【作者】 王静；

【导师】 倪国强；

【作者基本信息】 北京理工大学 ， 光学工程， 2015， 博士

【摘要】 利用星载成像光谱仪对地球远紫外（120~180nm）气辉辐射进行全球遥感观测可以掌握电离层中重要参量、主要物质成分的含量和变化规律，包括电离层氧氮比（Column Density of Atomic Oxygen and Molecular Nitrogen，O/N2）、电子密度剖面（Electron Density Profile，EDP）与总电子含量（Total Electron Content，TEC）等。由星载远紫外成像光谱仪观测数据获得电离层参量的反演技术是目前备受关注且亟需解决的问题之一。本课题围绕“由星载远紫外成像光谱数据获取电离层环境参量”这一科学问题展开研究，为未来我国实现地球上层大气和电离层“空间天气”的连续监测和预报提供支撑。首先，阐述紫外气辉辐射的产生机制，推导给定观测方向上气辉辐射强度方程，在大气紫外辐射传输模型的基础上，分析太阳参考谱和O2光吸收横截面对天底和临边气辉辐射强度的影响，提出利用载荷观测的太阳观测光谱对仿真气辉辐射强度进行修正的方法，解决大气紫外传输模型仿真强度的准确性问题，为从远紫外气辉中提取热层和电离层成分及其随外部能量输入响应信息奠定基础。然后，基于大气紫外辐射传输模型，开展由天底扫描氧原子130.4nm日气辉辐射强度推断热层O/N2的反演方法研究。以全球紫外成像仪（Global Ultraviolet Imager，GUVI）的成像几何结构为例，推导卫星观测角和太阳天顶角的计算过程，建立氧原子130.4nm日气辉辐射强度与热层O/N2间的理论模型，并利用HSV颜色—空间直方图相交匹配方法对远紫外遥感O/N2反演结果进行评价。结果表明，氧原子130.4nm日气辉辐射非常适合用于热层O/N2的遥感监测，可大大降低研制电离层遥感星载远紫外成像光谱仪的技术难度。之后，利用全球紫外成像仪临边观测的氧原子135.6nm夜气辉辐射数据进行电离层电子密度剖面反演技术研究。文中建立临边扫描观测模型，从辐射度学的角度推导投影系数矩阵的计算过程，采用正则化与牛顿迭代法相结合的方法，计算得到自由形式电离层电子密度剖面EDP；将自由形式电离层电子密度的峰值高度和峰值电子密度与Chapman型表达式相结合，得到Chapman拟合电子密度剖面，并将其与地基观测数据及全解析型电离层模型（Full Analytic Ionosphere Model，FAIM）进行比较，验证反演算法的有效性。最后，开展由天底扫描氧原子135.6nm夜气辉辐射强度推断电离层总电子含量TEC的反演方法研究。推导天底扫描氧原子135.6nm夜气辉观测值与电离层TEC之间的数学关系，提出基于大气紫外辐射传输模型对观测数据进行辐射校正的方法，为利用远紫外成像光谱仪天底扫描氧原子135.6nm夜气辉辐射监测电离层TEC变化情况提供理论依据。文中，采用三种方法由GUVI天底和临边扫描氧原子夜气辉辐射观测值反演得到电离层TEC，并通过邻近插值法由欧洲定轨中心（Center for OrbitDetermination in Europe，CODE）数据得到近时空分布的TEC对反演得到的电离层TEC进行评价。本文针对星载远紫外成像光谱仪天底和临边两种扫描方式，在国内率先开展由星载成像光谱仪遥感观测数据反演电离层O/N2、EDP和TEC的方法研究，完成了反演过程中涉及重要参数的推导计算，为未来我国发展该项技术提供理论依据和技术支持。更多还原

【Abstract】 The space borne far ultraviolet imaging spectrograph can be used to observe theEarth’s far ultraviolet (FUV) airglow, which can provide us with fundamental diagnosticinformation about the state of the ionosphere and the ionospheric environmental parameters.It’s concerned and necessary to study the retrieval method of using the remote sensingmeasurements of far ultraviolet imaging spectrograph to derive the ionosphere’senvironmental parameters. The thesis is centered on “Retrieving key ionosphericenvironmental parameters from space borne far ultraviolet remote sensing data”, aiming tocontinuously monitor and forecast the space weather of the upper atmosphere.Firstly, the chemical mechanism of far ultraviolet airglow is discussed and theradiance equation for a given observing direction is derived. Based on the AtmosphericUltraviolet Radiance Integrated Code, the influences of the solar reference spectrum and O2absorption cross section on the disk and limb airglow radiance intensity are analyzed, amethod to modify the simulated airglow radiance intensity using the observed solarspectrum is put up, and the problem of the accuracy of the simulated radiance intensity issolved, thus laying a foundation for the research on extracting the information ofthermospheric and ionospheric species and the response to the external energy.Secondly, based on the Atmospheric Ultraviolet Radiance Integrated Code, theretrieval method of using the disk measurements of OI130.4nm dayglow to infer thethermospheric O/N2is investigated. The imaging geometry of Global Ultraviolet Imagerused as an example, the equations of the satellite observing angle and solar zenith angle arederived, the theoretical model between OI130.4nm dayglow and thermospheric O/N2isestablished, and applying HSV color-space histogram cross matching method to evaluatingthe retrieved O/N2results from far ultraviolet remote sensing measurements. The resultsdemonstrate that OI130.4nm dayglow is suitable for remote sensing thermospheric O/N2,which will greatly reduce the difficulties of using far ultraviolet imaging spectrograph toremote sense the ionospheric state.Thirdly, the ionospheric Electron Density Profile is obtained from the limb-viewing OI135.6nm nightglow measurements of Global Ultraviolet Imager. In this paper, the limb-scanning viewing model is established, the computation of the projected matrix isderived, a free-form ionospheric Electron Density Profile is computed using theregularization method combined with Newton iteration, the Chapman-fitted ElectronDensity Profile is obtained by substitution of the peak altitude and peak electron density ofthe free-form ionospheric Electron Density Profile into the Chapman function, and comparethem with the corresponding results from the ground-based measurements and FullAnalytic Ionosphere Model, evaluating the effectiveness of the retrieval algorithm.Finally, the ionospheric Total Electron Content is inferred from the disk measurementsof OI135.6nm nightglow radiance intensity. The theoretical formulation betweennadir-viewing OI135.6nm nightglow radiance intensity and ionospheric Total ElectronContent is established, the radiometric correction of the measurements based onAtmospheric Ultraviolet Radiance Integrated Code is put forward, which serves as areference of using the disk-scanning OI135.6nm nightglow of far ultraviolet imagingspectrograph to monitor the ionospheric Total Electron Content. In this paper, theionospheric Total Electron Content retrieved from the disk and limb measurements of OI135.6nm nightglow radiation using three methods is computed, and the ionospheric TotalElectron Content of the same time and space using the neighboring linear interpolationmethod is used as the reference to evaluate the retrieved ionospheric Total ElectronContent.This paper focuses on both of the disk and limb viewing modes of space borne farultraviolet imaging spectrograph, leads the research of retrieving ionospheric environmentalparameters, such as O/N2, EDP and TEC, from the remote sensing data, and provides atheoretical basis and technical support for developing technology in future.更多还原