Rules Of Runoff Variation And Forecasting Of Xinjiang Aksu River Basin

Xinjiang is located in the northwest of China, and it suffers watershortage. The study on the change of the climate and the hydrologicalfeatures can not only provide technical support to the rational developmentand utilization of the water resource but also has important theoreticalsignificance and application value to guarantee the sustainabledevelopment of the economy. Through the research on the temperature,precipitation, evaporation, the annually runoff series and the characteristicsof the intergenerational and seasonal change of Aksu River basin inXinjiang over the period from1961to2000.We analysed the effect ofclimate change on runoff and we also use the artificial neural network tothe runoff prediction of the Aksu River basin. The main research contentsand results are as follows:(1)Methods of the linear trend, anomaly and accumulated anomaly areused to analysed the trend of the climatological data. Results show that thevariation rate of average annual atmosphere temperature of the Aksu Riverbasin in recent40years is0.305℃/10a and the temperature has the risingtendency remarkably. With the annual average0.582mm/10a variation, theaverage annual precipitation around that basin reflects a positive ascendingtrend in many years and rainfall amount in summer contributes a largeamount in annual precipitation. With the annual average of4.045mm/10avariation, the evaporation capacity shows a increasing trend after the firstdecreases, the evaporation capacity has a rising tendency allover the yearexcept winter.(2)Use Mann-kendall method to test the abrupt change of the climatein recent forty years. The conclusions are as follow: the temperature has aascending tendency after the average temperature had sudden change in1985. The precipitation has no abrupt point while the evaporation abrupt point was found in1994.(3)According to the analysis of the runoff data of the Aksu River basin,it is found that the runoff has a decreasing trend in waves and the drooprate is2.98×108m3/10a. The runoff has a remarkably decreasing tendencyand has abrupt point in the year of1963、1965、1972and1998.(4)The analysis on the correlation of the runoff and climate factors ofAksu River basin indicates that temperature can be an element to increasethe evaporation capacity. The linear correlation between temperature andrunoff, precipitation, runoff, evaporation and runoff, precipitation andevaporation is not significant.(5)Based on the impact of runoff and time series, we respectivelyestablished BP forecasting model. Both fitting accuracy of the runoffforecasting models are high, but the one based on time series is better thanthe one based on impact factors.