Statistical analysis of stream discharge in response to climate change for Urumqi River catchment, Tianshan Mountains, central Asia

Understanding the impact of climate change on water resources is essential to sustainable development. Urumqi River, a medium-size headwater catchment in the Tianshan mountains, was chosen to evaluate the impact of climate change on its discharges, where impacts of human activities on water are negligible and the influence of glacier melt is minor as far as the mountainous outlet is concerned. Analysis of the time series of temperature, precipitation and river discharge of the hydrological station at the mountainous outlet from 1959 to 2006 was carried out using different statistical methods, including linear regression, Mann–Kendall test and wavelet analysis. Although both temperature and precipitation show a significant upward trend with a gradient of 0.02 °C/y and 2.08 mm/y, respectively, there is no significant rising trend in the stream discharge. The reasons are attributed to the hysteresis and buffering effects of groundwater in conveying the change from precipitation to stream discharge. Common short periods of less than 8 years exist in the three time series, which is a common trend in NW China. Precipitation has stronger influence on stream discharge than air temperature throughout the 48 years of instrumental records in the Urumqi River catchment.