Runge Ethan, Langille Jeff, Schentag Connor, Bourassa Adam, Letros Daniel, Loewen Paul, Lloyd Nick, Degenstein Doug, Grandmont Frederick
Institute of Space and Atmospheric Studies, University of Saskatchewan, Saskatoon, Saskatchewan S7N 5E2, Canada.
Space and Defense Systems, ABB Canada, Québec, Quebec G1P 0B2, Canada.
Rev Sci Instrum. 2021 Sep 1;92(9):094502. doi: 10.1063/5.0060125.
The upper troposphere and lower stratosphere (UTLS) region is a highly variable region of the atmosphere and critical for understanding climate. Yet, it remains undersampled in the observational satellite record. Due to recent advances in interferometer and infrared detection technologies, imaging Fourier transform spectrometer (FTS) technology has been identified as a feasible remote sensing approach to obtain the required precision and spatial resolution of atmospheric trace gas composition in the UTLS. Building on the success of instruments such as the Michelson Interferometer for Passive Atmospheric Sounding and gimbaled limb observer for radiance imaging of the atmosphere, the limb imaging Fourier transform spectrometer experiment (LIFE) instrument, of which this paper details the design and performance, is a balloon-borne infrared imaging FTS developed as an early prototype of a low earth orbit satellite instrument. LIFE is constructed primarily with commercially available off-the-shelf components, with a design emphasis on greatly reducing the complexity of the instrument, particularly the cooling requirements, with a minimal reduction in information gain on the target atmospheric greenhouse gases of water vapor, methane, ozone, and nitrous oxide. The developed instrument was characterized through a series of thermal and vacuum tests and validated through a successful demonstration balloon flight during the 2019 Strato-Science campaign in Canada. In the calibration of the data from the balloon flight, an issue was identified regarding a lack of knowledge in the emissivity of the on-board blackbody calibration sources. These systematic effects were minimized through the application of an emissivity ratio determined from the characterization tests where a wider range of known blackbody temperatures were available. Despite this identified calibration issue, the results demonstrate that the instrument is capable of meeting primary performance requirements for trace gas retrievals of the target atmospheric species.
对流层上部和平流层下部（UTLS）区域是大气中一个高度多变的区域，对于理解气候至关重要。然而，在观测卫星记录中，该区域的采样仍然不足。由于干涉仪和红外探测技术的最新进展，成像傅里叶变换光谱仪（FTS）技术已被确定为一种可行的遥感方法，可用于获取UTLS中大气痕量气体成分所需的精度和空间分辨率。基于迈克尔逊被动大气探测干涉仪和用于大气辐射成像的万向节式边缘观测器等仪器的成功经验，本文详细介绍了设计和性能的边缘成像傅里叶变换光谱仪实验（LIFE）仪器，是一种作为低地球轨道卫星仪器早期原型开发的气球搭载式红外成像FTS。LIFE主要由商用现货组件构成，设计重点是大幅降低仪器的复杂性，特别是冷却要求，同时在目标大气温室气体水汽、甲烷、臭氧和一氧化二氮的信息获取上仅有最小程度的减少。所开发的仪器通过一系列热测试和真空测试进行了特性表征，并在2019年加拿大平流层科学活动期间通过一次成功的示范气球飞行进行了验证。在对气球飞行数据的校准中，发现了一个关于车载黑体校准源发射率知识不足的问题。通过应用从表征测试确定的发射率比，将这些系统效应降至最低，在表征测试中可获得更广泛范围的已知黑体温度。尽管存在这个已确定的校准问题，但结果表明该仪器能够满足目标大气物种痕量气体反演的主要性能要求。
