Hydrological Regime of the Karuxung Watershed in North Himalayas
喜马拉雅山北坡卡鲁雄曲径流与气候变化

Water supply of the Karuxung watershed is mainly from melt water and rainfall, therefore both climate warming and precipitation increasing have positive impacts on runoff. Mann-Kendall trend analysis, the Sen's slope estimate and correlation analysis are employed to analyze data from Wengguo hydrometric station and Langkazi meteorological station. The results indicate that runoff, air temperature, precipitation and evaporation all have showed significant upward trends. Of which runoff change is most sensitive to climate change, especially during fall and winter. It is concluded that more trends are observed than are expected to occur by chance. In recent 20 years, the annual mean temperature has increased dramatically with a rate of 0.34 oC every 10 years, which is higher than that of Xizang (Tibet) region which is 0.26 oC every 10 years, and the extremely high temperatures all appeared in the 1990s. For the temperature, the latter 10 years is 0.5 oC higher than the former 10 years, whereas the runoff increased by 26%. Different periods have different growth extents. October to February, July to September and March to June increased by 44%, 27% and 24%, respectively. During ablation period, the runoff change is affected mostly by climate change from April to June, whereas the runoff is affected by climate and precipitation jointly when monsoon comes, and the rainfall influences the runoff with uncertainty. During non-ablation period, runoff change is more obvious for it is influenced by the former months, and its key supply is base flow.