Chan Miller, C.、Roche, S.、Wilzewski, J. S.、Liu, X.、Chance, K.、Souri,
A. H. Conway, E.、Luo, B.、Samra, J.、Hawthorne, J.、Sun, K.、Staebell, C.、
Chulakadabba, A.、Sargent, M.、Benmergui, J. S.、Franklin, J. E.、Daube, B.
C. Li, Y.、Laughner, J. L. Baier, B. C. Gautam, R.、Omara, M., and Wofsy,
S. C. 2023 年。使用 CO2 Proxy Approach 從 MethaneAIR 擷取甲烷：
即將推出的 MethaneSAT 任務示範，EGUsphere [預先發布]。
doi:10.5194/egusphere-2023-19623
[null,null,[],[[["\u003cp\u003eThe EDF/MethaneSAT/MethaneAIR/L3concentration 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.\u003c/p\u003e\n"],["\u003cp\u003eMethaneAIR is an airborne precursor to the MethaneSAT satellite mission, flown at high altitudes to acquire atmospheric methane data with a spatial resolution of approximately 25m x 25m.\u003c/p\u003e\n"],["\u003cp\u003eThe dataset covers the period from July 30, 2021, to October 13, 2023, and includes data layers for XCH4, observed albedo, surface pressure, and terrain height.\u003c/p\u003e\n"],["\u003cp\u003eData is provided by the Environmental Defense Fund and is subject to the MethaneSAT Content License Terms of Use.\u003c/p\u003e\n"],["\u003cp\u003eUsers can explore this dataset and analyze it further using Google Earth Engine.\u003c/p\u003e\n"]]],["The dataset from Environmental Defense Fund's MethaneSAT provides \"XCH4,\" the atmospheric methane concentration, captured by the MethaneAIR spectrometer between August 6, 2021, and October 14, 2023. Data, gridded to approximately 10m x 8m resolution, also include observed albedo, surface pressure, and terrain height. Flights were conducted at high altitudes, using a Zamboni pattern to cover large areas, and data from overlapping tracks are averaged. The data can be accessed using Earth Engine, providing code examples for visualization and analysis.\n"],null,["# MethaneAIR L3 Concentration v1\n\nDataset Availability\n: 2021-08-06T00:00:00Z--2023-10-14T00:00:00Z\n\nDataset Provider\n:\n\n\n [Environmental Defense Fund - MethaneSAT](https://methanesat.org)\n\nTags\n:\n[atmosphere](/earth-engine/datasets/tags/atmosphere) [climate](/earth-engine/datasets/tags/climate) [edf](/earth-engine/datasets/tags/edf) [emissions](/earth-engine/datasets/tags/emissions) [ghg](/earth-engine/datasets/tags/ghg) [methane](/earth-engine/datasets/tags/methane) [methaneair](/earth-engine/datasets/tags/methaneair) [methanesat](/earth-engine/datasets/tags/methanesat) \n\n#### Description\n\nThis dataset provides geospatial data for the total column dry air mole\nfraction of methane in the atmosphere, \"XCH4\", as observed by the MethaneAIR\nimaging spectrometer. XCH4 is defined as the total column amount (number of\nmolecules) of methane (\"CH4\") divided by the total amount of air (number of\nmolecules, water vapor amount removed) along the line of sight from the\nairborne spectrometer to the earth's surface and back up to the sun.\nAdditional data layers are provided for reference: observed albedo at 1622\nnm, surface pressure, and terrain height.\n\nMethane is a potent greenhouse gas that has more than 80 times the warming power\nof carbon dioxide over the first 20 years after it reaches the atmosphere. At\nleast 30% of today's global warming is driven by methane from human actions.\nCutting methane emissions associated with human activities - including avoidable\nemissions from oil and gas operations, agriculture, and waste management - is\nthe single fastest way to slow the rate of global warming.\n\nThe aircraft was flown at 11.5 - 13 km altitude (37,000 - 43,000 feet),\nacquiring 10 frames per second with a swath of 4.5 - 4.8 km with a 25 degree\nfield of view and 896 pixels across track, giving a native pixel size at\nnadir of approximately 25m along track and 5 m across track. The\nspectroscopic data are aggregated by 5 across track, giving a mean pixel\nsize of 25m x 25m. Concentrations (XCH4) are retrieved from these high\nresolution (0.1 nm sampling, 0.3nm resolution), spatially distributed\nspectra ([Chan Miller et al. (2024)](https://doi.org/10.5194/egusphere-2023-1962)),\nthen gridded on a 0.0001 x 0.0001 degree grid (approximately 10m x 8m over\nthe US). The precision of the gridded data is approximately 25 parts per\nbillion (1s, about 1.3%), and a spatial correlation length (1/e) of about\n70m. There are some variations from flight-to-flight according to operating\nconditions, look angle and surface albedo.\n\nThe flight pattern was typically a series of oval swaths in a Zamboni\npattern to cover a region, typically about 70 km x 100 km, over a 2 - 3 hour\ninterval. The data presented here are averaged where flight tracks overlap,\ntypically at the edges of each swath and in the urns at the top and bottom\nof the Zamboni pattern.