Abstract: The Qinghai-Tibet Plateau is renowned as the water tower of Asia and the third pole of the world. Changes in the water resources of the Qinghai-Tibet Plateau has a profound impact on the water resources security and people’s lives in China and its neighboring countries. The temporal and spatial changes of surface and groundwater resources in the Qinghai-Tibet Plateau from 1997 to 2018 are studied using linear tendency estimation, Mann-Kendall trend test and Pearson correlation coefficient method based on the data of Qinghai Water Resources Bulletin and Tibet Water Resources Bulletin. The results of the study indicate that: (1) water resources in the Qinghai-Tibet Plateau is extremely concentrated, mainly in Shannan, Nyingchi City, the Yarlung Zangbo River Basin and the river basins of southern Tibet. The south and east of Qinghai-Tibet Plateau boasts abundant water resources while the north and the west less. (2) From 1997 to 2018, the amount of surface water resources on the Qinghai-Tibet Plateau showed an insignificant upward trend, while the amount of groundwater resources (-16.64 billion m³/(10 a)) a significant downward trend. The change trends of water resources differed notably in spatial scale, with the surface water resources (9.83 billion m³/(10 a)) and groundwater resources (5.8 billion m³/(10 a)) in most areas of Qinghai Province in north Qinghai-Tibet Plateau displaying a significant upward trend, and surface water resources in most parts of the southern Tibet Autonomous Region an insignificant downward trend, groundwater resources a significant downward trend (-19.54 billion m³/(10 a)). (3) In recent years, the temperature in Qinghai-Tibet Plateau has had a very significant increasing trend, with the rising rate reaching 0.49 ℃/(10 a). The precipitation of Qinghai Province in the northern part of the Qinghai-Tibet Plateau showed a significant increase trend, while the southern part an insignificant downward trend. In conclusion, precipitation is the major factor that induces the changes of surface water resources and groundwater resources in the Qinghai-Tibet Plateau.

Key words: water resources, spatial distribution, temporal and spatial changes, climate change, influence factor, Qinghai-Tibet Plateau