Satellite remote sensing monitoring technology: a new hotspot for global methane monitoring

Methane (CH4) is a significant and potent greenhouse gas. Since the Industrial Revolution, atmospheric CH4 levels have been steadily increasing, with the global average concentration rising from 1.714 × 10⁻⁶ in 1900 to 1.912 × 10⁻⁶ in 2022, making it the most significant global warming factor besides carbon dioxide (CO2). Furthermore, CH4 has a global warming potential 27–30 times higher than CO2. Controlling methane emissions is crucial for controlling global average temperature rise (less than 2 °C and ideally less than 1.5 °C). Therefore, monitoring atmospheric CH4 has become a key focus and hot topic in carbon emission reduction.

Satellite monitoring of methane advantages

Compared to ground-based monitoring stations, satellite observation offers advantages such as wider coverage, higher speed, and more stable cycles. Satellite remote sensing technology can achieve real-time monitoring and tracking of methane emissions globally, providing high-precision, high spatiotemporal resolution data support. This is of great significance for identifying methane emission hotspots, tracing methane sources, and assessing the effectiveness of emission reductions.

Specifically, satellite methane detection relies primarily on analyzing the spectral absorption characteristics of methane at different wavelengths. By processing and analyzing the spectral data received by the satellite, the total amount and distribution of methane in the atmosphere can be estimated. This helps us better understand the sources and transmission processes of methane emissions, providing a scientific basis for developing effective emission reduction policies.

Principle of hyperspectral satellite methane monitoring

Hyperspectral satellites utilize high-resolution, high-sensitivity imaging technology to acquire information about objects by capturing their reflectance spectra. These satellites are capable of resolving within the visible, infrared, and ultraviolet spectral ranges, acquiring spectra at high resolution across different bands to facilitate better analysis and information extraction.

Methods for monitoring methane:

Spectral feature identification: Methane has unique spectral absorption characteristics, which hyperspectral satellites can use to identify and distinguish different methane emission sources.

Data fusion and visualization: Integrate data from different sources to generate a visualized methane emission distribution map, facilitating data analysis and presentation.

Satellite methane monitoring data inversion

To accurately obtain methane emission information, in addition to relying on high-quality data measured by spectrometers, it is also necessary to use advanced inversion algorithms, land-based measurement data, atmospheric information, and other satellite data to estimate and verify the methane concentration in the measurement area. Atmospheric CH4 inversion essentially utilizes the absorption spectra of the corresponding bands observed by satellites to remove interference from other factors and obtain effective information on the CH4 profile or total column. CH4 inversion methods mainly include empirical algorithms, physical algorithms, and neural network algorithms. Due to limitations such as the stability of regression models, empirical algorithms typically have low inversion accuracy, which restricts their practical applications.

Satellite methane monitoring data application

A large amount of future satellite data is expected to be used to guide leak detection and repair efforts. Many oil and gas companies, landfill operators, and some large farms with methane digesters are actively searching for leak sites because methane is valuable in these situations and can be captured and utilized. Therefore, in addition to climate and health impacts, a methane leak is tantamount to releasing profits into the atmosphere. Regular satellite monitoring can quickly notify facility owners and operators so they can diagnose and resolve any problems and verify whether leaks have been repaired.

Simultaneously, satellite data can help warn nearby communities of potential risks, educate the public, and guide law enforcement efforts when companies are unwilling to repair leaks. Measuring trends in high-emission methane events across different periods and basins can also contribute to assessing whether policies are achieving their intended effects.

In general, satellite methane detection relies primarily on analyzing the spectral absorption characteristics of methane at different wavelengths. By processing and analyzing the spectral data received by satellites, the total amount and distribution of methane in the atmosphere can be estimated. This helps us better understand the sources and transmission processes of methane emissions, providing a scientific basis for developing effective emission reduction policies.

In summary, satellite methane capture enables high-precision, high-spatiotemporal-resolution methane monitoring globally, which is of great significance for mitigating global warming and promoting sustainable development.