Global Methane Monitoring Satellite Development and Application Cases

Methane monitoring technologies are generally designed based on optical, chemical, and acoustic principles, primarily including hyperspectral infrared imaging spectrometers, thermal imagers, photoionization detectors, and ultrasonic detectors. These devices can be directly installed on production and transportation facilities for online monitoring, or mounted on mobile vehicles such as vehicles, low-altitude aircraft, or drones for sampling and analysis in a specific area. However, traditional monitoring technologies are limited by factors such as manpower, cost, time, and space, making it impossible to obtain continuous and traceable methane emission data over large areas, and lacking the ability to detect large-scale methane leaks. With advancements in satellite remote sensing technology, especially hyperspectral imaging technology, developed countries are accelerating the research and application of this technology in methane monitoring, aiming to build a global methane monitoring system.

△Summary of the performance of the CH4 satellites that have completed or are still in orbit

Development of global methane monitoring satellites

With the deepening of research on global climate change and the maturation of spaceborne greenhouse gas detection technologies, the number of CH4 detection satellites began to increase rapidly from 2017. The launch of multiple CH4 detection satellites based on the shortwave infrared band has promoted the rapid development of global CH4 detection and application research. After the signing of the Paris Agreement, the field of methane satellite monitoring entered a period of rapid development. Official space agencies such as the European Space Agency, the Japan Aerospace Exploration Agency, and the Italian Space Agency launched Sentinel-5P, GOSAT-2, and VEGA satellites, respectively, carrying their respective developed Tropomi, FTS-2, and PRISMA spectrometers to monitor methane emissions globally. In terms of performance indicators, these three agencies have made significant progress in methane emission monitoring thresholds, while the Italian PRISMA spectrometer has also achieved a significant improvement in spatial resolution, with ground monitoring accuracy reaching the 30-meter level.

△Comparison chart of the performance of major global methane monitoring satellites

Progress of my country's methane monitoring satellite

China has also launched a series of satellites to detect atmospheric CH4. The Greenhouse Gases Monitoring Instrument (GMI) onboard the Gaofen-5 (GF-5) satellite uses spatial heterodyne spectroscopy (SHS) to acquire spectral signals in the near-infrared to short-wave infrared band (759–2058 nm), featuring high signal-to-noise ratio and mirrorless operation. GMI's spectral range is similar to SCIAMACHY, and its spectral resolution is the same as TANSO-FTS, enabling it to acquire concentration information of greenhouse gases such as CH4 and CO2, providing data support for source-sink analysis of greenhouse gases. The Hyperspectral Greenhouse Gas Monitor (GAS) onboard the Fengyun-3D satellite uses interferometric spectroscopy to acquire high-resolution spectra in four band windows within the near-infrared to short-wave infrared range, used to obtain concentration information of atmospheric components such as CH4 and CO2, improving the quantitative estimation of surface greenhouse gas fluxes at regional scales.

△GHGSat satellite remote sensing monitors methane emissions from oil and gas facilities.

Commercial methane monitoring satellites continue to make strides.

Commercial satellites primarily target localized oil and gas industrial emission areas, estimating emissions by acquiring high spatial resolution imagery data. The development of commercial satellites has also created excellent conditions for localized CH4 emission monitoring, supplementing global spaceborne CH4 detection capabilities. From 2016 to 2021, GHGSat, a Canadian greenhouse gas satellite company, launched GHGSat-D, GHGSat-C1, and GHGSat-C2 satellites and completed their network, raising the methane emission monitoring threshold and spatial resolution to 100 kg/h and 25 meters, respectively, enabling precise monitoring of methane emission sources such as single ground-based oil and gas production facilities and natural gas pipelines.

Application Cases of Methane Monitoring Satellites

Estimating global and regional CH4 budgets can help improve our understanding of CH4 source-sink distribution and provide a reference for addressing future climate change. Currently, GOSAT data is widely used in estimating surface CH4 fluxes, aiding in the analysis of CH4 source-sink distribution and changes at global and regional scales. It provides reliable evidence for assessing the contributions of different sectors to CH4 emissions and for gaining a deeper understanding of changes in CH4 source-sink distribution and their impact on climate. TROPOMI, with its higher spatiotemporal resolution and significantly larger and more accurate data volume than GOSAT, excels in fine-scale flux estimation. These findings provide scientific data support for global methane budgeting and further understanding of CH4 source-sink changes.

High spatiotemporal resolution satellite-borne CH4 data products can directly reflect anthropogenic CH4 emission processes. TROPOMI has demonstrated its advantage in continuous spatiotemporal detection for CH4 emission monitoring and estimation, and its high-precision detection capabilities also create conditions for the monitoring and quantification of regional area-source CH4 emissions. Combined with synchronously detected atmospheric CO concentration data, the stability of local CH4 emissions can be independently assessed without atmospheric transport models. The GHGSat series of commercial satellites, with high spatial resolution, are designed to acquire CH4 point-source emissions from industrial production. By identifying fine-scale CH4 emission plumes, they have been widely used in local emission monitoring and emission estimation.

Global distribution results of △CH4 column concentration (XCH4)

Application Cases of Methane Monitoring Satellites

Anthropogenic CH4 emissions are a major factor contributing to significant global warming, and accurate regional CH4 detection is of great guiding significance for monitoring and controlling anthropogenic emission processes. The Hefei Institutes of Physical Science, Chinese Academy of Sciences, obtained CH4 absorption spectrum information in the 1.65 μm channel using the Gaofen-5 satellite GMI, and obtained global distribution results of CH4 column concentration (XCH4) that are close to those of similar international instruments.

The Satellite Environmental Application Center of the Ministry of Ecology and Environment conducted global atmospheric CH4 monitoring using the hyperspectral integrated observation satellite in the autumn of 2022 (July 1 to September 30). The monitoring results clearly reflected obvious latitudinal distribution characteristics, and the CH4 inversion accuracy was better than 20 ppm compared with the TCCON station measurement data. The Nord Stream natural gas pipeline leak in September 2022 attracted widespread international attention. To track the development of the incident, the Satellite Environmental Application Center of the Ministry of Ecology and Environment used the satellite on September 30 to conduct emergency monitoring along the Nord Stream natural gas pipeline. In conjunction with Wuhan University, Nanjing University, and other institutions, it conducted remote sensing identification and quantification of CH4 emission anomalies, discovering a relatively obvious CH4 emission anomaly on the Nord Stream 2 pipeline east of Bornholm Island, Denmark, with an estimated emission of approximately 70 t/h.

△ Monitoring of CH4 emissions anomalies along the Nord Stream natural gas pipeline based on hyperspectral integrated observation satellites

After years of construction and development, my country's greenhouse gas observation has shown promise of integrated space-air-ground multi-source data support. This not only provides data and technical support for my country's air pollution prevention and control and air quality forecasting, but also contributes to the construction of a global multi-satellite greenhouse gas observation platform. During the 14th Five-Year Plan period, my country will continue to increase its efforts in the research and development of new satellites and the construction of application systems, further enhancing its remote sensing monitoring capabilities for major global greenhouse gases and air pollutants, and providing remote sensing monitoring data support for achieving the national "dual carbon" strategic goals and addressing global climate change.

Some of the reference materials are from:

Construction of my country's Greenhouse Gas Observation Satellites and Application of Typical Data

Analysis of the Current Status and Development Trends of Atmospheric Methane Observation Satellites Aiming at Carbon Neutrality and Carbon Peak in my country