STUDY ON MONITORING SNOW DISASTER IN LARGE AREAS SUPPORTED BY GIS AND RS
RS与GIS支持下的草地雪灾监测试验研究

Snow cover is an improtant factor influencing animal husbandry in winter in the north part of China. The relationship among grass height,snow cover area and snow depth is a key to determine the harmfulness of snow disaster.So.using NOAA/AVHRR image to get the snow cover area and using snowfall and topographic indices from DEM to measure snow depth will provide a practical way to monitor large area snow disasters. In this paper,Xilingol League in Inner Mongolia is selected as a study area,and following problems are studies:1.Clouds and snow surfaces have similar characteristics in both visible and infrared spectra.How to identify them in determining snow cover area is necessary but difficult. Multi-temporal composite technique in processing NOAA/AVHRR image is presented and testified as an effective method in this paper.2. Two topographic indices of wind sheltering fetch and relief from DEM are put forward,which are main factors influencing snow depth.Then the model of the relationship between snow cover depth and snowfall and above indices is built,and the distribution pattern of snow cover depth is revealed.3. By overlaying snow depth map and grass height map. the harmfulness of snow disaster is evaluated in the study area.