The Estimation of Snow Cover Distribution Using Satellite Data in the Cold Arid Leh Region of Indian Himalaya

Abstract

Snow cover is an important feature for the supply of freshwater and influences climatic hydrology at various altitudes, especially in mountain regions. Snow is a significant component of the environmental threat. In order to map and realize the extent of snow cover at high altitudes, continuous monitoring is therefore necessary. Data from satellite remote sensing helps to capture land cover and changes in land cover. The major intricacies in the snow cover mapping in the Leh region are the underlying vegetation, debris, and sparse snow. The Landsat OLI satellite data base methodology was developed to map the snow cover in the Leh region of the Indian Himalayas through NDSI (normalized difference snow index) to overcome such area specific issues. NDSI encompasses a reasonably good accuracy and can be used extensively because topographic shadows, water bodies and clouds can easily be misinterpreted as snow. It is capable of differentiating pixels of snow from pixels of cloud, debris, vegetation, and water. The NDSI was generated for snow mapping using Landsat OLI satellite images. Using the high reflectance of the snow in the blue band, misinterpreted water bodies were removed. NDSI was subsequently used month-wise to estimate the snow cover of the Leh region (Ladakh Union Territory of India). The findings of present study clearly indicate that the accuracy of the NDSI is reasonably appropriate for the estimation of the snow cover distribution over a wider area. It has been also observed that the snow cover in the study region has decreased over the years.