Study On Runoff Of Manas River Basin Response To Climate Change

The global climate is warming at an unprecedented rate in past century, a range of issues have been triggered such as melting of glaciers, extreme weather, food production, rising sea levels, species extinction and air pollution, this issues is more and more cause for concern. Manas river originates from glacier area of YiLianHabi Er Ga mountains that in the northern slope of Tianshan Mountain, it is the largest river which has the largest number of glaciers in Junggar Basin, the length of river is 324km, the area of glacier is 692.5km2. As a typical inland arid area in Xinjiang River, study of climate change impact on runoff change plays a vital role on local ecological environment, agricultural production and sustainable development.This article takes Manas river as the model research basin, uses the hydrology model simulation method, uses including Xin'an river model with the thaw structure to make a simulation of the runoff processes of the research area in 1958～1987, then to carry on the analysis and the examination to its result. The analogue result basically conforms to the trend of the actual runoff process.In order to study the variation trend of the basin climatic, we use the research area actual hydrological data (actual daily average temperature and precipitation data) to carry on the analysis to the climate character of the research area, to obtain the temperature rise tendency of the Kensiwate hydrological station in Manas river basin in 30 years. The results are:during 1958～1979, the temperature assumed the tendency which presents with slow undulation drop, during 1980～1987, there was a marked rise in temperature, the temperature average ascension scope reached 1.2℃; the precipitation assumes drop tendency, during 1958～1972, precipitation change was not obvious, during 1980～1987, precipitation reduced gradually, but the drop scope was small. This article selects the research area data in 1983～1987, using distributional hydrology model constructed to simulate the runoff forming process under different climate scenes. The simulation plan is:the precipitation is invariable, and the daily temperature increases 1℃and 2℃; the temperature is invariable, and the daily precipitation reduces and increases 20%.The results indicates that under the situation the temperature elevates every degree Celsius, the annual runoff during 1983～1987 separately increases 29.80%,22.72%,28.58%,43.26% and 36.54%, the average increase range is 32.18%; under the situation the temperature elevates every two degrees Celsius, the annual runoff during 1983～1987 separately increases 57.72%,50.26%,61.79%,81.75% and 24.33%, the average increase range is 55.17%. When the precipitation increases 20%, the annual runoff change during 1983～1987 respectively is 10.98%,-3.35%,5.97%,11.20%,16.22%; When the precipitation reduces 20%, the annual runoff change respectively is 1.01%,-14.85%,-8.26%,6.21%,2.01%.The runoff of river basin in temperature changing is positively response, namely with a temperature rise, the runoff presents the trend of increased, and the influence of precipitation increase or decrease on runoff is small, the total quantity of annual runoff does not change significantly. From this study, we obtain that in Manas river basin the annual runoff process has obvious response to the change of temperature than to the precipitation.