Methane retrieval from MethaneAIR using the CO 2 proxy approach: a demonstration for the upcoming MethaneSAT mission

作者：Christopher Chan Miller, Sébastien Roche, Jonas Wilzewski, Xiong Liu, K. Chance, Amir H. Souri, E. K. Conway, Bingkun Luo, Jenna Samra, J. Barry Hawthorne, Kang Sun, Carly Staebell, Apisada Chulakadabba, Maryann Sargent, Joshua Benmergui, Jonathan E. Franklin, Bruce C. Daube, Yang Li, Joshua L. Laughner, Bianca C. Baier, Ritesh Gautam, Mark Omara, Steven C. Wofsy · 发表于：Atmospheric measurement techniques · 年份：2024 · DOI：10.5194/amt-17-5429-2024 · 被引用次数：42 · 研究领域：Atmospheric and Environmental Gas Dynamics、Hydrocarbon exploration and reservoir analysis、Methane Hydrates and Related Phenomena

Abstract. Reducing methane (CH4) emissions from the oil and gas (O&G) sector is crucial for mitigating climate change in the near term. MethaneSAT is an upcoming satellite mission designed to monitor basin-wide O&G emissions globally, providing estimates of emission rates and helping identify the underlying processes leading to methane release in the atmosphere. MethaneSAT data will support advocacy and policy efforts by helping to track methane reduction commitments and targets set by countries and industries. Here, we introduce a CH4 retrieval algorithm for MethaneSAT based on the CO2 proxy method. We apply the algorithm to observations from the maiden campaign of MethaneAIR, an airborne precursor to the satellite that has similar instrument specifications. The campaign was conducted during winter 2019 and summer 2021 over three major US oil and gas basins. Analysis of MethaneAIR data shows that measurement precision is typically better than 2 % at a 20×20 m2 pixel resolution, exhibiting no strong dependence on geophysical variables, e.g., surface reflectance. We show that detector focus drifts over the course of each flight, likely due to thermal gradients that develop across the optical bench. The impacts of this drift on retrieved CH4 can mostly be mitigated by including a parameter that squeezes the laboratory-derived, tabulated instrument spectral response function (ISRF) in the spectral fit. Validation against coincident EM27/SUN retrievals shows that ...