Submitted to: World Resources Review
Publication Type: Peer reviewed journal
Publication Acceptance Date: 1/20/2003
Publication Date: 4/1/2003
Citation: RANGO, A., GOMEZ-LANDESA, E., BLEIWEISS, M., HAVSTAD, K.M., TANKSLEY, K. IMPROVED SATELLITE SNOW MAPPING, SNOWMELT RUNOFF FORECASTING, AND CLIMATE CHANGE SIMULATIONS IN THE UPPER RIO GRANDE BASIN. WORLD RESOURCES REVIEW. 2003. V. 15(1). P. 25-41. Interpretive Summary: We don¿t have enough information to forecast flows in the Rio Grande with conventional techniques. We have developed techniques for using a new satellite sensor, MODIS, to map the upper Rio Grande Basin in Colorado where snowmelt is the major contributor to streamflow. MODIS snow cover data proved to be very reliable. We input the MODIS snow cover data to the Snowmelt Runoff Model which allows us to both forecast runoff in the current year and generate future hydrographs as affected by climate change. Our forecast for 2001 was accomplished using current snow cover, a snow-covered depletion curve, and temperature and precipitation from a year similar to 2001. The forecast flow was only 14% different in volume from the measured flow with an R2=0.77. Additional studies will be necessary, but this methodology should be useful to state and federal water resources agencies.
Technical Abstract: The knowledge of snow water resources is a major concern in high elevation basins where snowmelt streamflow can make a significant contribution to the total discharge. This information is especially useful for irrigation, hydropower and water supply management. In this paper, we present a system for snow water resources evaluation, based on satellite data, that generates three products; snow cover distribution with altitude, snowmelt runoff forecasts, and simulations of the expected future snowmelt seasons using the climate change scenarios indicated by international agencies. The new generation of satellites is providing scenes of the earth with increasing quality, more spectral bands, and better spatial resolution. To take advantage of these improvements, it has been necessary to solve new problems associated with the design of the new instruments, such as the so-called ¿Bowtie Effect¿ of the MODIS (Moderate Resolution Imaging Spectroradiometer) instrument. The system developed is being currently applied to the upper Rio Grande Basin in the Colorado Rocky Mountains and to several basins in the Spanish Pyrenees. As an example, a 6-month, daily hydrograph was forecasted for the Upper Rio Grande at Del Norte, CO, for 2001 that was 14.4% different from the observed flow and had an R2=0.768. Furthermore, hydrographs were produced under conditions of changing climate progressively through the 21st century.