Detection, quantification and monitoring of methane emissions from space

Luis Guanter

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Environmental Defense Fund Europe

Research Institute of Water and Environmental Engineering, Universitat Politècnica de València (Spain)

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@UNEP/IMEO

A diverse ecosystem of methane-sensitive missions

A rich ecosystem of methane-sensitive satellites has emerged in the last years

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Satellites to guide methane mitigation efforts by:

• Detection, quantification and monitoring of active point sources (above a given detection limit)
• Quantification of emissions at regional-level

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This presentation: Overview of the use satellites to detect methane emissions from human activities (esp. the O&G sector)

Jacob et al., ACP, 2022

The detection of methane sources from space is on the focus

A diverse ecosystem of methane-sensitive missions

Area flux mappers (TROPOMI)

7 km/pixel, global daily coverage,

>10 t/h emissions, in general no attribution

Point source imagers

~30 m/pixel, sparse acquisitions

>0.1-1 t/h emissions, attribution to sources

• Heterogeneous ecosystem of methane-sensitive missions (spectroscopic measurements in 1000-2500 nm)
• Depending on spatial sampling: area flux mappers and point source imagers (Jacob et al., 2022)

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As of 2026, include:

GHGSat (Canada), Tanager (USA), PRISMA (Italy), EnMAP (Germany), EMIT (USA), GF5-02 AHSI (China), Sentinel-2 (EU), Landsat (USA)

Copernicus Sentinel-5P/TROPOMI (area flux mapper)

Application #1

Detection of individual ultra-emission events and hotspot regions (daily global surveillance, very large plumes)

Application #2

Estimation of regional fluxes through the inversion of atmospheric transport models

• TROPOMI - operational, global and daily sampling, but coarse resolution

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2974 super-emission detections during 2021

Schuit et al., ACP, 2021

Varon et al., Integrated Methane Inversion (IMI 1.0)

https://doi.org/10.5194/gmd-15-5787-2022

Worldwide inference of national methane emissions by inversion of satellite observations with UNFCCC prior estimates

Inferring country-level emissions from TROPOMI

East et al., Nat. Comm. 2026

Methane mapping with point source imagers

Malfunctioning flare,

Permian Basin, NM, USA 9 Feb 2022

Instruments covering methane absorptions in 1600-2450 nm

Allow attribution to sources and lower detection limits (>100 kg/h)

Two classes of missions

• Hyperspectral missions (GHGSat, EnMAP, PRISMA, ...): 30-m resolution, medium sensitivity (high for GHGSat!), sporadic acquisitions, spatial coverage 30-60 km, require tasking
• Multispectral missions (S-2/Landsat): 20-30 m resolution, low sensitivity, but “monitoring” with frequent and global coverage

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Roger et al.,

IEEE TGRS (2024)

Methane plume detections with the EnMAP satellite mission

• High resolution methane mapping with the EnMAP imaging spectroscopy mission (DLR)

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• Hundreds of sites around the world sampled for the detection of methane emissions

�Kazakhstan 2023 well blowout��

• Massive emission event in Kazakhstan active between 9 June and 25 Dec 2023
• Largest leak ever documented: ~131 kt methane

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Guanter et al., ES&TL, 2025

Methane emissions from landfills

Dogniaux et al., Nature, 2025

• Landfills are important methane sources

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• Large efforts to survey methane emissions from landfills worldwide using satellite data

Survey of methane point emissions in Turkmenistan combining TROPOMI and point source imagers

• Definition of methane “hotspots” (local/regional enhancements) based on the analysis of TROPOMI data and others
• Investigation of individual point sources with point source imagers (PRISMA, ZY1, Landsat-8, and Sentinel-2)
• A total of 29 point sources were identified

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Irakulis-Loitxate et al., ES&T (2022)

Looking into long time series of emissions with Landsat

Irakulis-Loitxate et al., ES&T, 2022

UN Environment Programme: �IMEO & MARS

The focus of UNEP’s International Methane Emissions Observatory (IMEO) is to catalyze reductions of methane emissions using transparent, data-driven approaches.

IMEO consists of several efforts, including the Methane Alert and Response System (MARS):

• Satellite data to drive detection, notification and mitigation processes of active methane sources
• Launched at COP28 (November 2023)
• Based on TROPOMI and a number of plume imagers
• Fast growing number of source detection and emission notification over the last months

→ Service provided by IMEO for free to stakeholders: the designated government focal points and OGMP companies

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@UNEP/IMEO

• EDF satellite mission to produce quantitative data on methane emissions, with a focus on the oil and gas sector

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• Launched on March 2024, stopped operations in June 2025

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• Ιntended to cover the gap between point source imagers and global flux mappers (point sources + total emissions)

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• Acquired data from ~200x200 km² targets around the planet

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• Data products:
• Level 1: top-of-atmoshere radiance
• Level 2/3: XCH4 maps (native spatial sampling or gridded)
• Level 4: total emissions (area+point sources)

