机载积分路径差分吸收（IPDA）激光雷达测量大气CO2浓度研究
文献类型：学位论文
| 作者 | 史成龙 |
| 学位类别 | 硕士 |
| 答辩日期 | 2015 |
| 授予单位 | 中国科学院上海光学精密机械研究所 |
| 导师 | 陈卫标 |
| 关键词 | 二氧化碳浓度 光学差分吸收 机载IPDA激光雷达 测量误差 地面验证 |
| 其他题名 | Research on Air-borne IPDA Lidar carbon dioxide column concentrations measurement |
| 中文摘要 | 大气CO2是引起温室效应的主要气体之一，在全球气候变化中扮演重要作用。全球大气CO2浓度的精确测量，对于增强对碳循环的理解和气候气象研究重大帮助，有助于可靠的预测将来的CO2排放收支平衡，因此具有重要的科学意义和应用价值。为了更好地预测气候变化，制定有效的政治框架来约束温室气体的排放，需要一个更精确高效的全球大气温室气体检测技术。 光学差分吸收激光雷达技术是一种高精度、高灵敏度的测量方法，已被广泛应用于痕量气体浓度测量等多个领域。它作为一种有效的，高精度的测量手段，不易受太阳辐射、气溶胶散射、地域、季节的影响，是一个全新的应用技术。 本文首先简要介绍了机载积分路径差分吸收激光雷达(IPDA)激光雷达的研究背景和国内外相关动态。第二章介绍了机载差分吸收激光雷达的探测原理以及CO2浓度反演方法。第三章介绍了激光雷达工作波长选择与优化，在介绍了相关大气模型的基础后，着重讨论了大气温度和权重函数对波长选择的影响，给出了优化的工作波长，on-line波数为6361.2250cm-1，off-line波数为6360.979cm-1。 第四章对机载IPDA激光雷达测量CO2浓度误差进行了分析。对选定的on-line波长6361.2250cm-1进行浓度测量误差分析。主要分析了相对随机误差中的光子噪声、探测器噪声、散斑噪声和背景噪声等引入的误差和相对系统误差中的温度不确定度、压强不确定度、水汽浓度不确定度、激光器参数(带宽、频率漂移、光谱纯度)、脉冲能量监测误差、平台指向变化引入误差、差分吸收双波长足印不重叠引起的地表反射率剧烈变化等产生的误差，通过理论分析和仿真给出了各误差源引入的CO2浓度测量误差，从而评估出对它们对IPDA系统测量CO2浓度的影响。最后对各个误差项进行了合成，给出了机载IPDA系统总误差，总误差为0.78ppm。 第五章进行了机载激光雷达系统初步地面验证试验，结合地面气象设备，获得大气参数（温度、压强、水汽），利用得到的数据进行大气CO2浓度的反演。受限于系统的不稳定性和数据量太少的原因，结果显示与气体分析仪测量的CO2浓度有误差约8ppm。 |
| 英文摘要 | CO2 is one of the main atmospheric greenhouse gases, which plays an important role in global climate change. Global CO2 concentration with high precision measurements are important for understanding carbon cycle and improving the climate forecast model. They are useful for the prediction of future CO2 source and sink, which have important scientific and application values. In order to predict the change of climate system reasonably as well as helping to make political strategies on greenhouse gas emission, a more accurate and effective technique to measure global atmospheric greenhouse gas has been strongly required, especially for CO2. Differential absorption Lidar(DIAL) technique is a method for trace gas concentration measurement with high accuracy and sensitivity, which has been applied to many fields. It is almost free from solar radiance and aerosol scattering .So air-borne DIAL is a promising technique for CO2 column concentrations measurement. First, the background and development of air-borne integrated path differential absorption(IPDA) lidar is introduced. Then the principle of air-borne DIAL and the CO2 concentration inversion method are presented in the second chapter. The third chapter introduces the selection and optimization of the wavelength of the air-borne IPDA lidar. We discussed in detail the influence of temperature and weighting function for wavelength, and the optimized with on-line 6361.2250cm-1 and off-line 6360.979cm-1 are presented. In the fourth chapter, we analyze the CO2 concentration measurement errors of air-borne IPDA lidar . Relative random errors (RRE) and relative systematic errors (RSE) are studied at optimized wavelengths with given lidar system parameters. RRE arise from photon noise, detector noise, laser speckle noise and background noise. RSE arise from temperature uncertainty, pressure uncertainty, water vapor mixing ratio uncertainty, laser parameters (bandwidth, frequency drift and spectral purity) change, pulse energy calibration, pointing misalignment due to platform change and strongly varying surface reflectivity conditions due to overlap error. The CO2 concentration measurement errors from those error sources are analyzed through theoretical simulation. Under the assumptions of reasonable parameters uncertainties, the measurement errors were calculated and their influences on IPDA system performance were estimated. Finally, total absolute error budget of 0.78ppm is given from individual relative errors contributions. The preliminary experiment results of the air-borne lidar system are present in the fifth chapter. Combined with the parameters from the ground meteorological equipment, such as temperature, pressure, water vapor, we can retrieve CO2 column concentrations from the hard target echo signal about 824m away in horizontal direction. Because of the instability of the system few valid data is got, which is used to calculate CO2 concentrations. The lidar measured concentrations are almost lower 8ppm than concentrations from CO2 gas analyzer. |
| 语种 | 中文 |
| 源URL | [http://ir.siom.ac.cn/handle/181231/16886]  |
| 专题 | 上海光学精密机械研究所_学位论文 |
| 推荐引用方式 GB/T 7714 | 史成龙. 机载积分路径差分吸收（IPDA）激光雷达测量大气CO2浓度研究[D]. 中国科学院上海光学精密机械研究所. 2015. |
入库方式： OAI收割
来源：上海光学精密机械研究所
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