摘要
Climatic change has significant impacts on snow cover in mid-latitude mountainous re- gions, in the meantime, spatial and temporal changes of snow cover and snowmelt runoffs are con- sidered as sensitive indicators for climatic change. In this study, the upper Heihe Watershed in the Qilian Mountains was selected as a typical area affected by snow cover and snowmelt runoffs in northwestern China. The changes in air temperatures, precipitation, snowfall and spring snowmelt runoffs were analyzed for the period from 1956 to 2001. The results indicate that climatic warming was apparent, particularly in January and February, but precipitation just fluctuated without a clear trend. The possible changes of snowmelt runoffs in the upper Heihe watershed in response to a warming of 4℃ were simulated using Snowmelt Runoff Model (SRM) based on the degree-day factor algorithm. The results of the simulation indicate that a forward shifting of snow melting season, an increase in water flows in earlier melting season, and a decline in flows in later melting season would occur under a 4℃ warming scenario.
Climatic change has significant impacts on snow cover in mid-latitudemountainous regions, in the meantime, spatial and temporal changes of snow cover and snowmeltrunoffs are considered as sensitive indicators for climatic change. In this study, the upper HeiheWatershed in the Qilian Mountains was selected as a typical area affected by snow cover and snowmeltrunoffs in northwestern China. The changes in air temperatures, precipitation, snowfall and springsnowmelt runoffs were analyzed for the period from 1956 to 2001. The results indicate that climaticwarming was apparent, particularly in January and February, but precipitation just fluctuatedwithout a clear trend. The possible changes of snowmelt runoffs in the upper Heihe watershed inresponse to a warming of 4℃ were simulated using Snowmelt Runoff Model (SRM) based on thedegree-day factor algorithm. The results of the simulation indicate that a forward shifting of snowmelting season, an increase in water flows in earlier melting season, and a decline in flows inlater melting season would occur under a 4℃ warming scenario.
