The Methane Isotopologues by Solar Occultation (MISO) Nanosatellite Mission: Spectral Channel Optimization and Early Performance Analysis
The Methane Isotopologues by Solar Occultation (MISO) Nanosatellite Mission: Spectral Channel Optimization and Early Performance Analysis
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DOI：
10.3390/rs9101073
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发表时间：
2017-10
期刊：
影响因子：
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通讯作者：
D. Weidmann;A. Hoffmann;N. Macleod;K. Middleton;J. Kurtz;S. Barraclough;D. Griffin
中科院分区：
文献类型：
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作者：
D. Weidmann;A. Hoffmann;N. Macleod;K. Middleton;J. Kurtz;S. Barraclough;D. Griffin
MISO是一项在轨演示任务，其重点是改善整个对流层上层和平流层甲烷分布的表现，以补充和增强最低点和天顶观测甲烷观测系统，以便更好地了解甲烷预算。MISO还旨在通过演示适用于未来星座部署的纳米卫星平台上的甲烷多普勒限制大气透射率光谱，将激光外差光谱辐射测量（LHR）和相关小型化技术的概念提升到空间任务准备阶段。简要介绍了MISO的仪器和工程方法，以证明该任务的技术可行性。LHR使用窄光谱覆盖范围（<1 cm−1），专注于几个精心选择的单个反振动跃迁。建立了逐行光谱通道选择方法，并将其应用于热红外和短波红外LHR共登记甲烷同位素测深相关的光谱通道选择优化。然后使用其中一个选定的窗口进行基于测量噪声传播的甲烷回收的第一次性能分析。单次观测的初步分析表明，在海拔8-20公里范围内，理想的仪器精度<1%，在海拔20-30公里范围内<5%，在海拔37公里范围内<10%，这为现实世界的误差预算退化留下了很大的储备，预示着任务的可行性。MISO可以在多普勒有限光谱分辨率下真实地演示甲烷边缘探测，即使是在成本效益低的6 dm3纳米卫星上。
MISO is an in-orbit demonstration mission that focuses on improving the representation of the methane distribution throughout the upper troposphere and stratosphere, to complement and augment the nadir- and zenith-looking methane observing system for a better understanding of the methane budget. MISO also aims to raise to space mission readiness the concept of laser heterodyne spectro-radiometry (LHR) and associated miniaturization technologies, through demonstration of Doppler-limited atmospheric transmittance spectroscopy of methane from a nanosatellite platform suitable for future constellation deployment. The instrumental and engineering approach to MISO is briefly presented to demonstrate the technical feasibility of the mission. LHR operates using narrow spectral coverage (<1 cm−1) focusing on a few carefully chosen individual ro-vibrational transitions. A line-by-line spectral channel selection methodology is developed and used to optimize spectral channel selection relevant to methane isotopologue sounding from co-registered thermal infrared and short-wave infrared LHR. One of the selected windows is then used to carry out a first performance analysis of methane retrievals based on measurement noise propagation. This preliminary analysis of a single observation demonstrates an ideal instrumental precision of <1% for altitudes in the range 8–20 km, <5% for 20–30 km and <10% up to 37 km on a single isotopologue profile, which leaves a significant reserve for real-world error budget degradation and bodes well for the mission feasibility. MISO could realistically demonstrate methane limb sounding at Doppler-limited spectral resolution, even from a cost-effective 6 dm3 nanosatellite.