MONITORING OF SEASONAL SNOW COVER IN YAMUNA BASIN OF UTTARAKAHND HIMALAYA USING REMOTE SENSING TECHNIQUES

Himalaya has one of the largest resources of snow and ice, which act as a freshwater reservoir for all the rivers originating from it. Monitoring of these resources is important for the assessment of availability of water in Himalayan rivers. Therefore a study was taken up with the objective to monitor snow cover in the sub-basins of Ganga. Snow cover was monitored for Yamuna basins for beginning from 2003 by using the algorithm based on Normalized Difference Snow Index. These basins are selected on the basis of different climatic zones. The snow accumulation and ablations curves are different for each basin, depending upon climatologically sensitive zones and altitude distribution of the basin. NDSI Algorithm was used to generate snow cover products in every five and ten daily intervals. The present result gives the current status of Snow cover area of five and ten daily products. The AWiFS data of Resourcesat satellite was analyzed to estimate snow extent. The snow cover was monitored for a period between October and June from year 2003 to 2010 A total 156 AWiFS scenes were analyzed during this period. Snow cover was not monitored during June-September due to cloud cover. The various parameters as maximum and minimum radiances, mean solar Exo-atmospheric spectral irradiances in the satellite sensor bands, satellite data acquisition time, solar declination, solar zenith and solar azimuth angles, mean Earth-Sun distance was used to estimate reflectance. Sensitivity analysis has shown that a NDSI value of 0.4 can be taken as a threshold to differentiate between snow and non-snow pixels. Results obtained during this investigations suggest presence of snow cover in different months vary from October to June