Hotspots of the sensitivity of the land surface hydrological cycle to climate change

Due to the shortage of the global observational data of the terrestrial hydrological variables, the understanding of how surface hydrological processes respond to climate change is still limited. In this study, the Community Land Model (CLM4.0) with high resolution atmospheric forcing data is selected to simulate the global surface hydrological quantities during the period 1948–2006 and to investigate the spatial features of these quantities in response to climate change at the regional scales. The sensitivities of evaporation and runoff with respect to the dominant climate change factors (e.g. temperature and precipitation) derived from the concept of climate elasticity are introduced. Results show that evaporation has a declining trend with a rate of 0.7 mm per decade, while runoff shows a weak increasing trend of 0.15 mm per decade over the global land surface. Analyses of the hotspots in the hydrological cycle indicate that the spatial distributions for evaporation and runoff are similar over many areas in central Asia, Australia, and southern South America, but differ largely in high latitudes. It is also found that, the evaporation hotspots in arid regions are mainly associated with the changes in precipitation. Our sensitive analysis suggests that the hydrological quantities show a rather complicated spatial dependency of response of the water cycle to the different climate factors (temperature and precipitation).