基于地对空观测光谱的大气CO_2柱浓度反演分析（英文）

Retrieval and Analysis of Atmospheric XCO_2 Using Ground-Based Spectral Observation

基于地对空高光谱观测获取大气CO2柱浓度（大气中CO2的垂直总含量）数据是验证和改进卫星高光谱观测反演CO2浓度的重要数据源之一，而目前在中国还没有基于地面光谱观测进行大气CO2柱浓度反演研究的报告。利用光谱分析仪与太阳跟踪仪等构成的地面观测系统在中国内蒙古锡林郭勒草原进行了地对空高光谱观测，基于高光谱观测数据反演了大气CO2柱浓度。在基于1.6μm大气CO2的光谱吸收特征进行CO2浓度反演过程中，评价分析了观测光谱的波长漂移和气象参数对大气CO2柱浓度反演精度的影响。结果显示观测期间平均大气CO2柱浓度为390.9μg · mL -1。波长的漂移将会导致反演浓度值整体偏低；波长漂移从-0.012～0.042 nm范围时，将会导致1μg · mL -1以上的偏差。同时，研究发现光谱透过率在6357～6358，6360～6361和6363～6364 cm -1谱段敏感于气象参数的变化。对比利用与光谱观测同时和非同时观测的气象参数进行的浓度反演结果发现，非同时观测气象参数的利用引起的浓度偏差最小在0.11μg · mL -1，最大可达4μg · mL -1；本论文的分析结果对基于光谱反演CO2柱浓度算法的改进有着一定的参考价值。

Atmospheric CO2 column concentration （column-averaged dry air mole fractions of atmospheric car-bon dioxide） data obtained by ground-based hyperspectral observation is an important source of data for the verification and improvement of the results of CO 2 retrieval based on satellite hyperspectral observation .How-ever ,few studies have been conducted on atmospheric CO2 column concentration retrieval based on ground-based spectral hyperspectral observation in China .In the present study ,we carried out the ground-based hy-perspectral observation in Xilingol Grassland ,Inner Mongolia of China by using an observation system which is consisted of an optical spectral analyzer ,a sun tracker ,and some other elements .The atmospheric CO2 column concentration was retrieved using the observed hyperspectral data .The effect of a wavelength shift of the ob-servation spectra and the meteorological parameters on the retrieval precision of the atmospheric CO 2 concen-tration was evaluated and analyzed .The results show that the mean value of atmospheric CO 2 concentration was 390.9 μg · mL -1 in the study area during the observing period from July to September .The shift of wave-length in the range between -0.012 and 0.042 nm will generally lead to 1 μg · mL -1 deviation in the CO2 re-trievals .This study also revealed that the spectral transmittance was sensitive to meteorological parameters in the wavelength range of 6 357~6 358 ,6 360~6 361 ,and 6 363~6 364 cm-1 .By comparing the CO2 retriev-als derived from the meteorological parameters observed in synchronous and non-synchronous time ,respective-ly ,with the spectral observation ,it was showed that the concentration deviation caused by using the non-syn-chronously observed meteorological parameters is ranged from 0.11 to 4μg · mL -1 .These results can be used as references for the further improvement of retrieving CO2 column concentration based on spectral observa-tion .