MethaneAIR L3 Concentration v1

This dataset provides geospatial data for the total column dry air mole fraction of methane in the atmosphere, "XCH4", as observed by the MethaneAIR imaging spectrometer. XCH4 is defined as the total column amount (number of molecules) of methane ("CH4") divided by the total amount of air (number of molecules, water vapor amount removed) along the line of sight from the airborne spectrometer to the earth's surface and back up to the sun. Additional data layers are provided for reference: observed albedo at 1622 nm, surface pressure, and terrain height.

Methane is a potent greenhouse gas that has more than 80 times the warming power of carbon dioxide over the first 20 years after it reaches the atmosphere. At least 30% of today's global warming is driven by methane from human actions. Cutting methane emissions associated with human activities - including avoidable emissions from oil and gas operations, agriculture, and waste management - is the single fastest way to slow the rate of global warming.

The aircraft was flown at 11.5 - 13 km altitude (37,000 - 43,000 feet), acquiring 10 frames per second with a swath of 4.5 - 4.8 km with a 25 degree field of view and 896 pixels across track, giving a native pixel size at nadir of approximately 25m along track and 5 m across track. The spectroscopic data are aggregated by 5 across track, giving a mean pixel size of 25m x 25m. Concentrations (XCH4) are retrieved from these high resolution (0.1 nm sampling, 0.3nm resolution), spatially distributed spectra (Chan Miller et al. (2024)), then gridded on a 0.0001 x 0.0001 degree grid (approximately 10m x 8m over the US). The precision of the gridded data is approximately 25 parts per billion (1s, about 1.3%), and a spatial correlation length (1/e) of about 70m. There are some variations from flight-to-flight according to operating conditions, look angle and surface albedo.

The flight pattern was typically a series of oval swaths in a Zamboni pattern to cover a region, typically about 70 km x 100 km, over a 2 - 3 hour interval. The data presented here are averaged where flight tracks overlap, typically at the edges of each swath and in the urns at the top and bottom of the Zamboni pattern.

This dataset was generated using MethaneAIR measurements taken on flights between 30 July 2021 and 13 October 2023. MethaneAIR is an airborne precursor of the MethaneSAT satellite mission, managed by MethaneSAT LLC, a wholly owned subsidiary of Environmental Defense Fund. Methane emission fluxes were produced using a geostatistical inverse modeling framework on each of these Zamboni swaths.

For additional information about the MethaneAIR instrument, instrument calibration and emission detections, please refer to recent publications by Loughner et al. (2021), Staebell et al. (2021), Conway et al. (2023), Chulakadabba et al. (2023), Abbadi et al. (2023), Omara et al. (2023), and Miller et al. (2023).

Contact the data provider for more information about the project at this link: https://www.methanesat.org/contact/