Characteristics of winter mass balance of Glacier No.1 at the headwaters of the Urumqi River, Tianshan Mountains

This study analyzes the response of glacier to climate change during the past 49 years in Urumqi River source region, the Tianshan Mountains of China. The temporal and spatial variations of winter mass balance (bn-w) at different time scales were analyzed to identify their response to climate change during 1988–2006 (The observation of winter mass balance observation began in 1988) on the Glacier No.1 at the headwaters of the Urumqi River, Tianshan Mountains, China. The winter accumulation shows a significantly decreasing trend. The results show that the cumulative values on Glacier No.1 is 2,202 mm water equivalent during 1988–2006 and the mean values is 116 mm a⁻¹. Furthermore, the trend analysis of the winter mass balance indicates a rapid decrease since 1990, and the mean mass balance is only 79 mm a⁻¹ during 1997–2006. Winter mass balance correlates well negatively with the total evaporation from September to April (r = −0.68, α = 0.01), and positively with the total precipitation from September to April (r = 0.74, α = 0.01). However, winter mass balance shows a weak correlation with mean minimum air temperature during September to April (r = −0.35), and runoff on September (r = −0.13).