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题名 近红外波段超精细太阳光谱的地基观测及CO2反演
姓名 霍彦峰
院系 大气科学学院
专业 大气物理学与大气环境
学位名称 理学博士
外文题名 Ground-Based Hyper-Spectral Measurements of the Solar Beam in the SWIR Band and Remote Sensing of Total Column of CO2 in the Earth's Atmosphere
第一导师姓名 田文寿
关键词 二氧化碳;反演;短波红外;高光谱;傅里叶光谱仪;光谱分析仪
外文关键词 Carbon dioxide;Inversion;Shortwave infrared band;Hyper-spectral;Fourier Transform Spectrometer;Optical Spectrum Analyzer
学科 理学
摘要 本文开发了利用近红外波段太阳超精细光谱提取CO2含量的反演算法,并进行了实际反演应用;结合SCIAMACHY和GOSAT碳卫星数据,分析了XCO2的时空变化特征。主要研究内容和结论概括如下: 一. 基于LBLRTM和DISORT,建立了完整的适用于CO2遥感的正演模型。 二. 利用正演模型,分析各要素对CO2反演的影响。结果表明:夫琅禾费线和水汽引起的误差可以通过通道选择来消除。地表反照率和气溶胶对CO2反演的影响小于0.1ppm。反演时应保证响应函数的准确。1hPa地表气压误差引入的反演误差约为0.25ppm。温度对光谱的影响可以通过通道选取来降低。CO2廓线的不准确会引入1-4ppm的反演误差。 三. 发展了基于通道对比值求解XCO2的反演算法。通过优化通道选择,可以避开夫琅禾费线以及水汽强吸收,并降低地表气压、温度廓线、信噪比以及光谱偏移量的影响。利用TCOON的观测光谱进行反演验证的标准差均不超过0.8ppm。 四. 建立了适合于中国碳卫星地面验证系统的XCO2反演算法。算法选取1570.2-1574.2nm波段用于反演,并利用包含1572.75nm处夫琅禾费线的特征波段进行偏移量订正,同时对观测光谱进行分段斜率订正,最后通过使光谱残差最小获得XCO2。 五. 分析了XCO2的时空变化特征。XCO2空间分布呈现明显季节变化特征。南北半球的平均XCO2以各自特有的位相震荡增长。
外文摘要 The method of using ground-based hyper-spectral measurements of the solar beam to improve satellite detection ability of CO2 concentration is a new trend from the past years. However, the understanding about satellite remote sensing and ground-based verification is still limited. Based on the spectrometers from Chinese carbon satellite ground observation network, two algorithms for remote sensing of CO2 from ground-based hyper-spectral measurements of the direct solar beam in shortwave infrared (SWIR) band are developed, one as DOAS (Differential Optical Absorption Spectroscopy) method and the other as optimum estimation method, with the algorithms both applied to observation spectral. Moreover, the spatial and temporal variations of XCO2 from SCIAMACHY and GOSAT are presented. The main results are summarized as following: 1. Based on LBLRTM and DISORT, a complete forward model for remote sensing of CO2 is established according to index parameters of ultra-high resolution spectrometers OSA and FTS125M. 2. Based on the forward model, sensitivity tests for aerosol, surface pressure, temperature, spectral resolution, spectral offset, signal noise ratio (SNR), solar spectrum and so on, are analyzed. The results show that: The higher the spectral resolution, the larger the effect of spectral offset, the inversion errors caused by 0.005 cm-1 spectral offset are respectively about -0.5 and -1.5 ppm for spectral resolution of 0.2 and 0.02 cm-1. The signal noise ratio (SNR) is low if the spectral resolution is too high, while the factors interfering CO2 inversion are not easy to separate if the spectral resolution is too low. The effect of solar spectrum lies in Fraunhofer lines and that of water vapor lies in water vapor absorption lines, thus the inversion errors caused by solar spectrum and water vapor can be eliminated by channel selection. And the inversion errors caused by surface albedo and aerosol are less than 0.1 ppm. The instrument line shape (ILS) has significant influence on inversion, so accurate ILS is necessary. The inversion error caused by 1 hPa surface pressure is about 0.25 ppm, therefore the error of surface pressure in the inversion should be less than 1 hPa. The simulated spectrum errors caused by 1 K temperature profile are larger than that caused by 1 hPa surface pressure, but the impact of temperature can be decreased by channel selection. The inversion error caused by CO...
研究领域 大气辐射与大气遥感
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