Characteristics and influencing factors of runoff changes in the upper Shule River basin from 1954 to 2016北大核心CSCD

River runoff is an important water resource in the arid region of northwest China. Under the back? ground of climate change，the exploration on change characteristics and influencing factors of river runoff is of great significance for understanding the law of river hydrological change. Based on the daily discharge of Chang? mabao hydrological station，the observation materials from meteorological stations and radiosonde stations，and the first and second Chinese glacier inventory，the variation characteristics and possible influencing factors of runoff in the upper Shule River were systematically analyzed by using the linear trend，empirical mode decompo? sition and hierarchical multiple regression. The results show that the annual runoff of the upper Shule River showed a significant increasing trend during 1954-2016，with a rate of 1. 00×108 m3·（10a）-1. Both runoff in flood period and non-flood period also showed a similar increasing trend. The runoff suddenly changed in 1999 and had two oscillation periods of about 15a and 7a，among them the 15a oscillation period was the most signifi? cant. Both cumulative positive temperature and precipitation were the main climatic factors affecting the runoff in the upper Shule River，which can explain more than 80% of the runoff change. There was a significant posi? tive correlation between the summer runoff in the upper Shule River and the height of 0 ℃ layer. It means that the height changes of 0 ℃ layer can be used to predict the runoff change of the river in flood period，which provides an important reference for evaluating the runoff change of glacial melt recharge rivers in the arid re? gion of northwest China. From 1966 to 2006，the ice volume in the upper Shule River basin decreased by about 5. 77 km3，indicating that glacier changes play a crucial role in the change and regulation of runoff in the basin. © Journal of Glaciology and Geocryology 2022.

Characteristics and influencing factors of runoff changes in the upper Shule River basin from 1954 to 2016

River runoff is an important water resource in the arid region of northwest China. Under the background of climate change， the exploration on change characteristics and influencing factors of river runoff is of great significance for understanding the law of river hydrological change. Based on the daily discharge of Changmabao hydrological station， the observation materials from meteorological stations and radiosonde stations， and the first and second Chinese glacier inventory， the variation characteristics and possible influencing factors of runoff in the upper Shule River were systematically analyzed by using the linear trend， empirical mode decomposition and hierarchical multiple regression. The results show that the annual runoff of the upper Shule River showed a significant increasing trend during 1954—2016， with a rate of 1.00×10⁸ m³·（10a）^-1. Both runoff in flood period and non-flood period also showed a similar increasing trend. The runoff suddenly changed in 1999 and had two oscillation periods of about 15a and 7a， among them the 15a oscillation period was the most significant. Both cumulative positive temperature and precipitation were the main climatic factors affecting the runoff in the upper Shule River， which can explain more than 80% of the runoff change. There was a significant positive correlation between the summer runoff in the upper Shule River and the height of 0 ℃ layer. It means that the height changes of 0 ℃ layer can be used to predict the runoff change of the river in flood period， which provides an important reference for evaluating the runoff change of glacial melt recharge rivers in the arid region of northwest China. From 1966 to 2006， the ice volume in the upper Shule River basin decreased by about 5.77 km³， indicating that glacier changes play a crucial role in the change and regulation of runoff in the basin.