Regional climate change and its effects on river runoff in the Tarim Basin, China

Abstract

Abstract:The hydrological response to climate change in the Tarim River Basin was investigated by analysing the hydrological, temperature and precipitation data of the past 50 years. The long-term trend of the hydrological time-series, including air temperature, precipitation, and streamflow, was examined by using both parametric and non-parametric techniques and the plausible association between streamflow and climate change by the method of grey correlation analysis. The results show that the study area became warmer in the last few decades. The air temperature experienced a significant monotonic increase by 5%; the precipitation showed a significant decrease in the 1970s and then a major increase in the1980s and 1990s, with average annual precipitation up by 6Ð8 mm per decade. A step change occurred in both temperature and precipitation around 1986, with mean temperature and precipitation increasing from 6Ð7°C and 146 mm before 1986 to 7Ð3°C and 180 mm respectively after 1986. The temperature has risen by nearly 1°C over the past 50 years, possibly resulting from the impact of global climate change. Streamflows in the Aksu River and the Yarkant River have shown a significant (P < 0Ð05) tendency of increase. This is particularly the case for the Aksu River. The coefficients of streamflow increase in the Aksu and Yarkant Rivers are 0Ð41 and 0Ð13 respectively. The results of grey correlation analysis show that in the Aksu River, which is located in the northwest of the basin, the impact of precipitation on streamflow is much greater than that of temperature. However, in the Hotan River, which is located in the southwest of the basin, the impact of temperature on streamflow is much greater than that of precipitation. This is likely to be related to the geographic distribution of the headstreams of the rivers.

The Nonlinear trend of runoff and its response to climate change in the Aksu River, western China

“…Therefore, there are conceivably close relationships between runoff and a set of regional climate factors, especially temperature and precipitation. This perception is supported by the results of some previous studies for the headwaters of the Tarim River Basin (Xu et al, 2004;Jiang et al, 2005;Chen et al, 2006;Zhang et al, 2008;Xu et al, 2009b). From the physical mechanism, the temperature mainly influences the runoff by glacier melt and snowmelt while Notes: AR -annual runoff, AP -annual precipitation, PFS -precipitation in flood season, AAT -average annual temperature, ATSP -average temperature in spring, ATSU -average temperature in summer, ATA -average temperature in autumn, and ATW -average temperature in winter.…”

Response of hydrological processes to land‐cover and climate changes in Kejie watershed, south‐west China

“…The simulation results of Singh and Bengtsson (2004) showed that increasing temperatures caused decreases in streamflow in winter, summer, and autumn; however, streamflow increased in spring in western Himalayan rivers. Chen et al (2006) reported significant and subtle increasing trends and slight decreasing trends in streamflow at different headwaters of the Tarim River when temperature and precipitation increased.…”

“…An inflection point (in 1986) was identified through visual observation, and this coincides with the Tarim River Basin in north-west China (Chen et al, 2006). The annual temperature of two meteorological stations in Yunnan Province (Tengchong Station 180 km away from Longyang Station and Kunming Station about 580 km away from Longyang Station) were tested to show the trend in temperature change in Baoshan.…”

“…There is a conviction that recent regional changes in temperature have had discernible impacts on physical and biological systems (IPCC, 2007). Recent studies show that climate change has altered water flows and resources in river basins (Chen et al, 2006;Rees and Collins, 2006). Current research into the effects of land-cover/climate changes on hydrological processes and water-related environmental services, and who are the winners and losers on different scales, is insufficient for formulation of useful policies (Calder, 2007;Noordwijk et al, 2004).…”

Variability of modeled runoff over China and its links to climate change

“…For instance, increasing annual mean runoff was observed in the East River and the Yangtze River basins, South China (Zhang et al 2015;Zhang et al 2006). In Northwest China, runoff also increased during the past 50 years, with a step-like change in precipitation at approximately 1986 (Chen et al 2006). In contrast, in the Yellow River basin, runoff has been decreasing in recent decades (Zhang et al 2009).…”