Abstract: Glacier and snowmelt water are precious resource for inland district in Northwest China.This paper applied the snowmelt runoff model (SRM) in the Koxkar glacier basin, southwestern Tianshan Mountains in China. Based on the field observation and MODIS snow cover product over the research basin, the parameters of the SRM were determined. The degree-day factor is very sensitive and important in the model, therefore this parameter was calibrated monthly by the runoff data in 2007 and 2008. For 2005 and 2006, the model result is acceptable compared with SRM model results applied in 80 catchments for 25 countries. Hence the model is suitable for the glacier cover basin. The response sensitivity of basin runoff to climate change has been done. Temperature is the control factor. Under the climate background of 1℃, 2℃ and 4℃ temperature rising, the runoff of Mar.-May increases by 48%, 155% and 224% respectively, and the runoff of May-Oct. increases by 30%, 77% and 104%. The runoff process of the basin also changes under the increasing temperature of 4℃and precipitation of 20%, the peak time of snowmelt runoff shifts from middle May to late April, and the peak of snowmelt runoff increases from 6 m3/s to 17 m3/s, and the peak of glacier runoff increases from 14 m3/s to 28 m3/s.

Key words: Tianshan Mountains, degree-day factor, snowmelt runoff model (SRM), Keqicar Glacier, climate change