Atmospheric Trace Gas Flux Meter Using Tunable Diode Lasers

对流层的化学成分是 由生物源和人类活动的源和汇决定 痕量气体和介入的光化学转化， 将它们连接起来的物质运输过程。 最近承认 对自然界中这些过程的透彻理解 在人为影响之前， 扰动可能会被评估，促使协调一致的努力， 研究自然对流层。 从中获得的见解 研究将使人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 发展测量大气通量的仪器 地球表面的痕量气体 什么方法 研究是基于建立涡相关 技术，并将使用可调谐二极管激光光源 与多程吸收池相结合， 十亿分之几的物种。 该工具将是 专门设计用于与声波风速计连接， 提供快速响应和最小流场干扰， 这是涡动相关法所要求的。 在I期研究中， 减压痕量气体取样系统的设计 进行评估和测试，以及多程吸收池 其最大化路径长度并最小化干扰 条纹将被设计和评估。 该阶段的结果 我的工作是解决关键的设计问题， 允许开发现场仪表， 阶段。 最后的仪器将适用于通量 痕量气体的测量，包括二氧化硫、硝酸 氧化物、二氧化氮、硝酸、臭氧和氢气 过氧化物

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.