HR: 1330h
AN: H33B-09    [Abstracts]
TI: Integrated approach to ecohydrology of semi-arid sites in areas of complex topography and biome transitions
AU: Gutierrez, H A
EM: hugo@nmt.edu
AF: New Mexico Institute of Mining and Technology, Department of Earth and Environmental Science, Socorro, NM 87801 United States
AU: Ivanov, V Y
EM: viva@mit.edu
AF: Massachussets Institute of Technology, Department of Civil and Environmental Engineering, Cambridge, MA 02139 United States
AU: * Vivoni, E R
EM: vivoni@nmt.edu
AF: New Mexico Institute of Mining and Technology, Department of Earth and Environmental Science, Socorro, NM 87801 United States
AU: Bras, R L
EM: rlbras@mit.edu
AF: Massachussets Institute of Technology, Department of Civil and Environmental Engineering, Cambridge, MA 02139 United States
AB: Vegetation constitutes an essential link in the hydrologic cycle at the land surface - atmosphere interface. Vegetation exerts a predominant control over the partition of rainfall into soil infiltration and evapotranspiration and determines to a great extent the water budget of entire regions. Conversely, water availability has a strong influence on the vegetation dynamics, including growth rates and overall health. In semiarid areas, changes in vegetation composition can follow slight variations in climate-derived moisture availability that, in turn, have a feedback effect on the surface water and energy balance. In this study, we present an integrated approach for studying the ecohydrology of semiarid regions characterized by complex topography and transitions between different vegetation life forms (grasses, shrubs, trees). We first present a set of hypotheses on the interaction between vegetation, landscape conditions, and climate variability in biome transitions zones. These hypotheses will be tested via the combination of numerical modeling and field data collection in the Sevilleta National Wildlife Refuge, central New Mexico. The field site is a first-order drainage basin consisting of two opposing hillslopes that differentially support a shrub-grass ecosystem and a conifer-grass community. Our modeling approaches consist of an ecohydrological module coupled to a 1-D vadose zone model as well as a more complex 3-D ecohydrological framework capable of simulating full vegetation dynamics at the watershed scale. The field instrumentation and model development efforts will be used synergistically to improve our understanding of the ecohydrology of semiarid complex watersheds. We then present an analysis of the ecohydrological model simulations driven by short- term meteorological data (~10 years) as well as by longer term, synthetically-generated climate scenarios. In particular, we will focus on the response of different vegetation communities to the atmospheric forcing and the effects on the hydrologic fluxes, including changes in the water and energy balance. Finally, we point to further potential advances in the coupled simulation of the biosphere, atmosphere, and hydrosphere in semi-arid regions.
DE: 0315 Biosphere/atmosphere interactions
DE: 0400 Biogeosciences
DE: 1818 Evapotranspiration
DE: 1851 Plant ecology
DE: 1878 Water/energy interactions
SC: Hydrology [H]
MN: 2005 Joint Assembly