Study On The Influence Of Climate Change On The Ecological Hydrological Process Of Tarim River Mainstream

Over the past century,global warming has led to the change of ecological hydrological process has become a hot topic for many scholars.Tarim River has the characteristics of rich natural resources and fragile ecological environment,and its ecological hydrological process is particularly sensitive to climate change.Based on the analysis of climate and ecological hydrological data,this paper reveals the characteristics and trends of climate and ecological hydrological processes in the river basin,and quantitatively depicts the ecological water demand line in the main stream of Tarim River.The main conclusions are as follows:(1)Based on M-W and M-K test,the main climatic factors in the Tarim River basin changed significantly in the past 1958-2014 years.The temperature decreased first and then increased.The mutation point was 1985,and the precipitation sequence showed a trend of increasing.The mutation point was 1986.The results of wavelet analysis show that there are many time scale periodic characteristics in the evolution process of the temperature and precipitation sequence,the temperature period is 28 years,22 years and 13 years,and the precipitation sequence cycle is 28,18,13 years.(2)The study of "Four sources and one main stream" runoff showed that the runoff of the Akesu River and the Kai-Kong River increased significantly,the rate was 6.10 × 108m3/10a and 3.67 × 108m3/10a respectively.The runoff abrupt points were all lagged behind the climate factor catastrophe point in 1992 and 1987,respectively.There was no obvious change in the Hetian River and the leaf of the Ye Qiang River,and the growth trend was not obvious.The flow of dry flow showed a obvious downward trend and the closer to the lower reaches,the less the amount of water,the greater the rate of runoff decreasing.(3)The results of wavelet transform and wavelet analysis show that the oscillation period of the Akesu River and the air temperature is more similar,the leaf of the Ye Qiang River and the Hetian River are similar to the precipitation,and the runoff from the open-hole river is similar to the temperature and the precipitation.Grey correlation analysis shows that the runoff sequence of "Four sources and one main stream" is all higher than that of air temperature.The runoff components of the Tarim River mostly come from snowmelt in the mountains.The increase of temperature leads to the aggravation of ablation,and the correlation between runoff and temperature is even higher.(4)Studies on the relationship between climate,runoff and ecological water demand show that:with the increase of temperature,runoff increases in the source area,and the climate affects runoff,but the change is lagging behind.The total runoff of the main stream is much larger than that of the natural vegetation outside the river,but the distribution is uneven in the year,and the water shortage is serious from March to June.The increase of temperature and precipitation will directly increase the coverage of vegetation to a certain extent,thus leading to the increase of ecological water demand.