Development of a Gas Correlation Camera for Improved Ground-Based Monitoring of Volcanic SO2 Emissions

0321869 Watson这笔赠款支持轻量化(约3公斤)的开发和现场测试用于测量火山气羽流中二氧化硫的便携式气体相关相机。这款相机将基于Apogee AP8P数码相机，配备1024 x 1024电荷耦合器件(CCD)探测器，配备100 mm焦距镜头和带通滤光片，以选择在具有较强SO2吸收带(318 Nm)的波长下的紫外线辐射，并保持在铝制外壳中，这将使滤轮机构能够通过镜头前方已知浓度的SO2的气室。通过已知SO2浓度的参照池拍摄的图像与没有SO2的空白参照室之间的差异与视线SO2负荷成正比。Ccd阵列设计将促进大片羽流的空间测绘，运行定制软件的相关现场手提电脑将能够对数据进行近乎实时的解释和可视化。该仪器将在实验室进行校准，然后在蒙大拿州的一家燃煤发电厂进行测试，该发电厂独立记录烟囱污水中的二氧化硫浓度。这些测试将尝试验证实验室校准并评估仪器的检测下限。典型的燃煤电厂流出物的二氧化硫通量往往比典型的火山气体少一个数量级(例如，分别为25-100吨/天和200-1000吨/天)。该仪器还将在蒙特塞拉特的苏弗里尔山活火山进行测试，那里已经存在监测火山羽流中二氧化硫的独立技术(即COSPEC和DOAS)。近实时准确成像大气中二氧化硫的动态和准确估计二氧化硫通量的能力是火山学和大气化学研究的迫切需要，也是工业环境监测中潜在的有用工具。该仪器的开发和测试将涉及密歇根理工大学的一名研究生和教职员工，以及与NASA喷气推进实验室和蒙特塞拉特火山天文台的科学家合作。***

0321869WatsonThis grant supports the development and field testing of a lightweight (ca. 3 kg.) portable gas correlation camera for the measurement of SO2 in volcanic gas plumes. The camera will be based on an Apogee AP8P digital camera with a 1024 x 1024 charge coupled device (CCD) detector, fitted with a 100 mm focal length lens and bandpass filter to select for UV radiation at a wavelength that has a strong SO2 absorption band (318 nm), ad maintained in an aluminum housing which would allow a filter wheel mechanism to pass gas cells with known concentrations of SO2 in front of the lens. The difference between an image shot through a reference cell of know SO2 concentration and a blank reference cell with no SO2 is proportional to the line-of-sight SO2 burden. The CCD array design will facilitate spatial mapping of large areas of plumes and an associated field laptop running customized software will allow for near real-time interpretation and visualization of the data. The instrument will be laboratory calibrated and then tested at a coal-fired power plant in Montana that independently records SO2 concentrations in their smokestack effluent. These tests will attempt to validate laboratory calibrations and asses the detection limits of the instrument. Typical coal-fired power plant effluents have SO2 fluxes that are often an order of magnitude less than typical volcanic gases (e.g., 25-100 tonnes/d vs. 200-1000 tonnes/d, respectively). The instrument will also be tested at the active Soufriere Hills volcano on Montserrat where independent techniques for monitoring SO2 in the volcanic plume already exist (i.e., COSPEC and DOAS). The ability to accurately image the dynamics of SO2 in the atmosphere in near real-time and to accurately estimate SO2 fluxes is a critical need in volcanological and atmospheric chemistry research and a potentially useful tool in industrial environmental monitoring. The development and testing of this instrument will involve a graduate student and faculty at Michigan Technological University and collaborations with scientists at NASA-JPL and the Montserrat Volcanological Observatory. ***