## 3 Results and Discussion  
### Effects on Land Variables  
Figure 2 shows the spatial distributions of the 24-year (1982-2005) mean soil moisture (SM, m\({}^{3}\) m\({}^{-3}\)) from model simulations (CTL and NEW), and the difference between them. Both the CTL and NEW runs show the same spatial pattern of global SM, with higher values in humid and semi-humid areas, and lower values in arid and semi-arid areas. When the dynamic root distribution was incorporated, SM in most regions decreased by up to 0.02 m\({}^{3}\) m\({}^{-3}\), whereas SM in high-latitude regions increased, mainly because of changes in soil water stress (\(\beta_{\text{t}}\)), due to variations in the root fraction. Similarly to Figure 2, Figure 3 shows the spatial distributions of 24-year mean sensible heat (SH, W m\({}^{-2}\)). SH for global land was found to be positive, which meant that heat was transferred from the land to the atmosphere on average, with larger values in the tropics and smaller values in the middle and high latitudes (Figure 3a,b), in accordance with surface temperature. In the NEW run, SH decreased in tropical regions by up to 20 W m\({}^{-2}\), and the regions with significant changes matched well with those with significant 2-m air temperature decreases (see Section 3.2). Figure 4 shows the spatial distributions of 24-year (1982-2005) mean evapotranspiration (ET, mm year\({}^{-1}\)) from the CTL and NEW model simulations (denoted as CTL_ET and NEW_ET), MTE data (MTE_ET), and the differences between them. The spatial patterns of simulated ET were very similar (Figure 4a,b) and decreased with increasing latitude, consistently with MTE_ET (Figure 4c). This meant that the largest annual ET was found in tropical regions, followed by mid-latitude and high-latitude regions, except for bare soil. The spatial correlation coefficients between the simulated ET with MTE_ET were 0.88 for CTL and 0.90 for NEW (both significant at the 99% confidence level, \(p<0.01\)), but CTL_ET was underestimated in low-latitude regions. The annual global ET values predicted by the two simulations were 372.1 mm year\({}^{-1}\) and 399.5 mm year\({}^{-1}\) respectively, which were much lower than the 496.5 mm year  
of MTE_ET, albeit with an obvious increase in NEW_ET. When the dynamic root distribution was considered, ET in most tropical regions increased, especially in South America and central Africa (Figure 4b), and the ET simulation improved. The overall effect was that dynamic root growth enhanced total evapotranspiration; this was due to increased transpiration and evaporation from vegetation in these areas for the NEW run (not shown), although soil evaporation was weakened to some extent. Five regions with significant differences in ET are framed with red lines in Figure 4d and denoted as R1, R2, R3, R4, and R5. The mean evaporation rates of MTE products for the five typical regions were 338.4 mm year\({}^{-1}\), 1268.2 mm year\({}^{-1}\), 1064.1 mm year\({}^{-1}\), 388.2 mm year\({}^{-1}\), and 888.7 mm year\({}^{-1}\). R2, which was located in South America, had the highest evapotranspiration rate, followed by R3 in South Africa. The ET rates of the CTL runs for the five regions were 299.9 mm year\({}^{-1}\), 1059.5 mm year\({}^{-1}\), 890.2 mm year\({}^{-1}\), 370.1 mm year\({}^{-1}\), and 994.8 mm year\({}^{-1}\). Compared with the MTE product, CTL_ET values for regions R1, R2, R3, and R4 were all underestimated, except for R5, where there was a slight overestimation. When dynamic root growth was taken into account, the ET underestimations for regions R1, R2, and R3 were improved, with their RMSEs reduced by 15.6 mm year\({}^{-1}\), 96.4 mm year\({}^{-1}\), and 56 mm year\({}^{-1}\) (Table 1), but the ET in R4 was further underestimated, and the overestimation in R5 was not improved. In R5, the new rooting scheme let more water be absorbed by plants, causing water stress in the region to weaken, resulting in higher ET.