Monitoring of snow cover distribution and reflectance in the river basins of different snow climatic zones of North-West Himalaya
Student name: Mr Dharmesh Kumar Singh
Guide: Dr P K Joshi
Year of completion: 2013
Host Organisation: Snow & Avalance Study Establishment, Chandigarh
Supervisor (Host Organisation): Dr H S Negi
Abstract: The snow cover in the Himalayas occurs and exists depending on the terrain and climatic
conditions of the region. Snowfall varies by time and location, including geographic latitude,
elevation and other factors which affect weather in general. The dates (time) of occurrence
and disappearance and the duration of snow cover are important factors for human
activities. In addition, the highly reflective nature of snow combined with its large surface
coverage makes snow an important component of the Earth’s radiation balance. Hence,
mapping of snow cover area (SCA) and reflectance of snow cover is an important parameter
for various climatological and hydrological applications. The aim of the study is to monitor
the SCA and reflectance in Beas, Bhaga, Nubra basins of north-western Himalaya in order to
understand the snow cover pattern and changes in the last approximate one decade for three
different snow climatic zones. The MODIS 8-days (Surface reflectance product) average
snow products were used for the monitoring of snow cover area and spectral reflectance.
Thirteen years’ time series data between March 2000 and December 2012 were analysed.
The average annual snow cover area (SCA) for all the three basins was found to be
approximately constant between 2000 and 2012. However, slightly increasing trends were
observed in SCA for Bhaga and Beas basins while a small decreasing trend was observed for
Nubra basin. Further season wise SCA shows during winter months (NOV-APR) the average
SCA has decreased in Nubra basin in last one decade, whereas it was approximately
constant for other two basins. During summer season (MAY-OCT) the average SCA has
shown increasing trend in all the basins. The study shows that Bhaga basin remains
maximum snow covered (100%) during winter period, whereas for other two basin SCA was
found maximum up to 80-90%. Further it was observed that in Beas basin maximum area
remains snow free at late summer (SCA<=2%), whereas for Nubra it remains (SCA<=20-
50%) snow covered even after ablation period. This support the fact that maximum area in
Nubra basin is glaciated / permanent snow covered in comparison to Beas and Bhaga basin.
Further high albedo throughout the year in Nubra basin shows low temperature in the
region. A lot of variation/fluctuations in SCA of Beas basin were observed in comparison to
other Bhaga & Nubra basins. These fluctuations have been verified using increasing
reflectance in visible band (Green) once the snow fall taken place. In addition SWIR band
reflectance remains low (<20%) once the snow cover appear in basin.
Key words: - MODIS, Surface reflectance, NDSI, Snow cover area.
