## 4 Warm Core Structure Retrieval Experiment
### Retrieval Results  
This study utilizes Typhoon Yagi on 5 September 2024, and Hurricane Beryl on 1 July 2024 to retrieve warm core structure. As shown in Figure 10, (a-c) represent the brightness temperature observations of Typhoon Yagi by FY-3F MWHS channel 1 (89 GHz), NOAA-20 ATMS channel 16 (88.2 GHz), and FY-3E MWHS channel 1 (89 GHz) on 5 September 2024, respectively, with the black solid line representing the cross-section of the warm core. (d-f) are the warm core structures retrieved from FY-3F, NOAA-20, and FY-3E, respectively, and the corresponding times for them are 02:31 UTC, 04:54 UTC, and 09:49 UTC, respectively. (g-i) represent the temperature distribution of Typhoon Yagi at approximately 250 hPa, retrieved from FY-3F, NOAA-20, and FY-3E, respectively. The retrieval algorithm for the warm core structure typically involves calculating the temperature anomaly, which is the result of subtracting the average temperature profile of the region outside a TC from the temperature profile of the TC cross-section. In this experiment, the calculation range for the average temperature profile is from 550 km to 650 km away from the center of the TC. Figure 10: Brightness temperature observations from FY-3F MWHS channel 1 (**a**), NOAA-20 ATMS channel 16 (**b**), and FY-3E MWHS channel 1 (**c**) for Typhoon Yagi on 5 September 2024 (units: K). Warm core structures of Typhoon Yagi retrieved from FY-3F at 02:31 UTC (**d**), NOAA-20 at 04:54 UTC (**e**), and FY-3E at 09:49 UTC (**f**) on 5 September 2024 (units: K). Temperature distributions of Typhoon Yagi at approximately 250 hPa retrieved from FY-3F (**g**), NOAA-20 (**h**), and FY-3E (**i**) (units: K). Figure 10d-f show that the maximum temperature anomalies are generally distributed at an altitude of around 250 hPa. The maximum temperature anomaly is all above 8 K. For the closely timed FY-3F and NOAA-20 (Figure 10g,h), although the TC is located at the edge of the ATMS orbit, it is evident that their temperature distributions around 250 hPa are also relatively consistent. The results indicate that for TC observed within close time intervals, the retrievals from different satellites demonstrate good consistency. In order to validate the retrieval results, the retrieval temperature profiles within a 200 km radius of the TC center were extracted and spatially and temporally matched with the ERA5 temperature profiles for error analysis using two statistical metrics: root mean square error (RMSE) and mean error (ME, defined as the retrieval minus ERA5). The ERA5 temperature profile data vertically covers a range from 1000 hPa to 1 hPa, encompassing 37 pressure levels. To facilitate comparison, the ERA5 data were interpolated to equivalent pressure levels as retrieval results. Figure 11 displays the distribution of ME and RMSE between retrieval results from three satellites and ERA5 within a vertical range from 1000 hPa to 100 hPa. The ME for FY-3F, NOAA-20, and FY-3E are 0.377 K, \(-\)0.235 K, and 0.518 K, respectively, while the RMSE for the same satellites are 1.395 K, 1.007 K, and 1.418 K, respectively. To further demonstrate the reliability of the results, the retrieval results of NOAA-20 ATMS were compared with MiRS products. As shown in Figure 12, it can be observed that the retrieval results have an ME that is approximately 0.3 K less and a RMSE that is roughly 0.8 K smaller compared to MiRS products. In addition, the warm core structures of Hurricane Beryl on 1 July and 2 July 2024, were also retrieved. As shown in Figure 13, (a) to (c) represent brightness temperature  
Figure 11: The distribution of ME (dash) and RMSE (solid) for FY-3F (**a**), NOAA-20 (**b**), and FY-3E (**c**) (units: K). Figure 12: (**a**) The distribution of ME (**a**) and RMSE (**b**) for GSDART (black) and MiRS (red) compared to ERA5 (units: K). observations near 89 GHz from the instruments, while (d) to (e) depict the retrieved warm core structures. The results indicate that the maximum temperature anomalies are all distributed between 300 hPa and 200 hPa.