关键词: FY-3D MWRI, 土壤水分产品, 真实性检验, 河南省, SMAP, 适用性分析

Abstract: [Purposes] This study aims to evaluate the accuracy and applicability of soil moisture products derived from the microwave radiation imager (MWRI)onboard the Chinese Fengyun-3D (FY-3D)satellite over Henan province,providing a scientific basis for the operational application of domestic satellite remote sensing data in regional agricultural drought monitoring and water resource management. [Methods] Using in-situ observations from the Henan automatic soil moisture monitoring network at 0～10 cm depth in 2024 as reference data,the FY-3D ascending and descending soil moisture products are systematically validated after pixel representativeness screening and overpass time matching,and spatial consistency cross-comparison with contemporaneous SMAP products was also conducted. [Findings] The FY-3D soil moisture products exhibited consistent temporal trends with ground observations.The descending product demonstrated significantly better accuracy than the ascending product,with a bias of 0.002 0 m³·m^-3,a root mean square error (RMSE)of 0.027 9 m³·m^-3,and a correlation coefficient of 0.833 6.Pronounced seasonal characteristics were observed： errors were lower in winter and spring (October to April)with RMSE generally below 0.04 m³·m^-3,while errors increased in summer and autumn,peaking in July.Spatially,the correlation coefficient between FY-3D and SMAP products reached 0.720 1,with the highest accuracy observed in the homogeneous agricultural areas of the central Henan Plain (Bias< 0.03 m³·m^-3),while larger errors occurred in the hilly and mountainous regions of western and southern Henan,as well as around water bodies. [Conclusions] The FY-3D soil moisture products demonstrate promising potential for operational applications in the major agricultural areas of Henan Province,particularly during winter and spring and over homogeneous plain farmlands.For summer-autumn periods and regions with complex underlying surfaces,integrated application with multi-source data is recommended．

Key words: FY-3D MWRI, soil moisture products, validity check, Henan province, SMAP, applicability analysis