## 3 Results
### Attributing Changes in ET and GPP  
(1) Attributing changes in ET  
To identify the dominant factors that affect the changes in ET and GPP, ten experimental scenarios including the baseline and the detrended scenarios were conducted. The contributions of the climate variables, land-use and cover change (LUCC), elevated atmospheric carbon dioxide (eCO\({}_{2}\)) and their interactive effects on ET are shown in Table 7. The results show that the contribution rate of precipitation to the growth ET in all the six catchments is the largest, with an average contribution of 104.8%. The contributions of the remaining influence factors are temperature (12.8%), solar dimming (\(-\)12.4%) and carbon dioxide (\(-\)7.2%), and then the interactive effects (2.3%), humidity (2.0%), atmospheric pressure (\(-\)1.3%), wind speed (\(-\)0.8%), and LUCC (\(-\)0.2%). In the BGC, the results show that precipitation, temperature, windspeed, atmospheric pressure, humidity and LUCC contributed positive effects, and the effects of sunshine duration, eCO\({}_{2}\) and interactions were negative. However, in the JMC, only precipitation, temperature and interactive effects show positive effects and the other climate variables all contributed negative effects. It should be noticed that the interactive effects could reach up to 21.2% in the JMC, which contributes more than temperature and the other factors. In the BSC, the precipitation could affect the ET increase by up to 164.1%, and sunshine duration contributed to a considerable ET decrease, by 42.5%. In the THC and DSC, all the influence factors have similar contributions. The precipitation, temperature, humidity and windspeed had positive effects on the ET increase, while the sunshine duration, eCO\({}_{2}\), LUCC, atmospheric pressure and interactions led to ET reductions. In the CHC, the precipitation, temperature and windspeed continue to contribute to the ET increase, while the interactions and atmospheric pressure also increase the ET, whereas humidity, sunshine duration, eCO\({}_{2}\) and LUCC contribute negative effects. Figures 11 and 12a display the contributions of the factors on monthly and seasonal ET changes. Generally, precipitation is the dominant factor for ET changes. The positive effects of precipitation occur throughout the year except for the negative effects that occur in January and December in winter. The temperature has a negative effect on ET changes in summer, while it leads to an ET increase in other three seasons, particularly from November to January in winter. The effect of sunshine duration on ET changes is negative in summer and autumn, particularly from September to November, which is the opposite in winter and spring. The eCO\({}_{2}\) contributes to ET increase in autumn and ET decrease in other seasons, especially in winter. The humidity leads to an ET decrease in autumn and ET increase in other seasons, particularly in January and December in winter and it is the dominant factor contributing to ET change in winter. The windspeed has a positive effect on ET increase in most of the months except for June to August in summer. The effects of LUCC and atmospheric pressure on ET are almost rare throughout the year. Additionally, the interactive effects lead to ET reduction, mostly in spring, and its increase in autumn and winter, particularly in September. Overall, precipitation is the dominant factor that increases ET in spring, summer and autumn and decrease ET in winter. In spring, the interactive effects contribute to most of the ET reduction. In autumn, the humidity and sunshine duration are the main factors that reduce ET. However, humidity and temperature are the major reasons for ET increase in winter.