BIOCOMPLEXITY: High-Precision 13CO2/12CO2 Ratio Measurements Using an Optical Fiber Based Difference Frequency Generation Laser Source

该项目需要开发、测试、验证和部署基于中红外激光的气体传感器系统，用于连续原位测量大气中二氧化碳的同位素组成（13CO2/12CO2比），精度等于或优于0.1 / mil。来自国家大气研究中心、莱斯大学和科罗拉多大学的科学团队将利用最新的光纤技术发展。差频产生（DFG）的最新进展，以及多年来碳循环研究的经验。拟议的DFG仪器将采用在室温下工作的市售电信激光器。与传统的激光系统相比，这种激光源在实现高测量精度方面具有显著的优势。该仪器将用于获得13CO2/12CO2比例的高精度大气测量-目前通过烧瓶样品网络进行质谱分析来完成测量。这些数据对于了解陆地和海洋碳汇至关重要，这需要了解区域和地方二氧化碳源和汇过程的分布、贡献和演变。尽管同位素精度低于烧瓶法（0.012 / mil），但需要高精度连续测量以提供广泛的时间和空间覆盖范围，目前还没有一种可靠的现场可部署仪器，能够以0.1 / mil或更高的精度连续测量13CO2/12CO2，并具有可验证的准确性。这项工作的第一阶段将侧重于广泛的实验室测试，以确定和实施最佳实验条件以及数据采集和检索程序。下一阶段将重点放在现场测量的最佳包装上，随后将在科罗拉多大学Niwot Ridge天文台现场与最先进的烧瓶样品/质谱测量进行广泛的并排比较。同时测量将在地面和科罗拉多大学塔的设施上进行。新的连续测量将为Niwot Ridge站点的长期数据库提供基础，并为进一步将这些新测量扩展到其他场地和平台提供必要的经验。该项目在碳循环研究领域具有潜在的广泛影响。此外，新仪器和相关的新方法可以适应其他需要超高测量精度的新研究问题。此外，一个面向研究生和本科生、高中生和教师的多方面教育项目，将把这种新的激光和光纤技术的理解和使用转移到更广泛的科学界。本课程将向学生介绍：1)光纤技术的潜力及其应用；2)碳循环概述；3)高精度CO2同位素比测量所面临的挑战和提供的信息量。

This project entails the development, test, validation, and deployment of a mid-infrared laser based gas sensor system for continuous in-situ measurements of the isotopic composition of atmospheric carbon dioxide (13CO2/12CO2 ratio) with a precision equal to or better than 0.1 per mil. A science team from the National Center for Atmospheric Research, Rice University, and the University of Colorado will utilize the latest developments in optical fiber technology, recent advances in difference frequency generation (DFG), and multi-year experience in carbon cycle research. The proposed DFG instrument will employ commercially available telecommunication lasers which operate at room temperature. Such a laser source presents significant advantages over more traditional laser systems for achieving high measurement precision.The instrument will be used to acquire high precision atmospheric measurements of 13CO2/12CO2 ratios - a measurement currently accomplished by a network of flask samples followed by mass spectrometric analysis. These data are crucial for understanding terrestrial and oceanic carbon sinks which requires an understanding of the distribution, contribution, and evolution of regional and local CO2 source and sink processes. High precision continuous measurements are needed to provide broad temporal and spatial coverage, even though the isotopic precision is inferior to the flask method (0.012 per mil) At present there does not exist a robust field-deployable instrument capable of continuous 13CO2/12CO2 measurements with a precision of 0.1 per mil or better with verifiable accuracy.The first phase of this effort will focus on extensive laboratory testing to identify and implement optimal experimental conditions and data acquisition and retrieval routines. The next phase will focus on optimal packaging for field measurements, and this will be followed by an extensive set of side-by-side comparisons with state-of-the-art flask sample/mass spectrometric measurements carried out in the field at the University of Colorado's Niwot Ridge Observatory site. Co-located measurements will be carried out on both the ground and the University of Colorado tower facility. The new continuous measurements will provide the foundation for a long-term database from the Niwot Ridge site as well as the necessary experience to further extend these new measurements to other venues and platforms. This project has potential broad impacts in the area of carbon cycle research. In addition, the new instrument and associated new approaches can be adapted to other new research problems requiring ultra high measurement precision. Moreover, a multifaceted educational program with graduate and undergraduate students, high school students and teachers, will transfer the understanding and use of this new laser and fiber optic technology to a broader scientific community. The students will be introduced to 1) the potential of optical fiber technologies and its applications; 2) an overview of the carbon cycle; and 3) the challenges of, and information content offered by, high precision isotopic ratio measurements of CO2.