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• Data available from the public data portal, the Google Cloud, and the Google Earth Engine

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The MethaneSAT mission

MethaneSAT L4-point source product

• L2/L3 products (XCH4 maps, with and without spatial gridding) being generated for each acquisition
• L4 Point Source products: generated for each acquisition on a best-effort basis

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MethaneSAT L4-point source product

• L2/L3 products (XCH4 maps, with and without spatial gridding) being generated for each acquisition
• L4 Point Source products: generated for each acquisition on a best-effort basis

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MethaneSAT �area-sources �product��Emissions �in a 4x4 km² grid���MethaneSAT is the only system able to provide �high-resolution �emission maps �������Screenshot from MethaneSAT’s data portal�https://portal.methanesat.org�

27-Dec-2024

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MethaneSAT L4 Data Availability

https://developers.google.com/earth-engine/datasets/publisher/edf-methanesat-ee

https://portal.methanesat.org

MethaneSAT Portal

Google Earth Engine

+ Buckets in the Google Cloud for L1/L2/L3 products

https://egusphere.copernicus.org/preprints/2025/egusphere-2025-6126/

Methane intensity and emissions across major oil and gas basins (...) using MethaneSAT observations

(Williams et al, under review)

• Mean emission maps for several basin generated from MethaneSAT L4 data, including Amy Darya-UZB

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• Emissions evaluated in terms of methane intensity and comparison to other estimates�

Methane intensity and emissions across major oil and gas basins (...) using MethaneSAT observations (Williams et al, under review)

https://egusphere.copernicus.org/preprints/2025/egusphere-2025-6126/

• Amu Darya emissions dominated by O&G and agriculture

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• Low methane intensity when normalized per gas production (leaks)

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• High methane intensity when normalized per energy (oil+gas) production�

Methane intensity and emissions across major oil and gas basins (...) using MethaneSAT observations (Williams et al, under review)

https://egusphere.copernicus.org/preprints/2025/egusphere-2025-6126/

• For UZB, relatively good agreement with inventories
• Main discrepancy in the ratio between O&G and non-O&G

• A rich ecosystem of methane-sensitive satellites has emerged in the last years
• Applications:
• Detection of methane super-emitters
• Estimation of regional emissions
• Satellites are the basis of IMEO-MARS'super-emitter detection and notification programme (next presentation)
• EDF’s MethaneSAT able to provide spatially-resolved information on emissions
• First study featuring Uzbekistan’s Amu Darya emissions available on line

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Summary

Thank you for your attention!

@UNEP/IMEO

Medium spatial resolution & high temporal resolution:�SLSTR, VIIRS, Geostationary

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• Multiband+Multipass methane retrievals developed for S-2 and Landsat have been recently applied to “medium resolution” multispectral imagers

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• Poorer spatial resolution (~500 m) than S-2, but daily or sub-daily temporal coverage of very large plumes

Watine-Guiu et al., PNAS (2023)

Pandey et al., RSE (2023)

MethaneSAT Targets

• Over 400 target areas (200 km × 200 km) defined
• Focus on oil & gas basin and agricultural regions, but other target categories included
• Spectrometers “scan” the targets for 30 sec to generate spectral data cube

A diverse ecosystem of methane-sensitive missions

Area flux mappers (global):

• TROPOMI: 7 km/pixel, global daily coverage, >10 t/h emissions, difficult attribution to sources
• A number of other missions coming up , in particular MethaneSAT (~400 m pixel, 200 km coverage)
• GOSAT-GW, S-5 & CO2M also coming up

Point source imagers (local):

• Spatial sampling ~30 m
• Allow attribution to sources and lower detection limits (300-10,000 kg/h)

Two classes of satellite missions

• Spectrometers (GHGSAt, PRISMA, EnMAP, EMIT): medium-high sensitivity, sparse acquisitions, require tasking
• Multispectral imagers (S-2/Landsat): low sensitivity, but “monitoring” with frequent and global coverage

Jacob et al., ACP, 2022

Survey of methane point emissions in the Permian Basin

• ~30 hyperspectral satellite images (GF5, ZY1, PRISMA) processed
• 37 plumes with Q>500 kg/h found
• 19 of them from one single overpass of GF5 AHSI

Irakulis-Loitxate, Guanter et al., Science Advances, (2021)

Retrieval of gas concentration from space

• Solar radiation interacts with gases in the atmosphere, and a “radiance spectrum” is measured by the satellite instrument
• Inverse problem: what is the amount of gas causing the observed spectrum? Physical models reproduce the absorption of solar radiation by gases in the atmosphere and generate XCH4 maps
• Plume identification based on a supervised approach. Main criteria: consistency with winds and no correlation with surface structures
• Flux rates (Q, in kg-CH4/hr) estimated for the individual plumes, sensitivity ~[100-10,000] kg/h, depending on instrument, surface type and wind speed

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