| 题名 | 云与气溶胶探测技术研究 |
| 作者 | 张子辉 |
| 学位类别 | 博士 |
| 答辩日期 | 2015-05 |
| 授予单位 | 中国科学院大学 |
| 导师 | 王淑荣 |
| 关键词 | 大气遥感 气溶胶 反远距 像方远心 像差渐晕 像面照度 辐亮度定标 |
| 其他题名 | The Study on Detection Technology of Cloud and Aerosol |
| 学位专业 | 光学工程 |
| 中文摘要 | 气溶胶是指大气中悬浮的直径在0.01 μm~100 µm范围内的固体和液体粒子，是大气三大活跃成分之一。气溶胶对气候、环境和遥感定量化都存在较大的影响，逐渐成为影响人类生存和社会发展的严重问题。实现大气气溶胶全球分布探测，对研究气溶胶反演和预测具有重大意义。无论是在时间尺度还是在空间尺度上，气溶胶的数量与种类的变化都非常巨大，造成大气气溶胶全球探测和反演十分困难。为实现全球尺度的气溶胶探测，采用卫星遥感作为气溶胶探测的手段。 卫星遥感探测气溶胶需要首先解决三个问题：一是有云区域的确定；二是地表反射噪声的剔除；三是大气分子散射的消除。通过对云、大气分子、地表和气溶胶等物质散射特点的分析，确定了能够有效进行云与气溶胶探测的六个波段（380 nm、410 nm、670 nm、865 nm、1610 nm和2200 nm）。 依照用户需求，设计一种结构紧凑，视场角为±36°，刈幅宽度为1000 km，地面分辨率优于1 km的广角成像光学系统。该光学系统选择负正透镜组分离（负光焦度透镜组作为前组，正光焦度透镜组作为后组）的反远距光学结构，可以同时满足广角和长工作距离的要求。考虑到滤光片的干涉原理，利用像方远心设计减少各视场主光线在滤光片上的入射角度，避免了像面上不同位置的光谱响应曲线出现较大差异，有利于气溶胶的高精度反演。采用像差渐晕法，增加离轴视场的渐晕系数，用于提高光学系统的像面照度均匀性。 根据光学系统的结构特点，开展了原理样机性能检测和定标实验研究。在装调过程中，重点解决了多光轴光学系统光轴调校的技术难题，通过实验验证，各通道光轴之间的夹角小于15″。此外，提出了一套既可用于线阵探测器焦面安装，又可用于畸变检测（几何定标）的通用型实验设备，角度监测误差小于5″，采用该检测方法检查出原理样机的畸变小于1.8%。应用传统方法对镜头和整机进行性能评价，镜头检测结果与设计结果吻合，整机测试结果达到指标要求。通过搭建高精度光谱定标装置，使样机光谱定标精度达到±0.017 nm，并得到样机的光谱响应曲线。经分析，各视场的光谱响应曲线的中心波长差异小于0.7 nm，验证了像方远心光路能够有效减少不同视场光谱响应差异的设计思想。根据大视场辐亮度定标的困难，采用分割视场法对原理样机进行辐亮度定标。对辐亮度定标结果进行计算，样机的像面照度均匀性达到84.5%，证明了像差渐晕法能够有效提高像面照度均匀性。 通过本文的研究，主要取得了以下几个方面的成果：得到广角低畸变气溶胶探测仪设计方案；有效解决了广角光学系统中消除光谱差异和提高像面照度均匀性两个问题；提出并验证了多光轴光学系统装调和检测的新方法；研制了一台各项指标均满足应用要求的云与气溶胶成像仪原理样机。同时，云与气溶胶探测仪的刈幅宽度和地面分辨率都远超国际同类仪器，为今后多谱段云与气溶胶成像仪研制奠定了技术基础。 |
| 英文摘要 | Atmospheric aerosol is solid or liquid particle whose diameter ranges from 0.01 μm to 100 μm, and is one of the three active ingredients suspended in the atmosphere. Atmospheric aerosol has a great effect on the climate, environment and remote sensing, are becoming more signifcant for human life and social evelopment. Due to the great variation of aerosol in the time scale and spatial scale, it is very difficult to detect and retrieve aerosol. In this thesis, satellite remote sensing is chosen to detect aerosol in the global scale. There are three key problems for aerosol detection: the first is determining the area of clouds; the second is removing the surface reflection of the earth; the third is removing the signal of atmospheric molecular scattering. By means of the analysis on the features of cloud scattering, aerosol scattering, atmospheric molecular scattering and surface reflection, we can determine six channels (380 nm, 410 nm, 670 nm, 865 nm, 1610 nm and 2200 nm) in the cloud and aerosol detector. Based on the users’requirements for aerosol detection, we designed a compact wide angle imaging system whose field of view is ±36° and the swath width is 1000 km with a ground resolution of 1000 m. This system takes the retrofocus optical structure which could meet the requirements of wide angle and long work distance at the same time. According to the interference principle of filter, telecentric structure is used to minimize the incidence angle of each chief ray on the filter, to avoid spectral response discrepancy at different field of angle, which is in favor of aerosol retrieval. The method of aberration vignetting is adopted to increase vignetting coefficient of off-axis field, which can improve the illuminance uniformity of the image plane. Based on configuration characteristics of the optical system, the test is made on the performance and calibration of the prototype. In the alignment process, a technical problem about alignment of optical axes parallelism in multi-optical system is solved and the accuracy of axis parallelism is up to 15". A focal plane array detector mounting device is designed, which can also be used to measure distortion and geometric calibration. By this method, the device's precision of angle monitoring is less than 5″, and the distortion of prototype is less than 1.8%. Through the performance evaluation of the lens and the prototype, the test results of the prototype are consistent with the design results, which can meet the design requirement. A high precision spectral calibrationtesting device is designed. The precision of spectral calibration for the prototype is ±0.017 nm. By analyses, the difference between spectral response curve of each field is equal to 0.7 nm, verifying that the telecentric design can decrease the wavelength difference of each field. Base on the difficulty of radicance calibration for wide-field imager, the field segmental radiance calibration method is made on the prototype. Depending on the result of radiance calibration, the illumination uniformity of the prototype reached 84.5%, verifying the aberration vignetting method can effectively improve the image plane illumination uniformity. The result of the study is outlined as follows: a wide-angle low distortion aerosol detector was designed; the two problems about removing spectral difference and improving illumination uniformity are effectively solved; a new method for alignment of optical axes parallelism in multi-optical system is put forward; a qualified cloud and aerosol prototype is developed. It provides the foundation in technology for the development of new generation multi-channel cloud and aerosol detector. |
| 公开日期 | 2015-12-24 |
| 内容类型 | 学位论文 |
| 源URL | [http://ir.ciomp.ac.cn/handle/181722/48957]  |
| 专题 | 长春光学精密机械与物理研究所_中科院长春光机所知识产出 |
| 推荐引用方式 GB/T 7714 | 张子辉. 云与气溶胶探测技术研究[D]. 中国科学院大学. 2015. |
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