## 3 Results
### Attributing Changes in ET and GPP
\begin{table}
\begin{tabular}{c c c c c c c c c} \hline \hline
**Catchment** & **Atmospheric Pressure** & **Temperature** & **Humidity** & **Precipitation** & **Windspeed** & **Sunshine Duration** & **CO\({}_{2}\)** & **LUCC** & **Interact** \\ \hline BGC & 3.5\% & 10.5\% & 0.4\% & 90.7\% & 7.9\% & \(-\)0.8\% & \(-\)5.2\% & 0.2\% & \(-\)7.2\% \\ JMC & \(-\)4.3\% & 19.4\% & \(-\)7.4\% & 106.0\% & \(-\)7.9\% & \(-\)16.0\% & \(-\)10.8\% & \(-\)0.3\% & 21.2\% \\ BSC & 0.9\% & \(-\)5.0\% & \(-\)12.8\% & 164.1\% & \(-\)0.9\% & \(-\)42.5\% & \(-\)2.9\% & 0.0\% & \(-\)0.8\% \\ THC & \(-\)0.2\% & 8.5\% & 8.9\% & 104.9\% & 0.5\% & \(-\)10.2\% & \(-\)6.4\% & \(-\)0.1\% & \(-\)5.9\% \\ DSC & \(-\)0.1\% & 11.8\% & 9.2\% & 97.5\% & 4.7\% & \(-\)7.9\% & \(-\)41.1\% & \(-\)11.5\% \\ CHC & 0.2\% & 13.0\% & \(-\)3.0\% & 104.3\% & 4.7\% & \(-\)17.2\% & \(-\)9.7\% & \(-\)0.6\% & 8.4\% \\ Mean & \(-\)1.3\% & 12.8\% & 2.0\% & 104.8\% & \(-\)0.8\% & \(-\)12.4\% & \(-\)7.2\% & \(-\)0.2\% & 2.3\% \\ \hline \hline \end{tabular}
\end{table} 
Table 7: Attributions of annual ET changes in the six catchments. Attributing changes in GPP  
Based on the ten experimental scenarios, the effects of the climate variables, LUCC, eCO\({}_{2}\) and their interactions on GPP are also quantified in Table 8. The results show that eCO\({}_{2}\) contribute the largest GPP increases in most of region within average contribution about 56.7%. The precipitation and temperature also have significant influences on the increase in GPP with the effects of 34.8% and 27.8%, while the sunlight duration, humidity, wind speed, atmospheric pressure, LUCC and the interactive effects have negative effects on GPP growth with the contributions of \(-\)6.8%, \(-\)4.8%, \(-\)3.5%, \(-\)2.4%, \(-\)1.0% and \(-\)0.8%, respectively. We could also find that the effects of the influence factors on GPP changes are various from each catchment in the region. In the BGC and JMC, the precipitation contributes the largest GPP increase, and eCO\({}_{2}\) and temperature also contribute significant increase in GPP. Meanwhile, the interactive effects (39.5%) should also be focused on in the JMC. The effects of atmospheric pressure, windspeed and LUCC are different in the two catchments. In the BSC, the eCO\({}_{2}\) have a large effect increasing the GPP by 108.3%, the humidity and precipitation also have positive effects, while temperature, sunshine duration and the interactions have negative effects. In the THC and DSC, the dominant factor is eCO\({}_{2}\) with the contributions of 66.2% and 73.8%, and the followed factors are temperature and precipitation. The interactive effects could reduce the GPP by 39.7% in the DSC. The effects of the other impact factors are generally small. In the CHC, the most important factors are eCO\({}_{2}\) and temperature increasing the GPP by 66.8% and 45.7%, while precipitation has a negative effect of \(-\)6.6% which is different from the results in other catchments. Meanwhile, the sunshine duration make a large reduction on GPP by 21.3%. The LUCC have a larger negative effect about \(-\)4.9% in the CHC comparing to other catchments. Figures 12b and 13 presents the contributions of the factors on monthly and seasonal GPP changes. The eCO\({}_{2}\) contribute a large GPP increase throughout the year except for small decrease in February. Additionally, the eCO\({}_{2}\) is the dominant factor contributing to GPP increase in summer and autumn, specifically from June to October. Furthermore, precipitation has positive effect on GPP change in all months, and it is the dominant factor leading to an increased GPP in spring. The temperature increases the GPP during a year,  
Figure 11: Attributions of monthly ET changes in the six catchments. particularly from January to March, while it has a slight negative effect in summer. The temperature is the most important factor that contributes to the GPP increase in winter and it also has a great contribution in spring.