The Application of FY-3D/E Meteorological Satellite Products in South China Sea Summer Monsoon Monitoring

Based on the vertical atmospheric sounding system carried by the FY-3D meteorological satellite (FY-3D/ VASS) and the new wind radar instrument carried by the FY-3E meteorological satellite (FY-3E/WindRAD), a study of the potential application of research on the changes of temperature, humidity, and ocean wind vector (OWV) during the onset of the South China Sea summer monsoon (SCSSM) was conducted. The applications of these satellite datasets in SCSSM monitoring were evaluated, and the SCSSM onset process in 2022 was analyzed. The results showed that the mean bias of the FY-3D/VASS temperature and specific humidity at 850 hPa, compared with that of the fifth-generation ECMWF reanalysis, were -0.6 K and -0.53 g kg-1, respectively, and the pseu-do-equivalent potential temperature (& theta; se ) was slightly lower, by 1 - 2 K; the distribution of & theta;se was consistent with the seasonal advancement of the SCSSM. Compared with Metop-C/ASCAT, the mean bias of FY-3E/WindRAD zonal wind was positive, and that of meridional wind was negative. The correlation coefficient, mean bias, mean absolute error, and root-mean-square error of the wind speed were 0.79, -0.45, 1.56, and 2.03 m s-1, respectively. The distributions of OWV were consistent, and the region and intensity of strong wind speed were close to each other. The temperature, humidity, and wind reversal during the onset of the SCSSM in 2022 were well monitored by the FY-3D/E-derived & theta;se and OWV dual indices, which are consistent with the SCSSM onset date, the third pentad in May, issued officially by the National Climate Center, China Meteorological Administration. Before the SCSSM's onset in 2022, the tropical storms' pumping effect in early May increased the westerly wind over the tropical ocean north of the equator. After the storm weakened, the southwesterly wind passed across the Indochina Peninsula and reached the South China Sea, causing the SCSSM's onset.