## 1 Introduction  
With the increasing severity of the greenhouse effect, the focus on greenhouse gas emissions has gradually intensified. Methane, a potent greenhouse gas with a global warming potential approximately 84 times greater than carbon dioxide over 20 years [1], has attracted particular attention. In response, countries and organizations worldwide are actively taking steps to advance methane emissions reductions. Methane emissionscould be classified into anthropogenic and natural categories. Importantly, approximately 60% of methane comes from anthropogenic emissions [2], with the oil and gas sector as the largest contributor, while coal mining also demands attention [1]. A substantial portion of anthropogenic emissions originates from point sources, defined as small facilities emitting high methane concentrations [3]. Equipment leaks and pipeline ruptures are the predominant causes of these emissions, making them unpredictable and intermittent. Furthermore, point source emissions follow a heavy-tailed distribution [3; 4], indicating that point sources with small emissions account for the majority. Existing XCH\({}_{4}\) observation technologies broadly include ground-based, airborne, and satellite-based methods [5]. Satellite-based systems stand out for providing large-scale, high-precision measurements of methane concentrations, enabling near-real-time emissions monitoring. In addition, satellites designed for methane monitoring can be divided into two principal types: area flux mappers and point source imagers [6]. These two types of satellites work in tandem, with area flux mappers identifying regions with high methane emissions, while point source imagers subsequently pinpoint and assess specific methane sources. Two notable area flux mappers currently in use are the Greenhouse Gases Observing Satellite (GOSAT) and the Tropospheric Monitoring Instrument (TROPOMI), both operating in the short-wave infrared (SWIR) spectrum [7; 8; 9; 10]. These satellites are optimized for high spectral resolutions (0.06 nm of GOSAT, 0.25 nm of TROPOMI), at the expense of spatial resolutions. Consequently, they struggle to locate point source emissions directly. The advent of point source imagers fills this gap with their high spatial resolution. According to differences in spectral resolution, such satellites can be further categorized into hyperspectral and multispectral imaging spectrometers. In this context, we focus on hyperspectral systems, which offer high precision in detecting methane plumes. The Hyperspectral Precursor of the Application Mission (PRISMA), launched by the Italian Space Agency in 2019, has demonstrated potential in mapping methane point sources typically associated with fossil fuel production [11]. Similarly, the German satellite of Environmental Mapping and Analysis Program (EnMAP) and NASA's Earth Surface Mineral Dust Source Investigation (EMIT), which both entered space in 2022, offer comparable capabilities for detecting methane emissions [12; 13]. Additionally, Chinese satellites, such as the GaoFen5B-advanced hyperspectral imager (GF5B-AHSI) and the ZiYuan1-advanced hyperspectral imager (ZY1-AHSI), also exhibit similar detection potential [14]. Greenhouse gas satellites (GHGSats) are the first commercial satellite constellation dedicated to methane plume monitoring [15]. MethaneSAT, launched by the Environmental Defense Fund (EDF) in 2024, concentrates on the oil and gas industry and can detect methane concentration changes as small as 3 ppb [16]. Collectively, these imaging spectrometers with different parameters have achieved global multi-site detection of methane plumes [17; 18; 19]. For instance, the GHGSat constellation has demonstrated the capability to detect small methane emission plumes down to 180 kg/h over homogeneous surfaces [20]. Similarly, PRISMA has been shown to reliably detect plumes of approximately 500 kg/h [11], while EnMAP offers a comparable detection capability [21].