The Drawing Of Snow Information In Xinjiang Based On MODIS Data And Its Application

Because of MODIS predominant space and spectral differentiate rate,it's has been broadly applied to various field,in the aspect of snow monitoring,MODIS has been successfully using a normalized difference snow index(NDSI)to provide global automated binary maps of snow cover.The NDSI is a spectral ratio that takes advantage of the spectral difference of snow in short-wave infrared and visible spectral bands ,although it has higher precision,it can only discern one pixel to snow or other features,can not satisfy accurate drainage basin snow cover mapping and snow parameter extracting. This study take the north of Xinjiang as research area, using linear spectrum mixing model abstracting snow's proportion in a pixel, then establish connection with NDSI,evaluating whether NDSI can be used to estimate the fraction of snow within a 250m pixel and thereby enhance the use of NDSI approach in monitoring snow cover. The result show that they have good linear relation,the mean absolute error of 25 ground true measuring point is 0.06. Besides,this study has analyzed the correlativity of each band with snow depth, and compared snow true measuring spectrum with image spectrum, picked out the most sensitive band to snow depth, build inversion snow depth model. At last, integrating the snow drawing measure and true surveying data in the field, analyzing the snow distributing character, snow change in annual and season at length.