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 1948–2006and 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).
This study aims to explore the interdecadal variation of South Asian High(SAH) and its relationship with SST(sea surface temperature) of the tropical and subtropical regions by using the NCEP/NCAR monthly reanalysis data from 1948 to 2012, based on the NCAR CAM 3.0 general circulation model. The results show that: 1) the intensity of SAH represents a remarkable interdecadal variation characteristic, the intensity of SAH experienced from weak to strong at the late 1970 s, and after the late 1970 s, its strength is enhanced and the area is expanded in the east-west direction.The expansion degree is greater westward than eastward, while it is opposite in summer. 2) Corresponding to the interdecadal variation of SAH intensity, after the late 1970 s, the divergent component of wind field has two ascending and three descending areas. Of the two ascending areas, one is located in the East Pacific, the other location varies with the season from the Indian Ocean in winter to the South China Sea and West Pacific in summer. Three descending areas are located in the north-central Africa, the East Asia and the Middle Pacific region respectively. 3) Corresponding to the interdecadal variation of SAH intensity, the rotational component of wind field at the lower level is an anomalous cyclone over the South China Sea and West Pacific in summer, while in winter, it is an anomalous cyclone over the Indian Ocean, and an anomalous anticyclone over the equatorial Middle Pacific. 4) Numerical simulations show that the interdecadal variation of SAH is closely related to the SST of the tropical and subtropical regions. The SST of Indian Ocean plays an important role in winter, while in summer, the SST of the South China Sea and West Pacific plays an important role, and the SST of the East Pacific also plays a certain role.
