Establishing snowmelt runoff simulating model using remote sensing data and GIS in the west of China

Supported by Geographical Information Systems (GIS), snowmelt runoff simulation models have been built for the large-scale basin in the west of China. Digital Terrain Factors (DTF) were employed for dividing the basin. Using image-processing software, the problems of image correction and match between the satellite image and the images transformed from vector files have been resolved. Meanwhile, the thresholds of snow-pixel in images were achieved by means of a trial-and-error iterative process. Supervising classification techniques were utilized to determine the percentage of snow cover area in different zones and in the whole basin. The experimental watershed of the Qushenan (5286 km 2 ), in the upper reaches of the Yellow River was selected as a test basin. Snowmelt runoff models were developed for each sub-basin from which three vertical zones were simulated separately. The snowmelt runoff was computed by weighting coefficients. The results show that this approach is significant and practical.