Miniature autonomous LHR for CO2 column measurements

全球大气中二氧化碳水平的上升和加速，很可能是由于人类活动和人为排放，被认为是气候变化的主要驱动因素。在全球碳生物地球化学循环中，陆地（在较小程度上，海洋）源、汇和反馈的区域量化仍然不确定，特别是在热带地区。同样，需要化石来源二氧化碳排放的地理格局来改进区域土地通量估算。减少碳循环量化的不确定性是当前气候研究中最具挑战性的任务之一。因此，迫切需要改进的仪器作为碳观测系统的一部分，要么产生超出目前商业系统能力的新数据集，要么参与下一代天基远程探测仪通量估计算法的验证和约束。我们提出了一种仪器概念的演示，预计将首次部署密集、自主的地面测深网络，用于大气CO2剖面和柱测量。超小型化热红外激光外差光谱辐射计（TIR-LHR）的概念具有显著的优势：高柱测量精度（90年代<0.5%），高时间分辨率（~1次测量/分钟），前所未有的紧凑和可部署的封装，最终适合作为大型网络的一部分自主运行，以及中等的购买和维护成本。我们相信，所提出的技术的好处使温室气体（GHG）测量和相关科学研究迈出了重要的质的一步。仪器概念结合了TIR-LHR的优点，以及我们开发的基于激光系统的最新小型化进展。尽管具有内在的灵活性，但该演示器将把二氧化碳（以及H2O和SF6）作为最重要的温室气体之一，其通量需要精确的表征和监测。

Globally rising and accelerating levels of CO2 in the atmosphere, most likely due to human activity and anthropogenic emissions , are believed to be the main driver of climate change . Within the global carbon biogeochemical cycle, the regional quantification of terrestrial (and to a lesser extent, oceanic) sources, sinks and feedbacks remains uncertain, particularly in the tropics . Likewise, geographical patterns of CO2 emissions from fossil sources are needed to improve upon the regional land flux estimates . Reducing uncertainties on the carbon cycle quantification is currently one of the most challenging tasks within climate research. Therefore improved instrumentation to be part of a carbon observing system is urgently needed, either to produce new dataset beyond what commercial systems are currently capable of, or to participate in the validation and constraining of flux estimation algorithms along the next generation of space-based remote sounders.We propose the demonstration of an instrument concept anticipated to enable for the first time the deployment of dense, autonomous, ground-based sounder networks for atmospheric CO2 profiling and column measurements. The concept of ultra-miniaturized thermal infrared laser heterodyne spectro-radiometer (TIR-LHR) offers significant advantages: high column measurement precision (<0.5% in 90s), high temporal resolution (~1 measurement/minute), unprecedented compact and deployable package ultimately suitable to operate autonomously as part of large networks, and moderate cost of purchase and maintenance. We believe the benefits of the proposed technology enable a significant qualitative step in greenhouse gas (GHG) measurement and associated scientific investigations. The instrument concept combines the benefits of TIR-LHR, and those of the latest miniaturization advances in laser based systems we have developed. Even though intrinsically flexible, the demonstrator will target CO2 (and H2O and SF6) as one of the most important GHG whose fluxes needs accurate characterization and monitoring.