# Predicting Runoff from the Weigan River under Climate Change
## 4 Discussion  
### Evaluation of Models' Simulation Capability  
In this study, data from seven global climate models from different countries and institutions were selected for delta downscaling bias revision for the upper watershed of the Weigan River outflow basin and evaluated and analysed in conjunction with Taylor diagrams. The maximum temperature simulated by the ACCESS-ESM1-5 model is better than the other six models, and the minimum temperature simulated by the ACCESS-ESM1-5, CanESM5 and INM-CM5-0 models is better than the other climate models. To date, most of the studies on climate models focus on the Tibetan Plateau and the Loess Plateau, and there are relatively few studies focused on Northwest China. In their simulation of temperature using various model data, [PERSON] et al. [32], [PERSON] et al. [33] and [PERSON] [34] reported that the ACCESS-ESM1-5 model performs very well in temperature simulation and has the best effect. But the research results reported by [PERSON] et al. [35] and [PERSON] et al. [36] showed that models such as CMCC-ESM2 and CanESM5 are the best for simulation of temperature, and the ACCESS-ESM1-5 model is not as effective. [PERSON] et al. [17] showed that the temperature series simulated by the CanESM5 model is superior to the actual observed series. It can be seen that the optimal temperature model data identified in different regions are not exactly the same. Meanwhile, in this study, as far as the temperature data of each model are concerned, except for the CNRM-ESM2-1 model where the simulation accuracy of the maximum and minimum temperatures is close to that of the observed data, the simulation effect of the minimum temperature of the other models is better than that for the maximum temperature. This is more consistent with the results obtained by [PERSON] et al. [37] in their study on the assessment of extreme climate change in the upper and middle Huaihe River Basin, which concluded that the simulation ability of the ACCESS-ESM1-5 and CMCC-ESM2 models for the minimum temperature is better than that for the maximum temperature. As for the simulation of precipitation data, the MRI-ESM2-0 model has better simulation results, and the simulation results of the remaining six models, such as ACCESS-ESM1-5, are closer to each other, with a moderate correlation with the actual observation series. [PERSON] et al. [38], [PERSON] et al. [39] and [PERSON] et al. [40] also agreed that the MRI-ESM2-0 model can simulate the actual observed precipitation better when predicting the evolution of future hydrometeorological elements. The results of this study are more consistent with their results. On the other hand, [PERSON] et al. [41], [PERSON] [42] and [PERSON] [43] reported that the precipitation data simulated by the MRI-ESM2-0 climate model differed greatly from the actual observed series. [PERSON] et al. [44] concluded that the ACCESS-ESM1-5 model is the single model with the best simulation effect in predicting daily-scale precipitation at the Jinsha River basin. It can be seen that the data of the optimal precipitation models in different regions are also not completely consistent. From the point of view of the meteorological elements simulated by each model, the simulation effect of air temperature is better than that of precipitation, which is more