|Gomez-Landesa, Enrique - USDA-ARS|
Submitted to: Hydrological Processes
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: January 30, 2001
Publication Date: N/A
Interpretive Summary: Very little conventional information exists on snow resources in the Spanish Pyrenees although these mountains provide significant snowmelt runoff for water supplies and power generation. A new source of data and sophisticated analysis techniques were necessary to generate timely runoff predictions to the power companies to assist in their systematic planning. A subpixel analysis technique was developed to allow application of the satellite data to very small basins, and the resulting snow cover data were fed into the Snowmelt Runoff Model for forecasting of flows on 42 basins. The forecasts permitted the power companies to make more logical decisions in their seasonal planning. The results are applicable to similar applications in the U.S. including planning for irrigation water supplies.
Technical Abstract: The Snowmelt Runoff Model (SRM) is being used to simulate and forecast the daily discharge of several basins in the Spanish Pyrenees. These results are being used by hydropower companies of Spain for improved management of water resources. We describe a method for snow mapping using data fro the AVHRR (Advanced Very High Resolution Radiometer) instrument on board NOAA (National Oceanic and Atmospheric Administration) polar orbiting satellite and a procedure to retrospectively estimate the accumulated snow water equivalent volume with the SRM model. A linear combination of NOAA channels 1 and 2 is used to obtain a snow cover image in which the product is the percent of the snow covered area in each pixel. Real-time snowmelt forecasts are being carried out with the SRM model using snow covered area as an input. Even in basins with a total absence of historical discharge and meteorological data, the SRM model provides an estimation of the daily snowmelt discharge. Integrating the forecasted streamflow over the recession streamflow, the snowmelt volume is obtained as a function of time. This function converges asymptotically to the net stored volume of water equivalent of the snowpack. Plotting this integral as a function of time, it is possible to estimate for each basin the already melted snow water equivalent (SWE) and the SWE remaining in storage, at any moment of the snowmelt season.