An airborne trace gas sensor based on mid-infrared technology is presented for fast (1 s) and high-precision ethane measurements during the Atmospheric Carbon and Transport-America (ACT-America) study. The ACT-America campaign is a multiyear effort to better understand and quantify sources and sinks for the two major greenhouse gases carbon dioxide and methane. Simultaneous airborne ethane and methane measurements provide one method by which sources of methane can be identified and quantified. The instrument described herein was operated on NASA's B200 King Air airplane spanning five separate field deployments. As this platform has limited payload capabilities, considerable effort was devoted to minimizing instrument weight and size without sacrificing airborne ethane measurement performance. This paper describes the numerous features designed to achieve these goals. Two of the key instrument features that were realized were autonomous instrument control with no onboard operator and the implementation of direct absorption spectroscopy based on fundamental first principles. We present airborne measurement performance for ethane based upon the precisions of zero air background measurements and ambient precision during quiescent stable periods. The airborne performance was improved with each successive deployment phase, and we summarize the major upgraded design features to achieve these improvements. During the fourth deployment phase in the spring of 2018, the instrument achieved 1 s (1σ) airborne ethane precisions reproducibly in the 30–40 parts per trillion by volume (pptv) range in both the boundary layer and the less turbulent free troposphere. This performance is among some of the best reported to date for fast (1 Hz) airborne ethane measurements. In both the laboratory conditions and at times during calm and level airborne operation, these precisions were as low as 15–20 pptv.

中文翻译：

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自主的机载中红外光谱仪，用于在NASA ACT-America研究期间进行乙烷的高精度测量

提出了一种基于中红外技术的机载微量气体传感器，用于在大气碳和美洲运输（ACT-America）研究期间进行快速（1 s）和高精度乙烷测量。ACT-America运动是一项多年努力，目的是更好地了解和量化两种主要温室气体二氧化碳和甲烷的来源和汇。空气中乙烷和甲烷的同时测量提供了一种可识别和量化甲烷来源的方法。本文所述的仪器是在NASA的B200 King Air飞机上操作的，该飞机横跨五个单独的现场部署。由于该平台的有效载荷能力有限，因此在不牺牲机载乙烷测量性能的前提下，已付出了巨大的努力来最小化仪器的重量和尺寸。本文介绍了旨在实现这些目标的众多功能。已实现的两个关键仪器功能是无机载操作员的自主仪器控制以及基于基本第一原理的直接吸收光谱法的实现。我们基于静态背景下零空气背景测量的精度和环境精度，介绍了乙烷的航空测量性能。在每个后续部署阶段，机载性能都会得到改善，我们总结了主要的升级设计功能，以实现这些改进。在2018年春季的第四个部署阶段，仪器达到1 s（1 已实现的两个关键仪器功能是无机载操作员的自主仪器控制以及基于基本第一原理的直接吸收光谱法的实现。我们基于静态背景下零空气背景测量的精度和环境精度，介绍了乙烷的航空测量性能。在每个后续部署阶段，机载性能都会得到改善，我们总结了主要的升级设计功能，以实现这些改进。在2018年春季的第四个部署阶段，仪器达到1 s（1 已实现的两个关键仪器功能是无机载操作员的自主仪器控制以及基于基本第一原理的直接吸收光谱法的实现。我们基于静态背景下零空气背景测量的精度和环境精度，介绍了乙烷的航空测量性能。在每个后续部署阶段，机载性能都会得到改善，我们总结了主要的升级设计功能，以实现这些改进。在2018年春季的第四个部署阶段，仪器达到1 s（1 我们基于静态背景下零空气背景测量的精度和环境精度，介绍了乙烷的航空测量性能。在每个后续部署阶段，机载性能都会得到改善，我们总结了主要的升级设计功能，以实现这些改进。在2018年春季的第四个部署阶段，仪器达到1 s（1 我们基于静态背景下零空气背景测量的精度和环境精度，介绍了乙烷的航空测量性能。在每个后续部署阶段，机载性能都会得到改善，我们总结了主要的升级设计功能，以实现这些改进。在2018年春季的第四个部署阶段，仪器达到1 s（1σ）边界层和湍流较少的自由对流层中，空运乙烷的精度可重复地在每兆体积30–40体积（pptv）范围内。该性能是迄今为止进行快速（1 Hz）机载乙烷测量的最佳报告之一。在实验室条件下以及在平静和水平空降操作时，这些精度都低至15–20 pptv。