This study validates a methane remote sensing detection scheme based on a Fabry-Pérot (F-P) interferometer, aimed at meeting the requirements for spaceborne methane point-source detection. As an important greenhouse gas, methane plays a key role in global climate change, and accurate monitoring of its localized emissions is of great significance for environmental governance and climate change mitigation. This work systematically evaluates the feasibility of the proposed scheme, providing theoretical and technical support for the development and application of spaceborne methane detection systems.
A combined approach of theoretical modeling, numerical simulation, and experimental validation is employed. First, a physical model integrating methane absorption characteristics and F-P interferometric modulation mechanisms is established to describe the coupling relationship between methane spectral absorption and interferometric transmission, enabling simulation of system spectral responses under varying methane concentration conditions. Based on this model, key parameters such as cavity length and reflectivity are analyzed through numerical simulations to optimize the system's modulation performance for methane absorption features.
The experimental validation consists of three parts: interferometer performance characterization, methane concentration variation experiments, and outdoor imaging experiments. The optical performance of the F-P interferometer is first evaluated, focusing on fringe contrast and spectral resolution to verify that the core component meets system design requirements. Methane concentration variation experiments are then conducted by adjusting methane concentration in gas bags to obtain system responses and evaluate its sensitivity to concentration changes. Finally, outdoor imaging experiments are carried out under real environmental conditions to verify system performance in practical scenarios.
The results show that the proposed model effectively captures the interaction mechanism between methane absorption and F-P interferometric modulation. System performance is significantly influenced by interferometer parameters and modulation characteristics. A trade-off between spectral resolution and signal intensity must be considered in the design, while ensuring accurate alignment between transmission peaks and methane absorption features. Simulation results indicate that parameter optimization enables effective modulation while maintaining signal strength, and accurately reflects the system response to methane concentration variations.
Experimental results show that the F-P interferometer exhibits excellent stability and optical performance, with high fringe contrast and good spectral resolution, providing a stable and reliable modulation signal for the detection system. The methane concentration variation experiments demonstrate good system sensitivity: when the methane concentration changes by 380 ppb, the maximum relative change in the system output signal reaches 7.4%. Further comparison between outdoor imaging results and laboratory measurements shows strong consistency in the retrieved spectral features. The characteristic absorption features of methane are clearly identifiable, while additional absorption structures are primarily attributed to overlapping absorption from carbon dioxide and water vapor in the atmosphere. These results indicate that the system can effectively distinguish target gas signatures from background atmospheric components, providing reliable support for subsequent retrieval and quantitative analysis.
For point-source monitoring applications, methane concentration enhancements in typical oil and gas leakage scenarios can reach several hundred ppb or higher, exhibiting strong high-contrast spatial distributions. The proposed method shows good sensitivity to such concentration perturbations and is capable of effectively detecting abnormal enhancement signals. In terms of spatial performance, with appropriate matching between the telescope system and imaging parameters, a spatial resolution of approximately 25-50 m can be achieved under typical orbital conditions, enabling fine localization of methane point-source emissions. In terms of spectral performance, the system can effectively resolve methane absorption features, providing reliable support for subsequent retrievals.
In summary, the proposed detection scheme demonstrates strong feasibility for spaceborne point-source methane monitoring and can meet relevant technical requirements. The system exhibits balanced performance in concentration sensitivity, spatial resolution, and spectral discrimination capability, providing a viable technical solution for the engineering implementation of spaceborne methane detection systems, and laying a solid theoretical and experimental foundation for further optimization and development. Moreover, the integrated methodology of theoretical modeling, simulation analysis, and experimental validation presented in this work may also serve as a useful reference for other spaceborne trace gas remote sensing technologies.