## Materials and Methods
### Data Sources and Our Processing
\begin{table}
\begin{tabular}{c c c} \hline \hline
**Data** & **Spatial Resolution** & **Source** \\ \hline TMP (temperature) & 500 m & Loess plateau science data center, National Earth System Science Data Sharing Infrastructure, National Science and Technology Infrastructure of China” \\  & & [[http://loess.geodata.cn](http://loess.geodata.cn)]([http://loess.geodata.cn](http://loess.geodata.cn)) (accessed on 17 June 2024)”. \\  & & AVHRG GIMMS-3G+ \\ NDVI (Normalized Difference & & \"[[https://daac.ornl.gov/VEGETATION/guides/](https://daac.ornl.gov/VEGETATION/guides/)]([https://daac.ornl.gov/VEGETATION/guides/](https://daac.ornl.gov/VEGETATION/guides/)) \\ Vegetation Index) & 0.0833\({}^{\circ}\) & Global\_Veg_Greenness\_GIMMS\_3G.html (accessed on 11 June 2024)”. \\ LAI (leaf area index) & 0.05\({}^{\circ}\) & GLASS “[[https://glass-product.bnu.edu.cn/](https://glass-product.bnu.edu.cn/)]([https://glass-product.bnu.edu.cn/](https://glass-product.bnu.edu.cn/)) (accessed on 2 March 2024)”. \\ FVC (fractional vegetation cover) & 0.05\({}^{\circ}\) & GLASS “[[https://glass-product.bnu.edu.cn/](https://glass-product.bnu.edu.cn/)]([https://glass-product.bnu.edu.cn/](https://glass-product.bnu.edu.cn/)) (accessed on 2 March 2024)”. \\  & & MOD16A2—MODIS/Terra Net Evaportranspiration \\ ET (evaportranspiration) for validation & 500 m & \"[[https://ladsweb.modaps.eosdis.nasa.gov/missions-](https://ladsweb.modaps.eosdis.nasa.gov/missions-)]([https://ladsweb.modaps.eosdis.nasa.gov/missions-](https://ladsweb.modaps.eosdis.nasa.gov/missions-)) \\  & & and-measurements/products/MOD16A2 (accessed on 10 June 2024)”. \\  & & National Earth System Science Data Center \\ Land use/cover & 1 km & \"[[https://www.geodata.cn/main/](https://www.geodata.cn/main/)]([https://www.geodata.cn/main/](https://www.geodata.cn/main/)) (accessed on 2 June 2024)”. \\ Meteorological data (PRE (precipitation) & & China meteorological forcing dataset \\ rate, TEM (surface temperature, \({}^{\circ}\)C), & 0.1\({}^{\circ}\) & \"[[https://data.tpdc.ac.cn/zh-hans/data/8028b944](https://data.tpdc.ac.cn/zh-hans/data/8028b944)]([https://data.tpdc.ac.cn/zh-hans/data/8028b944](https://data.tpdc.ac.cn/zh-hans/data/8028b944)) \\ water vapor pressure (hPa), and & & -daaaa-4511-8769-965612652c49 /; (accessed on 2 March 2024)”. \\ Albedo & 0.05\({}^{\circ}\) & GLASS “[[https://glass-product.bnu.edu.cn/](https://glass-product.bnu.edu.cn/)]([https://glass-product.bnu.edu.cn/](https://glass-product.bnu.edu.cn/))” (accessed on 2 March 2024)”. \\ VPD (vapor pressure deficit) & 0.5\({}^{\circ}\) & “[[https://crudata.neu.ac.uk/](https://crudata.neu.ac.uk/)]([https://crudata.neu.ac.uk/](https://crudata.neu.ac.uk/)) (accessed on 2 March 2024)”. \\  & & National Earth System Science Data Center \\ Watershed boundary & & “[[https://www.geodata.cn/main/](https://www.geodata.cn/main/)]([https://www.geodata.cn/main/](https://www.geodata.cn/main/)) (accessed on 17 June 2024)”. \\  & & Geospatial Data Cloud “[[https://www.gscloud.cn/](https://www.gscloud.cn/)]([https://www.gscloud.cn/](https://www.gscloud.cn/)) (accessed on 2 March 2024)”. \\  & & \\ \hline \hline \end{tabular}
\end{table} 
Table 1: All data sources used in the study. The accuracy of CMFD data is 0.1\({}^{\circ}\); although the accuracy is low, the dataset contains most of the data required in the PT-JPL model that we use, it has a unified data format and attributes, and it is specifically used for the simulation of land surface processes in China. The driving data will be very helpful for us in simulating the evapotranspiration of land surface processes in China. Another important data LAI could be obtained from the GLASS website of the University of Maryland before the start of research and analysis, but its LAI data as of 2018 have a resolution of 500 m. However, in the subsequent data analysis process, the processing methods that we use, especially multiple linear regression analysis, need to unify the resolution and range size of all data.