扰动对二氧化碳测量结果的影响。结果表明,不同模型参数的扰动引起反演的二氧化碳柱平均干空气混合比(XCO_2)相对偏差并不一样;不同的测量时间,相同参数扰动引起的二氧化碳含量相对偏差也不同。其中连续体倾斜量值的变化对反演结果的影响最大,其变化引起的相对偏差波动范围在0.1%~0.2%之间;内部视场角、零偏置和多普勒效应的变化对反演结果影响较小,引起的二氧化碳的相对偏差分别在-0.045%~0.02%,-0.045%~0.015%和-0.03%~0.04%之间。最后用二氧化碳反演平均核解释了反演误差来源。研究结果对光谱反演算法中模型参数的设定和提高测量的准确度提供了理论依据。
Solar absorption spectra collected with a high-resolution Fourier transform spectrometer is able to measure the column abundance of CO2 accurately.In the paper,the influence of a model parameters in the forward model on the retrieval of CO2 is analyzed,also the impact of a model parameters on retrieval results under different solar zenith angle and the reasons are discussed.Four model parameters,such as continuum tilt value,internal field of view,zero-level offset and Doppler shift are modified in the forward model and how the results change with the disturbance is studied,based on the spectra collected in two typical days.The results show that,the relative deviations of column-averaged dry air mole fraction of CO2（XCO2）caused by the disturbance of different a model parameters are different.Also,the relative deviations due to the disturbance of the same parameters corresponding to different time for collecting spectra are different.Continuum tilt value has the biggest influence on the retrieval,and the change of this value resulted in the relative deviations of XCO2 between 0.1%~0.2%.The changes of other three parameters internal field of view,zero-level offset and Doppler shift have small impact on the retrieval,which leads to the relative deviations of XCO2 in the range of-0.045%^-0.02%,-0.045%~0.015% and-0.03%~0.04%,respectively.Finally,the reasons of the deviations are explained based on the average kernels of CO2.The results provide a basis for how to set the parameters in the retrieval algorithms and improve the measurement accuracy of atmospheric CO2.
作者
单昌功
刘诚
王薇
孙友文
刘文清
田园
杨维
SHAN Chang-gong LIU Cheng WANG Wei SUN You-wen LIU Wen-qing TIAN Yuan YANG Wei(School of Environment Science and Optoelectronic Technology, University of Science and Technology of China, Hefei 230031, China School of Earth and Space Sciences, University of Science and Technology of China, Hefei 230031, China Key Laboratory of Environmental Optics and Technology, Anhui Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Hefei 230031, China)
出处
《光谱学与光谱分析》
SCIE
EI
CAS
CSCD
北大核心
2017年第7期1997-2003,共7页
Spectroscopy and Spectral Analysis
基金
国家自然科学基金项目(41405134
41575021
91544212
41605018)
安徽省自然科学基金项目(1608085MD79)
重点研发计划青年基金项目(2016YFC0200800)资助
关键词
模型参数
傅里叶变换红外光谱
敏感性分析
二氧化碳
A model parameter
Fourier transform Infrared spectroscopy
Analysis of sensitivity
Carbon dioxide
