Snowmelt run-off model (SRM) based on degree-day approach has been employed to evaluate the change in snow-cover depletion and corresponding streamflow under different projected climatic scenarios foran eastern Himalayan catchment in India. Nuranang catchment located at Tawang district of ArunachalPradesh with an area of 52 km^2 is selected for the present study with an elevation range of 3143–4946 mabove mean sea level. Satellite images from October to June of the selected hydrological year 2006–2007were procured from National Remote Sensing Centre, Hyderabad. Snow cover mapping is done usingNDSI method. Based on long term meteorological data, temperature and precipitation data of selectedhydrological year are normalized to represent present climatic condition. The projected temperatureand precipitation data are downloaded from NCAR’s GIS data portal for different emission scenarios(SRES), viz., A1B, A2, B1; and IPCC commitment (non-SRES) scenario for different future years (2020,2030, 2040 and 2050). Projected temperature and precipitation data are obtained at desired locationby spatially interpolating the gridded data and then by statistical downscaling using linear regression.Snow depletion curves for all projected scenarios are generated for the study area and compared withconventional depletion curve for present climatic condition. Changes in cumulative snowmelt depth fordifferent future years are highest under A1B and lowest under IPCC commitment, whereas A2 andB1 values are in-between A1B and IPCC commitment. Percentage increase in streamflow for differentfuture years follows almost the same trend as change in precipitation from present climate under allprojected climatic scenarios. Hence, it was concluded that for small catchments having seasonal snowcover, the total streamflow under projected climatic scenarios in future years will be primarily governedby the change in precipitation and not by change in snowmelt depth. Advancing of depletion curves fordifferent future years are highest under A1B and lowest under IPCC commitment. A2 and B1 values arein-between A1B and IPCC commitment.
Volume 129, 2020
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