Evaluation of the sea surface wind speed product quality derived from the Fengyun-3G MWRI radiometer

Sea surface wind speed (SSWS) is a key parameter in marine meteorology and climate research. The Microwave Radiation Imager Radiometer-Rainfall Mission (MWRI-RM), which was conducted by the Fengyun-3G satellite (FY-3G), is capable of detecting SSWS with great precision globally. To verify the quality of the offshore wind products, this study employed buoy data, ERA5 reanalysis data, and Advanced Microwave Scanning Radiometer 2 (AMSR2) products to conduct a systematic evaluation of the FY-3G MWRI-RM SSWS products from January to June 2024. These findings demonstrate that under clear-sky conditions, the products are highly consistent with the buoy, ERA5, and AMSR2 data. The root mean square error demonstrates stability within 0.88 to 1.70 m/s, and the bias predominantly varies between −0.30 and 0.65 m/s. Furthermore, the coefficient of determination and correlation coefficient exceed 0.85 and 0.90, respectively. However, in the low wind speed section (0‒5 m/s), overestimation occurred because of increased atmospheric water vapor and non-precipitating cloud liquid water, which affect microwave emissivity. In the high wind speed section (> 20 m/s), underestimation was caused by sea surface foam, which alters the emissivity. Accuracy decreased in cloudy/rainy areas, land-sea boundaries, near-sea ice edges, and areas with strong radio frequency interference. There were also systematic differences between the ascending and descending orbits. This study provides a scientific basis for the optimization and application of FY-3G MWRI-RM offshore wind products.