## 3 Results
### Model Accuracy and Fractional Vegetation Coverage  
The accuracy of all three models in simulating FAPAR increased with increasing FVC. FAPAR\({}_{\rm MOD}\) had a MAPE of 19.4%, 131.55%, and 255.6%, and an MPE of 16.8%, 125.2%, and 244.9% for high, medium, and low FVC, respectively. FAPAR\({}_{\rm LAI}\) had a MAPE of 14.0%, 83.4%, and 164.4%, and an MPE of 7.6%, 78.4%, and 158.2% under high, medium, and low FVC, respectively. FAPAR\({}_{\rm FVC}\) had a MAPE of 14.0%, 65.4%, and 97.9%, and an MPE of \(-\)4.1%, 33.1%, and 25.4% under high, medium, and low FVC, respectively (Table 4). \begin{table}
\begin{tabular}{c c c c c c} \hline \hline
**FAPAR** & **FVC Range** & **RMSE** & **Bias** & **MAPE (\%)** & **MPE (\%)** \\ \hline  & 70–90\% & 0.124 & 0.068 & 19.4 & 16.8 \\ FAPAR\({}_{\rm MOD}\) & 30–70\% & 0.247 & 0.162 & 131.5 & 125.2 \\  & 0–30\% & 0.314 & 0.221 & 255.8 & 244.9 \\  & 70–90\% & 0.113 & 0.036 & 14.0 & 7.6 \\ FAPAR\({}_{\rm LAI}\) & 30–70\% & 0.189 & 0.112 & 83.4 & 78.4 \\  & 0–30\% & 0.248 & 0.177 & 164.4 & 158.2 \\  & 70–90\% & 0.115 & \(-\)0.056 & 14.0 & \(-\)4.1 \\ FAPAR\({}_{\rm FVC}\) & 30–70\% & 0.223 & \(-\)0.077 & 65.4 & 33.1 \\  & 0–30\% & 0.221 & \(-\)0.129 & 97.9 & 25.4 \\ \hline \hline \end{tabular}
\end{table} 
Table 4: Difference in FAPAR estimation accuracies with different FVC ranges. FAPAR was the same in Figure 1. FAPAR\({}_{\rm MOD}\), FAPAR\({}_{\rm LAI}\), FAPAR\({}_{\rm FVC}\), FVC, RMSE, Bias, MAPE, and MPE were the same in Figure 2. The accuracy of all three models in simulating FAPAR increased with increasing FVC. \begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Model** & **Vegetation Growth Stage** & **RMSE** & **Bias** & **MAPE (\%)** & **MPE (\%)** \\ \hline FAPAR\({}_{\rm MOD}\) & off-peak growth period & 0.274 & 0.201 & 171.9 & 165.8 \\ FAPAR\({}_{\rm MOD}\) & peak growth period & 0.142 & 0.065 & 34.3 & 29.7 \\ FAPAR\({}_{\rm LAI}\) & off-peak growth period & 0.216 & 0.149 & 110.6 & 106.2 \\ FAPAR\({}_{\rm FOV}\) & peak growth period & 0.117 & 0.032 & 22.2 & 15.3 \\ FAPAR\({}_{\rm FVC}\) & off-peak growth period & 0.173 & \(-\)0.038 & 76.1 & 42.2 \\  & peak growth period & 0.197 & \(-\)0.108 & 22.2 & \(-\)7.0 \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Comparison for estimated FAPAR accuracies between different vegetation growth periods. FAPAR, FAPAR\({}_{\rm MOD}\), FAPAR\({}_{\rm LAI}\), FAPAR\({}_{\rm FVC}\), FVC, RMSE, Bias, MAPE, and MPE were the same in Figure 2. FAPAR\({}_{\rm FOV}\) showed clearly higher improvement in the overestimation of FAPAR compared to FAPAR\({}_{\rm LAI}\) and FAPAR\({}_{\rm MOD}\) during the off-peak growth period than during the peak growth period. Compared to FAPAR\({}_{\text{MOD}}\), FAPAR\({}_{\text{LAI}}\) and FAPAR\({}_{\text{FVC}}\) generally showed a decrease in the improvement of FAPAR accuracy with increasing FVC. The proportion of FAPAR decrease gradually increased with decreasing FVC (Figure 7a). The actual statistics of FAPAR\({}_{\text{FVC}}\) reduction compared to FAPAR\({}_{\text{LAI}}\) in this paper also showed a gradual increase with decreasing FVC (Figure 7b). FAPAR\({}_{\text{LAI}}\) decreased MAPE by 27.6%, 36.6%, and 35.7% under high, medium, and low FVC, but MPE decreased by 54.6%, 37.3%, and 35.4%, respectively. FAPAR\({}_{\text{FVC}}\) reduced MAPE by 27.7%, 50.3%, and 60.3% and MPE by 75.4%, 73.5%, and 89.6% under high, medium, and low FVC conditions, respectively (Table 4). Compared to FAPAR\({}_{\text{LAI}}\), the improvement in accuracy for FAPAR\({}_{\text{FVC}}\) was clearer with decreasing FVC.