Atmospheric Trace Gas Flux Meter Using Tunable Diode Lasers

使用可调谐二极管激光器的大气痕量气体通量计

• 批准号: 8760686
• 负责人: Mark Zahniser
• 金额: $ 5万
• 依托单位: Aerodyne Research Inc
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 1988
• 资助国家: 美国
• 起止时间: 1988-01-01 至 1988-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=8760686&HistoricalAwards=false
• 关键词: Atmospheric; Trace; Gas; Flux; Meter

The chemical composition of the troposphere is determined by the sources and sinks of biogenic and anthropogenic trace gases and the intervening photochemical transformations and mass transport processes linking them. The recent recognition that a thorough understanding of these processes in the natural atmosphere is necessary before the effects of man-made perturbations may be assessed has prompted a concerted effort to study the natural troposphere. The insight gained from this research will allow more accurate predictions of the impact of man's activities on the environment. The objective of this Phase I SBIR research project is the development of instrumentation to measure fluxes of atmospheric trace gases to or from the earth's surface. The method to be investigated is based on the well established eddy correlation technique and would use a tunable diode laser light source combined with a multiple pass absorption cell to detect trace species at sub-part-per-billion levels. The instrument would be designed specifically to be interfaced with a sonic anemometer to provide fast time response and minimal flowfield interference as required for the eddy correlation method. In the Phase I study, designs for a reduced pressure trace gas sampling system are to be evaluated and tested, and a multiple pass absorption cell which maximizes the path length and minimizes interference fringes will be designed and evaluated. The results of the Phase I effort are expected to resolve critical design issues and permit the development of field instrumentation in succeeding phases. The final instrument will be applicable to flux measurements of trace gases including sulfur dioxide, nitric oxide, nitrogen dioxide, nitric acid, ozone, and hydrogen peroxide.

对流层的化学组成是由生物和人为微量气体的源和汇以及其间的光化学转化和将它们联系起来的质量传输过程决定的。最近认识到，在评估人为扰动的影响之前，必须彻底了解自然大气中的这些过程，这促使人们共同努力研究自然对流层。从这项研究中获得的见解将使我们能够更准确地预测人类活动对环境的影响。第一阶段SBIR研究项目的目标是研制仪器，以测量进出地球表面的大气微量气体的通量。要研究的方法是基于完善的涡流相关技术，并将使用可调谐二极管激光光源与多通道吸收细胞相结合，以检测十亿分之一的痕量物种。该仪器将被专门设计为与声波风速计接口，以提供快速的时间响应和最小的流场干扰，这是涡流相关方法所要求的。在第一阶段的研究中，将对减压微量气体取样系统的设计进行评估和测试，并设计和评估可最大化路径长度并最小化干涉条纹的多通道吸收池。第一阶段工作的结果有望解决关键的设计问题，并允许在后续阶段开发现场仪器。最终仪器将适用于微量气体的通量测量，包括二氧化硫、一氧化氮、二氧化氮、硝酸、臭氧和过氧化氢。