Changes of Snow-cover Area and Snowline Altitude in the Qilian Mountains,1997-2004

By using NOAA-AVHRR and EOS-MODIS data from May to August,1997-2004,spectrum characteristics of snow and ice are judged and analyzed,statistics of snow-cover area of three basins in the Qilian Mountains are made,and,by analyzing 8-year precipitation and altitude data,the snowline latitude-dependence is found.The result shows that the variation of snow-cover area from Jun to August was small,but it was large in May in the middle and east of the Qilian Mountains;on the contrary,temperature of snow-cover region was increasing,except for May;there was an increase in total precipitation of the Qilian Mountains from May to August.It is revealed that snow-cover area and snow line altitude change obviously with climate change of global and region,especially,in the middle section of the mountains.By analyzing artificial snowing data,it is demonstrated that artificial snowfall operation has a certain buffer function to snow ablation.