## 2 Materials and Methods
### Calculation of Anomalies  
To avoid the influence of seasonal cycles, Equation (2) was used to calculate the anomalies of SPEI, SM, PPT, LST, GPP, SIF, SIF, SIF\({}_{\text{yield}}\), and NDVI. The anomalies for all parameters were computed pixel-by-pixel from 2007 to 2015 for all datasets.  
\[\text{Y(i,j,t)}^{\prime}\ =\ \text{Y(i,j,t)}\ -\ \overline{\text{Y(i,j)}}, \tag{2}\]  
where Y(i,j,t)\({}^{\prime}\) represents the anomalies of the SPEI, SM, PPT, LST, GPP, SIF, SIF\({}_{\text{yield}}\), and NDVI of pixel (i,j) and time t, denoted as SPEI_anm, SM_anm, PPT_anm, LST_anm, GPP_anm, SIF_anm, SIF\({}_{\text{yield}}\)_anm, and NDVI_anm, respectively; Y(i,j,t) is the original value of the pixel (i,j) at time t; \(\overline{\text{Y(i,j)}}\) is the average value of the pixel (i,j) over the period 2007-2015.  
\begin{table}
\begin{tabular}{c c c c} \hline \hline
**Value** & **SPEI \(\leq\) \(-\)0.5** & **SPEI \(>\) \(-\)0.5** \\ \hline Classification & Drought & No\_drought \\ \hline \hline \end{tabular}
\end{table}
Table 1: Classification of SPEI.  
\begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Type** & **Data Name** & **Spatial** & **Temporal Resolution** & **Time Acquired** & **Source** \\ \hline Downscaled & & & & & [[https://doi.org/10.2905/21935](https://doi.org/10.2905/21935) FFC-B797-4]([https://doi.org/10.2905/21935](https://doi.org/10.2905/21935) FFC-B797-4) \\ SIF & GOME-2 & 0.05\({}^{\circ}\) & 8 Days & 2007–2015 & BEE-94 DA-SFEC85B3F9E1 (accessed on 7 April 2021) \\ \hline GPP & Fluxcom & 0.05\({}^{\circ}\) & Monthly & 2007–2015 & [[http://fluxcom.org/EF-Download/](http://fluxcom.org/EF-Download/)]([http://fluxcom.org/EF-Download/](http://fluxcom.org/EF-Download/)) (accessed on 7 April 2021) \\ \hline LST & MOD11C3 & 0.05\({}^{\circ}\) & Monthly & 2007–2015 & [[http://ladsweb.nascom.nasa.gov](http://ladsweb.nascom.nasa.gov)]([http://ladsweb.nascom.nasa.gov](http://ladsweb.nascom.nasa.gov)) / (accessed on 7 April 2021) \\ \hline PPT & CHIRPS & 0.05\({}^{\circ}\) & Monthly & 2007–2015 & [[https://data.chc.ucsb.edu/products/CHIRPS-2.0/](https://data.chc.ucsb.edu/products/CHIRPS-2.0/)]([https://data.chc.ucsb.edu/products/CHIRPS-2.0/](https://data.chc.ucsb.edu/products/CHIRPS-2.0/)) (accessed on 7 April 2021) \\ \hline SPEI & SPEI-3 & 0.05\({}^{\circ}\) & Monthly & 2007–2015 & [[http://spei.csic.es/](http://spei.csic.es/)]([http://spei.csic.es/](http://spei.csic.es/)) (accessed on 7 April 2021) \\ \hline SM & GLDAS & 0.25\({}^{\circ}\) & Daily & 2007–2015 & [[https://disc.sci.gsfc.nasa.gov](https://disc.sci.gsfc.nasa.gov)]([https://disc.sci.gsfc.nasa.gov](https://disc.sci.gsfc.nasa.gov)) (accessed on 7 April 2021) \\ \hline NDVI & MOD13C2 & 0.05\({}^{\circ}\) & 16 Days & 2007–2015 & [[https://lbdaac.usgs.gov/products/mod13c2v006](https://lbdaac.usgs.gov/products/mod13c2v006)]([https://lbdaac.usgs.gov/products/mod13c2v006](https://lbdaac.usgs.gov/products/mod13c2v006)) (accessed on 7 April 2021) \\ \hline PAR & CERES & 10 km & Daily & 2007–2015 & [[https://data.tpdc.ac.cn/](https://data.tpdc.ac.cn/)]([https://data.tpdc.ac.cn/](https://data.tpdc.ac.cn/)) (accessed on 7 April 2021) \\ \hline fPAR & MOD15A2H & 500 m & 8 Days & 2007–2015 & [[https://ladsweb.modaps.eosdis.nasa.gov/missions-and-measurements/products/MOD15A2H](https://ladsweb.modaps.eosdis.nasa.gov/missions-and-measurements/products/MOD15A2H)]([https://ladsweb.modaps.eosdis.nasa.gov/missions-and-measurements/products/MOD15A2H](https://ladsweb.modaps.eosdis.nasa.gov/missions-and-measurements/products/MOD15A2H)) (accessed on 7 April 2021) \\ \hline \hline \end{tabular}
\end{table}
Table 2: Data source.