The objective of this paper is to provide an overview of the primary results of the Semi-Arid Land-Surface-Atmosphere (SALSA) Program in the context of improvements to our overall understanding of hydrologic, ecologic, and atmospheric processes and their interactions in a semi-arid basin. The major findings and future research needs associated with the different core components of the program are emphasized. First, remote-sensing investigations are discussed, especially those directed toward taking full advantage of the capabilities of the new generation of satellites (ERS2/ATSR2, VEGETATION, LANDSAT7, NASA-EOS). Second, we discuss parameterization of the water and energy fluxes in arid and semi-arid regions, with special emphasis on methods to aggregate these fluxes from patch scale to grid scale. Third, we address the issues related to grassland ecology and competition for water between native grass and invasive mesquite species. Fourth, findings related to the interactions between surface water, ground water, and vegetation in a semi-arid riparian system are discussed. Next, an assessment of land use and land cover change over the entire basin over a quarter century is reviewed. Finally, unsolved issues and the needs for further research are outlined. (C) 2000 Elsevier Science B.V.
Bibliographical noteFunding Information:
Financial support from the Institute of Research for Development (IRD, France), USDA-ARS Global Change Research Program, NASA grant W-18, 1997, NASA Landsat Science Team, grant No. S-41396-F, USDA National Research Initiative Grant Program, Arizona Department of Water Resources, US Environmental Protection Agency Office of Research and Development, CONACYT–Mexico (Contracts 4298P and 29340T), the French Remote-sensing Program (PNTS), the European Union through VEGETATION and ERS2/ATSR2, WATERMED projects. Support was also provided by the NASA/EOS grants (NAGW2425 and NAG5-7554), EPA, US Geological Survey, US Department of Energy (contract W-7405-ENG-36), California Institute of Technology — Jet Propulsion Laboratory (NASA, EOS/ASTER), WAU (Wageningen Agricultural University, Netherlands); CNES, CNRS, CIRAD and INRA in France. Support from the NSF-STC SAHRA (Sustainability of semi-Arid Hydrology and Riparian Areas) under Agreement No. EAR-9876800) is also gratefully acknowledged. Special thanks are extended to the ARS staff located in Tombstone, AZ for their diligent efforts and to USDA-ARS Weslaco for pilot and aircraft support. We also wish to extend our sincere thanks to the many ARS, University of Arizona, IMADES/IRD staff and students, and local volunteers who generously donated their time and expertise to make this project a success. Many thanks to Ms. Corrie Thies from the Department of Hydrology and Water Resources, University of Arizona, for editing this manuscript.
- SVAT modeling
- San Pedro river
- Vegetation functioning