Integrating two remote sensing-based hydrological models and MODIS data to improve water supply forecasts in the Rio Grande Basin

摘要

Remotely-sensed data can be used with modern hydrological models to provide effective water supply forecasts and to evaluate water resource management options. MODIS, on both NASA TERRA and AQUA satellites, is likely the optimum sensor for snow mapping because it has a best resolution of 250 m (two bands), it passes over daily, it is free for downloading, and it provides a logical transition from 1 km NOAA-AVHRR data. Its worth for snow mapping has been proven both in the Rocky Mountains of the United States and the Pyrenees of Spain. Still, research to solve automated and operational problems is ongoing, including corrections for the 'Bow Tie' effect, mapping in shaded and heavily vegetated areas, and using bidirectional reflectance distribution functions to retrieve snow albedo. As the remote sensing improvements are made, the data are used in the Upper Rio Grande basin for improvement of the snowmelt forecasting system. Remote snow-water equivalent site data are acquired through the Natural Resources Conservation Service SNOTEL system employing meteor-burst relay. These data can be used for early season (November-December-January) volumetric forecasts that increase water management flexibility. The MODIS-derived snow cover data are input to theSnowmelt Runoff Model (SRM) for generating daily streamflow forecasts over the entire melt season. Because snowmelt runoff is not significant throughout the entire basin, SRM outflow from snowmelt basins is linked to the Semi-distributed Land Use-basedRunoff Process (SLURP) model as an input. SLURP is a comprehensive distributed model now operating on the entire basin to assist in water management decision-making today and to evaluate future scenarios for improving long range planning. SLURP also usedremote sensing inputs to establish current landcover thoughout the basin, and to derive the Leaf Area Index for use in evapotranspiration algorithms. Examples of forecasts for the 2001-2004 in the Upper Rio Grande basin are presented.