Using satellite imagery to validate snow distribution simulated by a hydrological model in large northern basins

摘要

Owing to the scarcity of hydro-climatic data in high latitudes, most hydrological models are validated using only discharge data from the basin outlets. In view of the important contribution of snowmelt to northern river flows, there is a need to evaluate model performance in terms of the ability to simulate the seasonal pattern of change in the basin snow cover. The paucity of ground observations renders satellite information a suitable alternative. The moderate resolution imaging spectroradiometer (MODIS) global snow-cover product provided by the National Snow and Ice Data Center (NSIDC) offers one such tool to validate simulated snow coverage in rugged sub-arctic and boreal terrain. This study examines the usefulness of applying MODIS data to validate the hydrological simulation for two test basins: the Liard (275 000 km~2) and the Athabasca (133 000 km~2) Basins in Canada. Changing extent of snow cover simulated by the Semi-distributed Land Use-based Runoff Processes (SLURP) macro-hydrologic model was compared with MODIS imagery at four bi-weekly intervals in 2000 and 2001. The simulated patterns of seasonal snow-cover change are consistent with the remotely sensed information, with melt beginning from the lower elevations in the east where less snow was accumulated, to the higher elevations in the west bearing more snow. The overall results show the need and the usefulness of MODIS as a tool for validating snow distribution simulated by the hydrological model in large northern basins.