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Climate change and hydrologic process response in the Tarim River Basin over the past 50 years are the tocus of more and more researchers' attention. In this paper, both temperature and precipitation time series were found to present a monotonic increasing trend using nonparametric tests. Noticeably, a significant step change in both temperature and precipitation time series occurred in 1986. By contrasting the trends of natural water process in headstream and mainstream, we found that it was anthropogenic activities not climate change that caused the river dried up and vegetation degenerated in the lower reaches of Tarim River. The results of gray correlation analysis show that the runoff of higher latitude distributing river is more closely associated with winter snow stocking, while that of lower latitude is more closely related to summer temperature. Runoff in the headstream is more sensitive to precipitation, while that in the mainstream is more sensitive to evaporation. The strong evaporation caused by increasing temperature weakened runoff to some extent in spite of the fact that precipitation increased over the past 50 years. [ABSTRACT FROM AUTHOR]

Water resources efficient utilization is the key to ecological improvement and economic development in Tarim River Basin. It is necessary to analyze the water resources utilization and its variation tendency in the whole river basin. Based on the monitored data and formation at eight meteorological stations and fifteen hydrological stations, the method of time series, regression analysis are applied to analyzing the water resources utilization and variation trend in the headstreams and mainstream areas especially in recent 10 years . The quantitative results indicate that inflows of the headstream areas have an increasing trend to different extent in the past 40 years. The runoff increasing trend is more significant from 1994 to 2002, which show the water resources condition in the headstreams is at an advantage. However, under the condition of water increase with the volume of 25×108 m³ in headstreams in recent 10 years, the mainstream water flowing from the headstreams has increased less than 0.9985×108 m³. In addition, the runoff at the different hydrologic stations along the Tarim River has a significant linear decreasing trend. It is shown that the degraded trend of ecological environment in the mainstream areas hardly changes even if the Tarim River Basin is in the special water period for ten consecutive years. [ABSTRACT FROM AUTHOR]