MethaneAIR: Airborne Imaging Spectrometer Level 2 Ungridded Data. Version 1.0

IMPORTANT NOTE: As of 30 September 2024, the PI has asked that this dataset be hidden/removed from the archive. Users should contact Steve Wofsy (Harvard) for the latest version of the data. The data in the EOL archive is *not* the latest version and the PI will manage all versions of this dataset. MethaneAIR (“MAIR”) is a dual imaging spectrometer observing reflected sunlight at 1.65 µm (CH4 and CO2) and 1.27 µm. It measures absorption spectra with high spectral resolution, fine spatial resolution, wide swath, and high signal-to-noise ratio, enabling high-contrast, fine-grained images of CH4 column mean dry mole fraction. MAIR duplicates the spectroscopy of the upcoming MethaneSAT satellite (“MSAT”, launch Q1 2023). Development of the MAIR sensor and associated retrieval algorithms was supported by MethaneSAT LLC (a subsidiary of the Environmental Defense Fund). In 2019, NSF supported science demonstration flights of MAIR with an EAGER grant, carried out in August 2021 on the NCAR Gulfstream V. Two engineering test flights in Nov. 2019 (TF01, TF02) were successful, but the flight series was terminated due to avionics failures on the GV. The series was rescheduled for March 2020, but the US shut down that month due to COVID-19. Flights rescheduled for June 2021 were pushed to late July/August of 2021 to accommodate another mission that had been displaced by unavailability of the C-130. After a short test flight (TF03), research flights RF04-RF09 targeted oil and gas infrastructure in Texas, New Mexico, and North Dakota. There were also 21 flight segments on RF04 and RF05 to compare emission rates of methane derived from MethaneAIR data to controlled releases carried out near Odesa, TX, by the Stanford group of Adam Brandt. Engineering test flight TF10 was carried out at the end of the flight series. The spectrometer was inverted to view the upward-looking port of the G-V, recording the spatial pattern of airglow in the 1.27 µm band. This is a large dataset. Please only order the flights needed. See the readme for more information.