|Chehbouni, A. - IRD, FRANCE|
|Watts, C. - IMADES, MEXICO|
|Kerr, Y.H. - CESBIO, FRANCE|
|Dedieu, G. - CESBIO, FRANCE|
|Kepner, W.G. - U.S. EPA, LAS VEGAS|
|Shuttleworth, W.J. - UNIV. OF ARIZ.|
|Sorooshian, S. - UNIV. OF ARIZ.|
Submitted to: Agricultural and Forest Meteorology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: January 13, 2000
Publication Date: November 20, 2000
Interpretive Summary: Arid and semi-arid regions make up almost 35 percent of the earth's land area. Rapid urbanization, groundwater mining, overgrazing, and fire suppression have permanently altered many semi-arid regions of the Southwest and northern Mexico. The serious environmental and economic consequences of these activities have led to a pressing societal need for research to provide scientific tools for decision making. In this context, an international consortium of government agencies, universities, and research laboratories designed the Semi-Arid-Land-Surface-Atmosphere (SALSA) Program. The primary goal of SALSA is to understand, model and predict the consequences of natural and human-induced change on the basin- wide water balance and ecological diversity of semiarid regions. The program focuses on the San Pedro River basin, which originates in northern Sonora, Mexico and flows north into southeastern Arizona. This paper provides an overview of the major findings of the SALSA Program research from 1995 to 1999. Major advances were made in: 1) Methods to estimate riparian vegetation water use; and, 2) Ground and remote sensing measurements to characterize, model and understand these regions.
Technical Abstract: 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 hydrological, ecological and atmospheric processes interactions in a semi-arid basin. It highlights the major findings from the different core components of the program. We first address the issue related to grassland functioning and competition for water between native (grass) and invasive vegetation species (mesquite). Second, we discuss the parameterization of the fluxes of water and energy in arid and semi-arid regions, with special emphasis on methods to aggregate these fluxes from patch scale to grid scale. Third, findings related to the interactions between surface water, groundwater, and evapotranspiration of a semi-arid riparian system are discussed. Fourth, remote sensing investigations are discussed, especially those directed toward taking full advantage of the capabilities of the new generation satellites (ERS2/ATSR2, VEGETATION, LANDSAT7, NASA-EOS). Finally, unsolved issues and the research needed in the future are outlined.