## 3 Results
### Similarities and Differences Between the Different Regions  
The annual-scale analyses revealed that the GPP in the HDMs, YGP, and GXB was strongly influenced by the precipitation index (e.g., RDI) and high-temperature indices (e.g., SU and TR), both of which significantly contributed to vegetation growth, although the GPP was also suppressed by the frost index (e.g., FD). At mid- and high altitudes (HDMs and YGP), the increased ETI and CWD increased the GPP. However, DTR had the opposite effect in these regions; an increased DTR increased the GPP in the YGP but suppressed it in the HDMs. In contrast, the SCB showed a weaker response to ECIs, with only CDW and DTR having a significant negative effect on the GPP, while CWD had a significant positive effect.  
The response of the NDVI to ECIs was more complex than that of the GPP. The NDVI was influenced by the standardized index, CECIs, and ECIs. SPI contributed to the NDVI in all regions except the GXB. For ECIs, an increased DTR was more important for the NDVI in the HDMs and SCB, suppressing the NDVI in the HDMs while promoting it in other regions. Although the RDI was more important in the HDMs, its correlation with the NDVI was not significant. SU contributed to a higher NDVI overall, especially in the YGP, but was significantly negatively correlated with the NDVI in the SCB. FD and the CDI decreased the NDVI in the HDMs and YGP, while the NDVI in the SCB was mainly negatively affected by the CDI, ETI, GSL, SU, and TR. In the GXB, the response of the NDVI to ECIs was relatively low, with only the ETI, DTR, GSL, and SU having positive effects.  
The results of the growing season analysis showed that the GPP in the SCB was minimally affected by ECIs, with the ETI emerging as the primary contributing factor, followed by CWD. In the HDMs and YGP, DTR had a significant negative effect on the GPP, although the significance and correlation were relatively low. No other indices showed significant correlations with the GPP in the HDMs and GXB. In the YGP, the GPP was significantly positively correlated with the SPI and CDC, but significantly negatively correlated with the CDI.  
Similarly to the annual-scale results, the response of the NDVI to ECIs during the growing season was complex. The weighting results for the mid- and high-altitude regions (HDMs and YGP) were comparable, except for DTR and CWD. The DTR of the HDMs (\(-\), \(p<0.001\), \(0.3\)) differed significantly from the (\(+\), \(p<0.001\), \(0.109\)) weight of the YGP, and the correlation coefficients were in the opposite directions. While the weights of CWD in the HDMs and YGP did not differ much, they were significantly negatively correlated with the  
Figure 7: Temporal stability of ECIs in relation to EIs across different regions of SWC (growing season). (**a**–**d**) display the temporal stability of GPP with respect to ECIs for the HDM, SCB, YGP, and GXB regions, respectively, over a 38-year period, using 15-year intervals as a moving window. (**e**–**h**) present similar analyses, but with NDVI as the EI.  
NDVI in the HDMs, but not significantly correlated with the NDVI in the YGP. At mid- and high elevations, the ETI was the primary factor contributing to an increase in the NDVI, whereas DTR continued to decrease the NDVI in the HDMs during the growing season but increased it in the YGP. In the HDMs, the NDVI was negatively affected by CWD and CDI, while in the YGP, CDI was only factor with a negative effect.