The Study Of Runoff Change And Hydrological Response To Climate Change In Aksu River Basin, China

Along with the Copenhagen world climate conference has convoked in 2009, the global climate change not only is scientific research hot point, but also become social and even political issue currently. With the global warming, the climate in Aksu River Basin has been warming tendency over the past 50 years, and climatechange will have an impact on hydrology and water resources.This paper based on the meteorology and hydrology data from two hydrologic station(the Shaliguilanke and Xiehela)in 1957-2008, Uses many mathematic statistics methods and models to analysis the spatio-temporal distribution,the cycle change,the continuous about temperature, precipitation and runoff; and to explore the main factors which impact runoff change, simulate and forecast runoff.On this basis, this paper studies runoff responses to climate change process of Aksu River. The mostly conclusion as follows: There is an upward trend about temperature in Aksu River Basin, the increasing trend rate arrived at above 0.3℃/10a, most of month show an upward trend, the biggest increase in fall and winter; the warming become more obvious after 90 years, there was a mutation in 1984 thereby from low to high, and its primary cycle change is about 13a. The precipitation distribution during the year is uneven, mainly accumulated in the summer, water and warm appeares at the same period, the maximum precipitation appeared in July to August, the minimum precipitation in November to December yearly. The maximum precipitation of continuous four months appeares in June to September and in May to August of two stations, accounting for 66.99% and 64.21% of many years; there is a mutation in 1986 thereby from less to more. There is about 19a primary cycle in large-scale and 6a in small-scale.The runoff has an increasing trend, its inter annual changes is relatively stable,the C vof two stations is 0.20 and 0.15, which reflects Aksu River is a snow melt and rain water mixed supplies river. There is an collision increasing trend in 1957-2008, the tendency rate of two stations respectively are 0.283×10~8m~3/a and 0.184×10~8m~3/a.The annual runoff become stable and the minimum stable years arrives 35 years. The non-linear trend is clearly in 16 (2~4) years, 8 (2~3) years and 4 (2~2) years of scales respectively, with the reducing scale, the annual runoff series presents more fluctuations, but it appeares increasing on the whole. Over the past 52 years, the high runoff year sumed to 12 years which appeared continuously in the late 90s, with a longest duration of 7 years, while the low runoff year mostly had a total of 12 years, the number of normal runoff year accounted for 54%, and mixture appeared with low runoff years. There is mutation in 1994, the amount of runoff volume increases distinctly after this spot. There is an about 25a main cycle for annual runoff.The duration time of daily flood peak and the maximum peak become decrease in 2002, 2003 and 2008,it is deleterious to Trim River.The correlation of runoff with temperature is greater than the correlation with rainfall. Runoff and temperature, precipitation is not synchronization and had certain lag. The pairs of cumulative curve of annual runoff and annual precipitation of deep appeares linearly increasing trend, two stations correlation coefficients are 0.996 and 0.965, and so annual runoff series have very high consistency. The correlation coefficient of runoff and NAO is low; there is not significant association between runoff and NAO. This paper uses five models to simulate and predict runoff, the results showed accuracy in line with short-term forecasting accuracy requirements, and simulates well about the measured value and predicted value. The increase trend is not obvious in the next few years of the Aksu annual runoff.