Impacts of climate change on headstream runoff in the Tarim River Basin

The impacts of climate change on annual runoff were analyzed using hydrologic and meteorological data collected by 8 meteorological stations and 15 hydrological stations in the headstream of the Tarim River Watershed from 1957 to 2005. The long-term trend of climate change and hydrological variations were determined by parametric and non-parametric tests. The results show that the increasing scale of precipitation is less than the scale of rising temperature. The change and response of hydrological process have their own spatial characteristics in the tributaries of a headstream. Precipitation and temperature do not increase simultaneously in the hydro- and meteo-stations located in the headstream. The temperature and runoff displayed certain relations, and a relationship also existed between precipitation and runoff. The annual runoff of the Aksu and Kaidu rivers was consistent with an increasing trend in temperature and precipitation during the past 50 years; temperature increases have a greater effect on annual runoff. These results suggest that with the increase of temperature in the Tarim River Watershed, the glacier in the headstreams would melt gradually which results in runoff increase in several headstreams. However, glacier meltwater would be exhausted due to continual glacier shrinkage, and the increased trend of runoff in the headstreams would also slow or lessen. Thus, regional water resources shortage problems are still serious and have become a major feature in the Tarim River Watershed.