To further improve the accuracy of regional crop yield estimation based on data assimilation, a novel EnSRF assimilation algorithm based on a variable time window and four-dimensional extension (VW-4DEnSRF) was proposed. In this research, taking Hengshui City of Hebei Province as the study area and winter wheat as the research crop, based on the WOFOST crop model and the proposed VW-4DEnSRF algorithm, a crop yield assimilation system was successfully constructed after parameter sensitivity analysis and parameter calibration of the crop model. Supported by the field-measured crop yield data and based on the effective validation of the yield assimilation system at a single point scale and in a typical experimental area, the scale optimization of grid size for regional yield estimation was effectively selected. Finally, combining the WOFOST model and inverted remotely sensed LAI, the regional winter wheat yield simulation under the optimal grid size of 500 m was carried out effectively through comparison with the field-measured yield data and official statistical yield data at the county level. Among them, the R², adjusted R² and RMSE between the simulated yield and ground-measured yield were 0.481, 0.471 and 801.4 kg^.ha⁻¹, respectively. The mean value of the estimated yield of winter wheat in Hengshui City was 6787 kg^.ha⁻¹, and the RMSE and RE between the estimated yield and official yield were 416.7 kg^.ha⁻¹ and 4.56%, respectively. These above results showed that the crop yield assimilation system based on the WOFOST model and proposed VW-4DEnSRF algorithm had good performances at both the single-point level and regional level, which proved that the proposed algorithm was feasible and effective at simulating crop yield over a large area

为了进一步提高基于数据同化的区域作物产量估算的准确性，提出了一种基于可变时间窗和四维扩展的EnSRF同化算法（VW-4DEnSRF）。本研究以河北省衡水市为研究区域，以冬小麦为研究作物，基于WOFOST作物模型和提出的VW-4DEnSRF算法，通过参数敏感性分析和参数化，成功构建了作物产量同化系统。作物模型的校准。在实地测得的作物单产数据的支持下，基于单点规模和典型实验区域单产同化系统的有效验证，有效选择了用于区域单产估算的网格尺寸的尺度优化。最后，结合WOFOST模型和反向遥感LAI，通过与县级实地测得的产量数据和官方统计的产量数据进行比较，有效地进行了最佳网格尺寸为500 m的区域冬小麦产量模拟。其中，模拟产量与地面测得的产量之间的R ²，调整后的R ²和RMSE为0.481、0.471和801.4  kg ^。ha ^-1。衡水市冬小麦估计产量平均值为6787 公斤^。ha ^-1，估计单产和正式单产之间的RMSE和RE为416.7  kg ^。ha ^-1和4.56％。以上结果表明，基于WOFOST模型和提出的VW-4DEnSRF算法的作物单产同化系统在单点水平和区域水平上均具有良好的性能，证明了该算法在模拟作物产量上是可行和有效的。大面积