Abstract:On the basis of the CLM3 (Community Land Model 3) simulated soil and c anopy evaporation, the climatology and spatial temporal variations of the land w ater resource in China are investigated. The distribution of annual mean water r esource is similar to that of annual mean precipitation in China, with a patt ern of the largest in the south of Yangtze River and the smallest in Xinjiang, d ecreasing gradually from southeast to northwest. The total evaporation shows a c lose relationship with the precipitation, with the high evaporation region locat ed in south of 35°N and the low evaporation area in north of 35°N, especially in the northwest, where mean annual evaporation may be below 50 mm. From the distr ibution of evaporation index, we can see a different pattern, in which the high regions are located in northern China and the low regions are in southern China. Analyses of the linear trend show that the land water resource has decreased in most regions of China including northern China north of 35°N except northern T ibetan Plateau, western Xinjiang Autonomy Region and Hetao areas, while increased in the Tibetan Plateau and southern China during the past twenty years. The dec reased (increased) atmospheric precipitable water is generally consistent with t he downward (upward) trend of the land water resource and the variation of the p recipitable water is considered as an important cause of water resource change.