*3.2. Prediction Accuracy with Factor Ablation*

In Section 3.1, the effects of vegetation type and distance between the flux sites on GPP prediction accuracy were then investigated. The training data included temperature (Ta), photosynthetically active radiation (PAR), enhanced vegetation index (EVI), normalized difference vegetation index (NDVI), and land surface water index (LSWI). In this analysis, a feature ablation experiment was conducted to explore the influence of each factor on GPP prediction accuracy.

#### 3.2.1. Test Site GPP without Ta

In this experiment, all Ta data were deleted from the training data, which were then trained for each site flux. The final prediction results are shown in Figure 9. Compared to the prediction results without any feature ablation of the training data, the prediction accuracy of the AR site is significantly improved, while that of the DXST, DXSW, NMC, and ZF sites is greatly reduced. The prediction accuracy of the GL, HBKO, HBSH, and HBSW sites does not change noticeably.

**Figure 9.** Predicted GPP vs. labeled GPP at a single site (no Ta).

#### 3.2.2. Test Site GPP without PAR

In this experiment, all Par data were deleted from the training data, which were then trained for each site flux. The final prediction results are shown in Figure 10. Compared to the prediction results without any feature ablation of the training data, the prediction accuracy trends of the sites are similar to those obtained after removing Ta. The prediction accuracy of the AR site has significantly improved, but not as much as after the removal of Ta. The prediction accuracy of the DXST, DXSW, NMC, and ZF sites is sharply reduced. For the DXST site, the decrease is greater than that after removing Ta, whereas the DXSW, NMC, and ZF sites show some recovery but still perform worse than without any feature ablation. The prediction accuracy of the GL, HBKO, HBSH, and HBSW sites as a whole is lower than that after removing Ta, though it does not change appreciably.

**Figure 10.** Predicted GPP vs. labeled GPP at a single site (no PAR).
