Abstract: According to the actual circumstance of catch flow irrigation,Tarim river valley was divided into three districts,Akesu territory with abundant water resource,the downstream region of Tarim river with serious water shortage and ecosystem flimsiness caused catching flow irrigation overmuch in its upriver,and the west natural area of Southern Xinjiang.By the data of temperature,rainfall,relative humidity,gale days,mean maximum wind speed and rain days with ≥0.1mm rainfall in the growth season (Mar.to Oct.) in 1961-2011 of 44 meteorological stations in valley area,environment and climate impact was contrasted and analyzed with climatic trend coefficient and Mann-Kendall test method.The results showed that the temperature,rainfall and relative humidity in three districts had a linear increase trend,which caused by warmer and rainy effect under the great climate background.As a result of unbalanced catch flow irrigation,their increase trend had a significant difference.The warmer rate was small in water plentiful area and more in water shortage area.Moreover the increase rate of precipitation and relative humidity was opposite,to be more in water plentiful area and little in water shortage area.The increasing of rain occurred mainly in 1980s with 22.29%-41.00%,but the relative humidity presented increasing tendency in 1990s with 4.109%-6.279%.M-K test presented large scale catch flow irrigation caused the relative humidity before the rainfall to happen abrupt change at 1973 synchronously in Tarim river valley,and the age of happened abrupt change for the rainfall had rather diversity on account of disproportion catch flow irrigation,Akesu area,the downstream region of Tarim river and the west of southern Xinjiang to be the summer of 1975,1979 and 1989 respectively.The temperature,precipitation and relative humidity had a consistent linear increasing trend in Tarim river valley,which was mainly affected by climate background.The difference of the linear rate was mainly related to local human activities with unbalanced water irrigation.The study results provided scientific basis for further recognizing on climate change and rational developping the water resources in Tarim river valley.

Key words: Tarim river valley, Growth season, Temperature, Precipitation, Relative humidity, Catch flow irrigation, Trend, M-K check