*3.2. Simulation Accuracy Assessment of Regional ET0*

The scatter density plots of the actual monthly pan evaporation converted values (*ET*0(*pan*)) and simulated *ET*<sup>0</sup> values based on the multi-model ensemble-Hargreaves formula (*ET*0(*Har*)) for the YRB from 1980 to 2014 (Figure 7) showed that the CMIP6-simulated *ET*0(*Har*) for the YRB correlated well with the evaporation dish converted *ET*0(*pan*) at the monthly scale, with a fitted line regression coefficient of 0.9439 and *R*<sup>2</sup> of 0.8523, passing the 99% confidence level test. Although the Hargreaves formula partially underestimated *ET*0, most of the points were near the 1:1 line, making them good reference values for calculating the monthly *ET*<sup>0</sup> under the conditions of missing meteorological observations in the future. Therefore, future *ET*<sup>0</sup> can be simulated using the Hargreaves formula.

**Figure 7.** Scatter density plot of monthly observed pan evaporation converted values (*ET*0(*pan*)) and multi-model ensemble simulations (*ET*0(*Har*)) in the Yellow River Basin from 1980 to 2014.
