Interrelationship of Climate Change, Runoff and Human Activities in Tarim River Basin

The temporal and spatial characteristics of climate change, dust storms and runoff in all the source areas and the mainstream of the Tarim River are analyzed based on observations in 13 meteorological stations (from 1961 to 2000) and 8 hydrologic stations (from 1957 to 1998) over the Tarim River basin. The water consumption influencing index, which quantifies the impact intensity of human activities, is set up, and the impacts of climate change and human activities on the runoff, even the ecological environment are studied. The results show: (1) Although the runoff over the source areas didn't change obviously since 1950's, but the amount of water entered the mainstream of the river from these source areas obviously decreased, and human activities is the main cause. (2) The water consumption influencing index analysis shows an increasing trend, which reflects the impact of human activities to some degrees, and the impact of human activities in the middle reaches of the river is greater than that in the upper reaches. The impact of human activities was most obvious during the period from the 1970's to the imd-1980's, and slowed down in recent 10 years. (3) In 1990s, temperature and precipitation increased over the river basin. The increasing amplitude of temperature increases from the source areas to the lower reaches of the river. In Aksu (in the source area), the increasing amplitude is the smallest for temperature and the biggest for precipitation. (4) Since the 1990's, the number of dust storm days, the number of floating-dust days and the number of strong-wind days in the river basin obviously decreased. These changes could be attributed to the extending of oasis. (5) Precipitation at Tiekanlik (at the lower reaches) decreases, instead of increasing, and the number of dust storm days increases. It should be paid attention by the related departments.