基于拉曼散射的海水盐度测量技术研究

发布时间：2018-10-25 07:26

【摘要】：海水盐度是海洋监测中的重要参数,对气象预报、渔业等生产生活领域乃至军事国防等重工业领域都有重要意义,对海水盐度的检测更是全面而深入地了解和运用海洋环境的基础。基于蓝绿激光散射的非接触式海水盐度遥感探测技术能够快速大面积测量海水盐度,具有结构完善,操作简便,性能稳定等优点,越来越受到学者们的重视。为了进一步发展完善的该盐度检测技术,实现对海水盐度测量系统的低成本、集成化,提出了基于拉曼散射的海水盐度测量技术研究该项课题。本研究基于激光拉曼光谱技术,建立激光拉曼散射海水盐度遥感系统,并展开了系统的优化改进、性能分析,之后通过大量室内配置溶液以及取样海水实验验证该系统的盐度测量精度和稳定性,为海水盐度的现场实时遥测技术的发展提供研究支持。首先,通过实验分析比较基于多种拉曼光谱特征海水盐度数据处理方法。采用MATLAB软件编写对应于不同方法的程序,之后使用该程序对测得的30种不同浓度的NaCl溶液拉曼光谱数据进行处理,最终比较各种拉曼光谱特征数据处理方法得到的实验结果,并选择测量较稳定且精确度相对高的对数面积比法和拉曼差异比法作为后期拉曼散射测盐系统的数据处理方法。其次,针对海水盐度的实时遥测问题,使用532nm固体激光器、卡塞格林望远镜、单色仪、像增强器、CCD等设计搭建基于532nm激光的拉曼散射海水盐度测量系统,该系统具有低成本、实用化的特点。并开发两种分别基于对数面积比法或者基于拉曼差异比法的LabVIEW软件操作系统,来实现对海水盐度的实时测量。该软件系统还采用时空累加算法有效增强了拉曼光谱信号的分辨能力和信噪对比度。并分别对对数面积比法和拉曼差异比法这两种拉曼散射海水盐度测量系统的性能进行了相应的探究。最后,在实验室分别测量了不同盐度水的拉曼散射光谱,分别建立对数面积比和拉曼差异比这两种光谱特征与海水盐度的线性关系,并应用得到的线性关系式对待测未知盐度溶液进行实时连续测量。并通过大量室内配置溶液和海水取样实验进一步确定该系统具有相对较高的盐度测量精度且在长时间工作时具有一定的系统稳定性。
[Abstract]:Seawater salinity is an important parameter in ocean monitoring. It is of great significance to meteorological forecast, fishery and other fields of production and life, as well as military and national defense and other heavy industrial fields. The detection of seawater salinity is the basis of comprehensive and deep understanding and application of marine environment. Non-contact remote sensing technique of seawater salinity based on blue-green laser scattering has been paid more and more attention to because of its advantages of perfect structure, simple operation, stable performance and so on. In order to further develop and improve the salinity measurement technology and realize the low cost and integration of seawater salinity measurement system, this paper puts forward the research topic of sea water salinity measurement technology based on Raman scattering. Based on laser Raman spectroscopy, a laser Raman scattering seawater salinity remote sensing system was established, and the system was optimized and improved, and the performance of the system was analyzed. After that, the accuracy and stability of the system are verified by a large number of indoor solutions and sea water sampling experiments, which provide research support for the development of real-time telemetry technology of seawater salinity. Firstly, the data processing methods of seawater salinity based on various Raman spectra are analyzed and compared. The program corresponding to different methods is written by MATLAB software, and then the Raman spectrum data of 30 different concentrations of NaCl solution are processed by the program. Finally, the experimental results obtained by various Raman spectrum characteristic data processing methods are compared. The logarithmic area ratio method and the Raman differential ratio method, which are relatively stable and accurate, are selected as the data processing methods for the later Raman scattering salt measurement system. Secondly, aiming at the real-time telemetry of seawater salinity, the 532nm solid-state laser, Cassegrain telescope, Monochromator, image intensifier and CCD are used to design and build a Raman scattering seawater salinity measurement system based on 532nm laser, which has low cost. The characteristics of pragmatism. Two kinds of LabVIEW software operating systems based on logarithmic area ratio method or Raman differential ratio method are developed to realize the real-time measurement of seawater salinity. The software system also improves the resolution ability and the signal noise contrast of Raman spectrum signal by space-time accumulation algorithm. The performance of the two Raman scattering seawater salinity measurement systems, logarithmic area ratio method and Raman differential ratio method, are investigated respectively. Finally, the Raman scattering spectra of different salinity water were measured in laboratory, and the linear relationship between the logarithmic area ratio and Raman difference ratio was established. The linear relation is used to measure the unknown salinity solution in real time and continuous measurement. Through a large number of indoor solution and sea water sampling experiments, it is further confirmed that the system has relatively high salinity measurement accuracy and has a certain system stability during long working hours.
【学位授予单位】：哈尔滨工业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：O657.37;P714.1

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