相移光谱技术在气溶胶消光系数测量中的应用研究

发布时间：2018-01-19 12:35

本文关键词： 相移气溶胶消光系数光谱检测大气测量　出处：《浙江师范大学》2015年硕士论文　论文类型：学位论文

【摘要】：气溶胶对人类健康、大气气候、空气质量和生态等有着重大的影响,已经被认为是增加大气温室效应最大的“贡献”者之一。在多种影响气候变化的影响因子中,气溶胶的辐射强迫作用是最不确定的。然而气溶胶辐射强迫对分析大气的辐射平衡、化学过程、气候变化等有着重大科学意义。因此气溶胶辐射强迫测量一直是研究的热点。随着气溶胶辐射强迫对气候的影响研究的深入发展,精确测量气溶胶光学特性参数显得尤为重要。气溶胶光学特性参数恰恰是气溶胶气候模式研究中的关键,对于提高气候模式预报精度有着重要的意义。如气溶胶消光系数可作为反映大气能见度的衡量指标等。同时气溶胶消光系数与气溶胶辐射吸收、散射和单次反照率有着密切关系,因此准确测量气溶胶消光特性对了解气溶胶辐射强迫有着的重大科学意义。目前,测量大气气溶胶消光特性技术有：激光雷达技术、太阳光度计技术和脉冲腔衰荡光谱技术等。基于激光雷达技术测量,可以同时反演出气溶胶多种光学特性参数,但代价高,不适于常规测量、系统体积大、背景干扰大等。基于太阳光度计技术的测量,操作简单、系统体积小,但在阴天或下雨天无法正常测量、测量精度低。基于脉冲腔衰荡光谱技术测量,测量精度高,但所用激光器成本是LED光源成本的几千倍。为了解决上述测量方法存在的问题,提出本论文研究内容,即基于相移光谱技术测量大气气溶胶消光系数。相移光谱技术具有检测灵敏度高、光源便宜、有效吸收光程长等优点,因此相移光谱技术在实际应用过程中具有更加突出的优势,并且应用十分广泛,如镜片反射率测量、微量气体浓度测量、大气气溶胶消光系数测量等。相移光谱技术是通过测量探测信号与参考信号的相位差来反演气溶胶消光系数,与光源稳定性无关。在本文中,利用一阶传感理论,将光学谐振腔作为一阶传递系统,推导了腔衰荡光谱技术与相移光谱技术理论。同时理论模拟分析了消光系数测量技术指标等。进而设计了一个基于相移光谱技术测量大气气溶胶消光系数的系统。首先,将相移系统用对于测量腔镜反射率。其次将该测量系统用于对光学谐振腔损耗定性测量,同时对该系统进行稳定性测量,通过Allan方差分析,相移系统测量消光系数探测极限大小。最后,将相移系统用于实地大气气溶胶消光系数测量,并分析了消光系数与PM2.5的相关性。最后对全文进行总结,并提出一些展望。
[Abstract]:Aerosols have a significant impact on human health, atmospheric climate, air quality and ecology. It has been considered one of the biggest contributors to the increase in the atmosphere of Greenhouse Effect. Among the many factors that affect climate change. The radiative forcing of aerosols is the most uncertain. However, aerosol radiative forcing analyses the radiation balance and chemical processes of the atmosphere. Therefore, aerosol radiative forcing measurement has been a hot research topic. With the development of aerosol radiation forcing on climate, the influence of aerosol radiation forcing on climate has been developed. It is very important to accurately measure the aerosol optical properties, which is the key to the study of aerosol climate model. It is of great significance to improve the prediction accuracy of climate model, such as aerosol extinction coefficient, which can be used as a measure index to reflect atmospheric visibility, and aerosol extinction coefficient and aerosol radiation absorption. Scattering is closely related to single albedo, so it is of great scientific significance to accurately measure aerosol extinction characteristics to understand aerosol radiative forcing. The measurement of atmospheric aerosol extinction is based on lidar, solar photometer, pulse cavity ring-down spectroscopy and so on. Aerosol optical parameters can be inversed at the same time, but the cost is high, it is not suitable for conventional measurement, the system volume is large, the background interference is large. The measurement based on the solar photometer technology is simple to operate and the system volume is small. However, it can not be measured normally in cloudy or rainy days, and the measurement accuracy is low. Based on the pulse cavity ring-down spectrum technology, the measurement accuracy is high. However, the cost of the laser is several thousand times that of the LED light source. In order to solve the problems of the above measurement methods, the research content of this paper is put forward. That is to measure the extinction coefficient of atmospheric aerosol based on phase shift spectrum technology which has the advantages of high detection sensitivity cheap light source and long effective absorption path. Therefore, phase shift spectroscopy has more outstanding advantages in practical applications, and is widely used, such as lens reflectivity measurement, trace gas concentration measurement. The phase shift spectrum technique is to measure the phase difference between the detection signal and the reference signal to retrieve the aerosol extinction coefficient, which has nothing to do with the stability of the light source. Using the first order sensing theory, the optical resonator is regarded as the first order transfer system. The theory of cavity ring-down spectroscopy and phase-shift spectroscopy is derived. At the same time, the measurement technical index of extinction coefficient is simulated and analyzed. Furthermore, a system for measuring atmospheric aerosol extinction coefficient based on phase-shift spectroscopy is designed. First. The phase-shifting system is used to measure mirror reflectivity. Secondly, the measurement system is used to measure the optical resonator loss qualitatively, and the stability of the system is measured by Allan variance analysis. Finally, the phase shifting system is used to measure the extinction coefficient of atmospheric aerosol in the field, and the correlation between extinction coefficient and PM2.5 is analyzed. Finally, the full text is summarized. Some prospects are put forward.
【学位授予单位】：浙江师范大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：X831

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