## 3 Results
### Response of ET and Its Components Variation to Climate Change  
The employed five climate factors explained 86.57%, 85.63%, 39.80%, and 62.54% variance of ET, Ec, Es, and Ei, respectively. Based on the relationship between climate factors and ET, Ec, Es, and Ei, it can be found that the influence of climate factors on ET, Ec, Es, and Ei varied from site-to-site (Table 3). As far as ET, Ec, and Es were concerned, the relative importance of meteorological factors was in order: Ta \(>\) VPD \(>\) SSD \(>\) PT \(>\) WS. While for Ei, the relative importance of meteorological factors was in order: Ta \(>\) VPD \(>\) PT \(>\) SSD \(>\) WS. Overall, the variation of ET, Ec, Es, and Ei in TGRA was dominated by Ta, as can been seen from Table 2, Ta showed the highest relative importance at each station. The % incMSE of Ta were much higher than the corresponding values of VPD, SSD, PT, and WS, generally indicating that the influence of temperature on the variation of ET and its components was more pronounced than other meteorological factors. The % incMSE of Ta was 0.8096 and 0.4818 for ET and EC, respectively, which was much higher than 0.0557 and 0.0555 for Es and Ei, respectively, suggesting that influence of temperature on the variation of ET and Ec was more significant than that on Es and Ei. Similar results were also observed for VPD.  
\begin{table}
\begin{tabular}{c c c c c c c} \hline  & **Station** & **Var Explained (\%)** & **PT** & **Ta** & **WS** & **VPD** & **SSD** \\ \hline \multirow{8}{*}{ET} & BD & 89.84 & 0.0922 & 0.6573 & 0.0204 & 0.3740 & 0.1206 \\  & CS & 86.21 & 0.1097 & 1.0272 & 0.0138 & 0.4316 & 0.1264 \\  & FD & 88.23 & 0.0930 & 0.7969 & 0.0557 & 0.4015 & 0.1345 \\  & FJ & 89.60 & 0.0967 & 0.7408 & 0.0173 & 0.3404 & 0.1123 \\  & JJ & 86.04 & 0.1121 & 0.7987 & 0.0171 & 0.3271 & 0.1782 \\  & SPB & 73.73 & 0.1085 & 0.8812 & 0.0299 & 0.4329 & 0.1254 \\  & WZ & 89.08 & 0.0862 & 0.8290 & 0.0402 & 0.5208 & 0.1885 \\  & XS & 89.79 & 0.1004 & 0.7454 & 0.0120 & 0.3614 & 0.0831 \\  & Mean & 86.57 & 0.0999 & 0.8096 & 0.0258 & 0.3987 & 0.1336 \\ \hline \multirow{8}{*}{Ec} & BD & 90.02 & 0.0288 & 0.3951 & 0.0129 & 0.1837 & 0.0780 \\  & CS & 84.73 & 0.0271 & 0.5732 & 0.0141 & 0.2514 & 0.0851 \\  & FD & 87.76 & 0.0273 & 0.4418 & 0.0326 & 0.2150 & 0.0940 \\  & FJ & 91.16 & 0.0393 & 0.5359 & 0.0161 & 0.1919 & 0.0839 \\  & JJ & 83.54 & 0.0374 & 0.4638 & 0.0089 & 0.1410 & 0.0851 \\  & SPB & 70.36 & 0.0550 & 0.5373 & 0.0257 & 0.2202 & 0.0723 \\  & WZ & 87.54 & 0.0229 & 0.3838 & 0.0148 & 0.1544 & 0.0876 \\  & XS & 89.89 & 0.0381 & 0.5237 & 0.0091 & 0.2211 & 0.0678 \\  & Mean & 85.63 & 0.0345 & 0.4818 & 0.0168 & 0.1973 & 0.0817 \\ \hline \multirow{8}{*}{Es} & BD & 35.42 & 0.0083 & 0.0315 & 0.0025 & 0.0255 & 0.0093 \\  & CS & 29.66 & 0.0076 & 0.0453 & 0.0007 & 0.0264 & 0.0195 \\  & FD & 26.86 & 0.0040 & 0.0321 & 0.0040 & 0.0185 & 0.0086 \\  & FJ & 33.67 & 0.0060 & 0.0225 & 0.0019 & 0.0169 & 0.0076 \\  & JJ & 53.60 & 0.0232 & 0.0815 & 0.0071 & 0.0571 & 0.0280 \\  & SPB & 39.51 & 0.0140 & 0.0756 & 0.0062 & 0.0547 & 0.0120 \\  & WZ & 67.26 & 0.0207 & 0.1137 & 0.0133 & 0.0978 & 0.0332 \\  & XS & 32.43 & 0.0113 & 0.0431 & 0.0025 & 0.0231 & 0.0064 \\  & Mean & 39.80 & 0.0119 & 0.0557 & 0.0048 & 0.0400 & 0.0156 \\ \hline \multirow{8}{*}{Ei} & BD & 65.44 & 0.0188 & 0.1020 & 0.0034 & 0.0233 & 0.0069 \\  & CS & 62.63 & 0.0220 & 0.1270 & 0.0051 & 0.0314 & 0.0120 \\  & FD & 65.74 & 0.0163 & 0.0957 & 0.0048 & 0.0227 & 0.0097 \\  & FJ & 70.16 & 0.0085 & 0.0331 & 0.0003 & 0.0075 & 0.0046 \\  & JJ & 60.74 & 0.0027 & 0.0116 & 0.0004 & 0.0040 & 0.0022 \\  & SPB & 43.67 & 0.0021 & 0.0156 & 0.0002 & 0.0055 & 0.0038 \\  & WZ & 58.74 & 0.0027 & 0.0118 & 0.0004 & 0.0046 & 0.0026 \\  & XS & 73.21 & 0.0178 & 0.0473 & 0.0008 & 0.0109 & 0.0028 \\  & Mean & 62.54 & 0.0114 & 0.0555 & 0.0019 & 0.0138 & 0.0056 \\ \hline \end{tabular}
\end{table}
Table 3: Random forest results (the value of % incMSE) at different sites during 2000–2020.