## 4 Results
### Identification of Typical Methane Emission Hotspots in China and the United States
The small panels (**a**–**h**) around the main figure display examples of the detected plumes, in accordance with Table 1. The white arrow indicates the direction of the wind. Among the eight plumes detected in the Permian Basin, all exhibited emission rates exceeding 1000 kg/h. Irakulis detected 37 methane plume point sources in Texas within the Permian Basin, with emission rates ranging from 1 t/h to 7 t/h, based on satellite data from GF5-AHSI and PRISMA [25]. To our knowledge, the Delaware sub-basin within the Permian Basin holds the highest number of extreme point emitters observed in a single oil and gas producing region. For instance, the scale of emissions in the Permian is significantly greater than what was previously recorded in the Barnett Shale [42], where only 5 out of 17,400 well pads were found to emit over 300 kg/h. Furthermore, in a comprehensive campaign utilizing the AVIRIS-NG airborne imaging spectrometer, only 7 plumes with emission rates above 1000 kg/h were identified in the Four Corners gas-producing area out of a total of 250 plumes detected [44]. However, it should be noted that the area sampled by the airborne instruments in the Four Corners is smaller than the region covered by satellite imaging spectrometers in the Permian Basin (approximately 60 km \(\times\) 50 km, compared  
Figure 5: Methane plumes and emission rates detected in Permian Basin, with the left panel showing a map of the identified methane plumes. The small panels (**a–h**) around the main figure display examples of the detected plumes, In accordance with Table 1. The white arrow indicates the direction of the wind, red box indicates the study area. Figure 6: Maps of column-averaged dry air mole fraction of methane (XCH\({}_{4}\)) derived from TROPOMI data over the area where the massive methane enhancement was detected (marked with a black cross). The black arrows of different directions and sizes represent wind direction and wind speed. (**a**) Taken on 11 January 2023; (**b**) taken on 12 January 2023.  
to about 150 km \(\times\) 200 km). This suggests that it is the total number of extreme emitters, rather than the spatial density of sources, that makes the Permian Basin such a notable case. By examining the distribution of methane emission rates from coal mine point sources detected in Changzhi, Shanxi, and comparing them with the distribution of methane emissions from oil and gas facilities detected in the Permian Basin, we identified some differences in methane emission characteristics between coal mines and oil and gas facilities. The distribution of methane emissions from coal mines may exhibit a more right-skewed pattern, suggesting a lower frequency of extreme emission events. Methane emissions from coal mines might be more persistent in duration [53; 54; 55], yet the levels of extreme emissions could be lower compared to those from oil and gas facilities. This implies that coal mines are more likely to be detected emitting methane on multiple occasions, which could result in a higher average methane emission level compared to oil and gas facilities. In our satellite dataset, we also observed multiple detections of plumes from the same methane sources. Notably, the Sanyuan Nan Yao Coal Mine in Changzhi, Shanxi, and the EOG Shale Gas Well in Eddy County, New Mexico, were both monitored by the GF5-02 satellite's AHSI payload and EnMAP. However, given the limited revisit frequency of the target detection instruments for these two payloads, we utilized Sentinel-2 satellite data on the Google Earth Engine (GEE) platform for the long-term monitoring of these two sites. This approach allowed us to gain a more comprehensive understanding of the methane emission patterns at these locations, providing a scientific basis for the development of effective emission reduction measures. For a detailed discussion, refer to Section 4.2.