\n\nThis dataset was generated using MethaneAIR measurements taken on flights\nbetween 30 July 2021 and 13 October 2023. MethaneAIR is an airborne precursor of\nthe MethaneSAT satellite mission, managed by [MethaneSAT LLC](https://www.methanesat.org/),\na wholly owned subsidiary of Environmental Defense Fund. Methane emission fluxes were produced using a geostatistical inverse\nmodeling framework on each of these Zamboni swaths.\n\nFor additional information about the MethaneAIR instrument, instrument\ncalibration and emission detections, please refer to recent publications by\n[Loughner et al. (2021)](https://doi.org/10.1175/JAMC-D-20-0158.1),\n[Staebell et al. (2021)](https://doi.org/10.5194/amt-14-3737-2021),\n[Conway et al. (2023)](https://doi.org/10.5194/amt-2023-111),\n[Chulakadabba et al. (2023)](https://doi.org/10.5194/egusphere-2023-822),\n[Abbadi et al. (2023)](https://doi.org/10.31223/X51D4C),\n[Omara et al. (2023)](https://doi.org/10.5194/essd-15-3761-2023),\nand [Miller et al. (2023)](https://doi.org/10.5194/egusphere-2023-1962).\n\nContact the data provider for more information about the project at this\nlink: \u003chttps://www.methanesat.org/contact/\u003e\n\n### Bands\n\n\n**Pixel Size**\n\n10.2 meters\n\n**Bands**\n\n| Name | Units | Min | Max | Pixel Size | Description |\n|--------------------|-------|----------|-----------|------------|---------------------------------------------------------------------------|\n| `XCH4` | ppb | 1894\\* | 2114.65\\* | meters | Retrieved column-averaged dry-air CH4 mole fraction. |\n| `albedo` | | 0 | 1 | meters | Ratio of solar radiance at the ground to observed radiance at the sensor. |\n| `surface_pressure` | hPa | 725.95\\* | 1011.33\\* | meters | Air pressure at the surface. |\n| `terrain_height` | km | 0.026\\* | 2.915\\* | meters | Elevation with respect to WGS84 reference ellipsoid. |\n\n\\* estimated min or max value\n\n### Image Properties\n\n**Image Properties**\n\n| Name | Type | Description |\n|---------------------|--------|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------|\n| flight_id | STRING | Research flight number. |\n| basin | STRING | Oil and Gas basin (e.g. Permian) or area of interest (e.g. New York City). |\n| time_coverage_start | STRING | Data collection start time in YYYY-MM-DDThh:mm:ssZ format STRING (ISO 8601). |\n| time_coverage_end | STRING | Data collection end time in YYYY-MM-DDThh:mm:ssZ format STRING (ISO 8601). |\n| processing_id | STRING | (internal) Processing run identifier that represents the calculations that led to the features. It is not an attribute describing the flight, but the processing pipeline. |\n\n### Terms of Use\n\n**Terms of Use**\n\nUse of this data is subject to [MethaneSAT's Content License Terms of\nUse](https://www.methanesat.org/sites/default/files/2025-02/MethaneSAT%20-%20Content%20License%20Terms%20of%20Use%20%28Revised%202-12-2025%29%5B25%5D.pdf).\n\n### Citations\n\nCitations:\n\n- Chan Miller, C., Roche, S., Wilzewski, J. S., Liu, X., Chance, K., Souri,\n A. H., Conway, E., Luo, B., Samra, J., Hawthorne, J., Sun, K., Staebell, C.,\n Chulakadabba, A., Sargent, M., Benmergui, J. S., Franklin, J. E., Daube, B.\n C., Li, Y., Laughner, J. L., Baier, B. C., Gautam, R., Omara, M., and Wofsy,\n S. C. 2023. Methane retrieval from MethaneAIR using the CO2 Proxy Approach:\n A demonstration for the upcoming MethaneSAT mission, EGUsphere \\[preprint\\].\n [doi:10.5194/egusphere-2023-19623](https://doi.org/10.5194/egusphere-2023-1962),\n\n### Explore with Earth Engine\n\n| **Important:** Earth Engine is a platform for petabyte-scale scientific analysis and visualization of geospatial datasets, both for public benefit and for business and government users. Earth Engine is free to use for research, education, and nonprofit use. To get started, please [register for Earth Engine access.](https://console.cloud.google.com/earth-engine)\n\n### Code Editor (JavaScript)\n\n```javascript\nvar dataset = ee.ImageCollection(\"EDF/MethaneSAT/MethaneAIR/L3concentration\");\n\nvar fluxVisParams = {\n bands: ['XCH4'],\n min: 1870,\n max: 2030,\n palette: ['#070088','#a3069b','#cc4e64','#ffa826','#edfb59'],\n};\n\n// Center on one of the available areas of interests.\nMap.setCenter(-102.9, 32, 8);\nMap.addLayer(dataset, fluxVisParams, 'Retrieved column-averaged dry-air CH4 mole fraction');\n```\n[Open in Code Editor](https://code.earthengine.google.com/?scriptPath=Examples:Datasets/EDF/EDF_MethaneSAT_MethaneAIR_L3concentration) \n[MethaneAIR L3 Concentration v1](/earth-engine/datasets/catalog/EDF_MethaneSAT_MethaneAIR_L3concentration) \nThis 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, ... \nEDF/MethaneSAT/MethaneAIR/L3concentration, atmosphere,climate,edf,emissions,ghg,methane,methaneair,methanesat \n2021-08-06T00:00:00Z/2023-10-14T00:00:00Z \n27.62 -118.42 54.6 -73.44 \nGoogle Earth Engine \nhttps://developers.google.com/earth-engine/datasets\n\n- [](https://doi.org/https://methanesat.org)\n- [](https://doi.org/https://developers.google.com/earth-engine/datasets/catalog/EDF_MethaneSAT_MethaneAIR_L3concentration)"]]
