Snow covers monitoring using MODIS data (Case study: Ghara-Chay Watershed, Hamedan, IRAN)

Snow is one of the major sources of water in most part of the world. In the hydrology and climate studies, determination of the snow cover surface area is one of the most important parameters. One of the tools that have a lot of use in the watershed snow cover survey and hydrological properties is remote monitoring by satellite images. In this research, we used the MODIS images and NDSI index for mapping of snow cover. We calculated the NDSI index and we used the threshold in 2, 4 and 6 bands for discrimination between snow and other wet lands. After calculating NDSI, the snow-covered surface was then interpolated for days without satellite images by Malcher algorithm. The results showed that the NDSI index assistant with the thresholds and Malcher algorithm had good performances in determining the snow cover surface area. In this research, the average error of snow cover maps, including the error of NDSI index is less than 20%. At the end, we calculated the snow cover with Malcher algorithm and NDSI index for 2006-2007.