Snowmelt runoff modelling in a Himalayan basin with the aid of satellite data

The Himalayan basins have runoff contributions from rainfall as well as from snow and ice. In the present study a snowmelt runoff model (SRM) was applied to estimate the streamflow for Satluj basin located in the western Himalayan region. This model uses the direct input of remotely sensed snow-cover area (SCA) data for calibration and simulation. The SCA in the basin was determined using remote sensing data from the National Oceanic and Atmospheric Administration (NOAA) Advanced Very High Resolution Radiometer (AVHRR) and the Moderate Resolution Imaging Spectrometer (MODIS) onboard the Terra-Aqua satellite. In addition, daily precipitation and temperature data, as well as a Shuttle Radar Topography Mission digital elevation model (SRTM-DEM), were used to prepare the area elevation curves. The model was calibrated using the dataset for a period of 3 years (1996-1997, 1997-1998 and 1998-1999) and model parameters for streamflow routing were optimized. Using the optimized parameters, streamflow simulations were made for four years of data (i.e. 2000-2003 and 2004-2005). The accuracy of the streamflow verification was determined using different criteria such as shape of the outflow hydrograph, efficiency and difference in volume. The seasonal temperature lapse rates (TLRs) estimated from land surface temperature (LST) maps were used in the model and considerable improvement in simulation was observed. It was found that the overall efficiency increased when using varying TLRs.