## 3 Results
### Satellite Inversion 10 m Wind Field  
#### 3.3.1 HY-2C, CFOSAT Inversion 10 m Wind Field Distribution  
As satellites cannot simultaneously cover the entire global ocean surface, the following assumptions were made in this study: It was assumed that for locations with available satellite data in October 2021, the data would be cumulatively accumulated, and the mean value of all non-empty data points would be interpolated onto a 0.25\({}^{\circ}\)\(\times\) 0.25\({}^{\circ}\) grid. The spatial region encompassed by 30.5\({}^{\circ}\)N to 37.5\({}^{\circ}\)N, and 119\({}^{\circ}\)E to 127\({}^{\circ}\)E, was chosen as the focus of analysis. The Haversine formula [45] was used to calculate the meridional average distance, which was approximately 735.6 km, while the zonal average length was approximately 778 km. In this analysis, the region included 29.4 \(\times\) 31.1 wind cells, each measuring 25 km \(\times\) 25 km, which closely approximated the coverage of satellite observations. Hence, the assumptions mentioned above are considered valid. Based on the assumptions discussed above, in this study we conducted the following analysis: Figure 7 illustrates the average distribution of 10 m wind speeds over the Yellow Sea in October 2021, obtained from HY-2C and CFOSAT retrievals, as well as the WRF model simulation. The left panel of Figure 7 illustrates the 10 m wind field over the Yellow Sea derived from HY-2C and CFOSAT retrievals in October 2021. The image shows that the Yellow Sea wind field retrieved by HY-2C provided coverage for a substantial portion of the region, with a concentration of missing data primarily observed in near-shore areas. The wind speeds in the southern part of the Yellow Sea were greater than those in the northern region, and the maximum wind speeds were observed near the Zhoushan Islands. The middle panel displays the 10 m wind field over the Yellow Sea derived from CFOSAT scatterometer observations in October 2021. The image shows that the scatterometer observations effectively covered a significant portion of the Yellow Sea, with missing data primarily concentrated in near-shore regions. Wind speeds were higher in the southern part of the Yellow Sea than in the northern part, with wind speeds along the coastal areas of the Korean Peninsula being lower than those along the coasts of Shandong and Jiangsu in China. The maximum wind speeds were observed in the vicinity of the Zhoushan Islands. Compared to the wind field derived from the HY-2C retrieval, the missing data range was similar for CFOSAT. HY-2C observations covered the northern part of the sea area extending beyond Jeju Island, and the 10 m wind speeds derived from the HY-2C retrieval were more significant in the northern part of the Yellow Sea compared to the CFOSAT retrieval. The right panel shows the average distribution of 10 m wind speeds over the Yellow Sea and its surrounding areas simulated using the Weather Research and Forecasting (WRF) model. It was evident from the image that wind speeds over the ocean were significantly higher than those over land. The maximum wind speeds over the ocean were observed in the southwestern waters of Jeju Island, while over land, they occurred over large inland lakes. Figure 8 presents the differences between the two satellite retrieval products and the simulated wind speeds from the WRF model under different wind speed conditions. The  
Figure 7: HY-2C, CFOSAT inversion, and WRF simulation of 10 m wind speeds in the mean Yellow Sea surface in October 2021.  
differences were calculated by subtracting the simulated values from the corresponding grid points of the satellite retrievals. For the low wind speeds conditions, the transit data of the HY-2C satellite retrieval on 23 October at 07:19:20 (UTC), 24 October at 21:29:38 (UTC), and October 25 at 21:47:04 (UTC), as well as the CFOSAT satellite retrieval on 23 October at 09:49:15 (UTC), 24 October at 22:14:48 (UTC), and 25 October at 22:00:09 (UTC), were chosen. In this study, wind speeds below 6 m/s were considered low wind speeds.