Yangfan ZHOU,Xingming ZHEN,Yuan SUN,Zui TAO,Zewen DAI,Chi XU,Lin LIU,Yanling DING
The launch of the Gaofen-1 satellite has further enhanced China's Earth observation capabilities. Compared with Sentinel-2, the GF-1 WFV image has a high spatial resolution of 16 m, but lacks the Red-Edge (RE) band and the Short-Wave Infrared (SWIR) band. It is important to analyze the differences in the accuracy of estimating vegetation physiological parameters between the two satellites for further application. In this study, we used linear regression models and a Look-Up Table (LUT) based on the PROSAIL model to assess the performance of GF-1 and Sentinel-2 in estimating LAI of soybean and maize. The results showed that: (1) The EVI simple linear regression of GF-1 outperformed other vegetation indices with a R2 value of 0.81 and the MNLIre model was the best Sentinel-2 model with a R2value of 0.86. (2) GF-1 obtained a comparable accuracy to Sentinel-2 with multiple linear regression models based on spectral bands. The best LAI estimation model of GF-1 produced a Root-Mean-Square Error (RMSE) of 0.54 and a coefficient of determination (R2 ) of 0.90, and the best Sentinel-2 model achieved a RMSE of 0.54 and R2 of 0.89. (3) In terms of LUT based on the PROSAIL model, the optimal band combination for GF-1 were B2 and B4 with a R2 of 0.76 and a RMSE of 0.81, and the optimal band combinations for Sentinel-2 were B3, B6, B7, B8, B8a, and B12 with a R2 of 0.87 and a RMSE of 0.62. This study showed that GF-1 satellite has the ability to accurately monitor crop LAI, which can provide a theoretical basis for the application of GF-1 in agriculture monitoring.